Reactive oxygen species‐responsive degradable poly(amino acid)s for biomedical use

2021 ◽  
pp. 51386
Author(s):  
Xiaoxia Fan ◽  
Sudi Zhu ◽  
Lin Yan ◽  
Hui Zhu
Keyword(s):  
Reactive Oxygen Species ◽  
Amino Acid ◽  
Reactive Oxygen ◽  
Oxygen Species

scholarly journals Arginine Biosynthesis Modulates Pyoverdine Production and Release in Pseudomonas putida as Part of the Mechanism of Adaptation to Oxidative Stress

2019 ◽  
Vol 201 (22) ◽  
Author(s):  
Laura Barrientos-Moreno ◽  
María Antonia Molina-Henares ◽  
Marta Pastor-García ◽  
María Isabel Ramos-González ◽  
Manuel Espinosa-Urgel
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Amino Acid ◽  
Pseudomonas Putida ◽  
Reactive Oxygen ◽  
Full Detail ◽  
Oxygen Species ◽  
Arginine Biosynthesis ◽  
Content Type ◽  
And Oxidative Stress

ABSTRACT Iron is essential for most life forms. Under iron-limiting conditions, many bacteria produce and release siderophores—molecules with high affinity for iron—which are then transported into the cell in their iron-bound form, allowing incorporation of the metal into a wide range of cellular processes. However, free iron can also be a source of reactive oxygen species that cause DNA, protein, and lipid damage. Not surprisingly, iron capture is finely regulated and linked to oxidative-stress responses. Here, we provide evidence indicating that in the plant-beneficial bacterium Pseudomonas putida KT2440, the amino acid l-arginine is a metabolic connector between iron capture and oxidative stress. Mutants defective in arginine biosynthesis show reduced production and release of the siderophore pyoverdine and altered expression of certain pyoverdine-related genes, resulting in higher sensitivity to iron limitation. Although the amino acid is not part of the siderophore side chain, addition of exogenous l-arginine restores pyoverdine release in the mutants, and increased pyoverdine production is observed in the presence of polyamines (agmatine and spermidine), of which arginine is a precursor. Spermidine also has a protective role against hydrogen peroxide in P. putida, whereas defects in arginine and pyoverdine synthesis result in increased production of reactive oxygen species. IMPORTANCE The results of this study show a previously unidentified connection between arginine metabolism, siderophore turnover, and oxidative stress in Pseudomonas putida. Although the precise molecular mechanisms involved have yet to be characterized in full detail, our data are consistent with a model in which arginine biosynthesis and the derived pathway leading to polyamine production function as a homeostasis mechanism that helps maintain the balance between iron uptake and oxidative-stress response systems.

scholarly journals d-amino acid oxidase promotes cellular senescence via the production of reactive oxygen species

2019 ◽  
Vol 2 (1) ◽  
pp. e201800045 ◽  
Author(s):  
Taiki Nagano ◽  
Shunsuke Yamao ◽  
Anju Terachi ◽  
Hidetora Yarimizu ◽  
Haruki Itoh ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Amino Acids ◽  
Dna Damage ◽  
Amino Acid ◽  
Cellular Senescence ◽  
Reactive Oxygen ◽  
Acid Oxidase ◽  
Dependent Manner ◽  
Oxygen Species ◽  
Amino Acid Oxidase

d-amino acid oxidase (DAO) is a flavin adenine dinucleotide (FAD)–dependent oxidase metabolizing neutral and polard-amino acids. Unlikel-amino acids, the amounts ofd-amino acids in mammalian tissues are extremely low, and therefore, little has been investigated regarding the physiological role of DAO. We have recently identifiedDAOto be up-regulated in cellular senescence, a permanent cell cycle arrest induced by various stresses, such as persistent DNA damage and oxidative stress. Because DAO produces reactive oxygen species (ROS) as byproducts of substrate oxidation and the accumulation of ROS mediates the senescence induction, we explored the relationship between DAO and senescence. We found that inhibition of DAO impaired senescence induced by DNA damage, and ectopic expression of wild-type DAO, but not enzymatically inactive mutant, enhanced it in an ROS-dependent manner. Furthermore, addition ofd-amino acids and riboflavin, a metabolic precursor of FAD, to the medium potentiated the senescence-promoting effect of DAO. These results indicate that DAO promotes senescence through the enzymatic ROS generation, and its activity is regulated by the availability of its substrate and coenzyme.

scholarly journals Candida albicans Induces Arginine Biosynthetic Genes in Response to Host-Derived Reactive Oxygen Species

2012 ◽  
Vol 12 (1) ◽  
pp. 91-100 ◽  
Author(s):  
Claudia Jiménez-López ◽  
John R. Collette ◽  
Kimberly M. Brothers ◽  
Kelly M. Shepardson ◽  
Robert A. Cramer ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Candida Albicans ◽  
Amino Acid ◽  
Reactive Oxygen ◽  
Single Amino Acid ◽  
Dependent Manner ◽  
Oxygen Species ◽  
Biosynthetic Genes ◽  
Content Type

ABSTRACTThe interaction ofCandida albicanswith phagocytes of the host's innate immune system is highly dynamic, and its outcome directly impacts the progression of infection. While the switch to hyphal growth within the macrophage is the most obvious physiological response, much of the genetic response reflects nutrient starvation: translational repression and induction of alternative carbon metabolism. Changes in amino acid metabolism are not seen, with the striking exception of arginine biosynthesis, which is upregulated in its entirety during coculture with macrophages. Using single-cell reporters, we showed here that arginine biosynthetic genes are induced specifically in phagocytosed cells. This induction is lower in magnitude than during arginine starvationin vitroand is driven not by an arginine deficiency within the phagocyte but instead by exposure to reactive oxygen species (ROS). Curiously, these genes are induced in a narrow window of sublethal ROS concentrations.C. albicanscells phagocytosed by primary macrophages deficient in thegp91phoxsubunit of the phagocyte oxidase do not express theARGpathway, indicating that the induction is dependent on the phagocyte oxidative burst.C. albicans argpathway mutants are retarded in germ tube and hypha formation within macrophages but are not notably more sensitive to ROS. We also find that theARGpathway is regulated not by the general amino acid control response but by transcriptional regulators similar to theSaccharomyces cerevisiaeArgR complex. In summary, phagocytosis induces this single amino acid biosynthetic pathway in an ROS-dependent manner.

scholarly journals Amino Acid Deprivation Decreases Intracellular Levels of Reactive Oxygen Species in Hepatic Stellate Cells

2010 ◽  
Vol 26 (3) ◽  
pp. 281-290 ◽  
Author(s):  
Elena Arriazu ◽  
María P. Pérez de Obanos ◽  
María J. López-Zabalza ◽  
María T. Herraiz ◽  
María J. Iraburu
Keyword(s):  
Reactive Oxygen Species ◽  
Amino Acid ◽  
Hepatic Stellate Cells ◽  
Reactive Oxygen ◽  
Stellate Cells ◽  
Oxygen Species ◽  
Amino Acid Deprivation

scholarly journals Amino acid oxidation of the D1 and D2 proteins by oxygen radicals during photoinhibition of Photosystem II

2017 ◽  
Vol 114 (11) ◽  
pp. 2988-2993 ◽  
Author(s):  
Ravindra Kale ◽  
Annette E. Hebert ◽  
Laurie K. Frankel ◽  
Larry Sallans ◽  
Terry M. Bricker ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Amino Acid ◽  
Photosystem Ii ◽  
Light Stress ◽  
Reactive Oxygen ◽  
Nonheme Iron ◽  
Oxidative Modification ◽  
Oxygen Species ◽  
Oxidatively Modified ◽  
D1 And D2 Proteins

The Photosystem II reaction center is vulnerable to photoinhibition. The D1 and D2 proteins, lying at the core of the photosystem, are susceptible to oxidative modification by reactive oxygen species that are formed by the photosystem during illumination. Using spin probes and EPR spectroscopy, we have determined that both O2•− and HO• are involved in the photoinhibitory process. Using tandem mass spectroscopy, we have identified a number of oxidatively modified D1 and D2 residues. Our analysis indicates that these oxidative modifications are associated with formation of HO• at both the Mn4O5Ca cluster and the nonheme iron. Additionally, O2•− appears to be formed by the reduction of O2 at either PheoD1 or QA. Early oxidation of D1:332H, which is coordinated with the Mn1 of the Mn4O5Ca cluster, appears to initiate a cascade of oxidative events that lead to the oxidative modification of numerous residues in the C termini of the D1 and D2 proteins on the donor side of the photosystem. Oxidation of D2:244Y, which is a bicarbonate ligand for the nonheme iron, induces the propagation of oxidative reactions in residues of the D-de loop of the D2 protein on the electron acceptor side of the photosystem. Finally, D1:130E and D2:246M are oxidatively modified by O2•− formed by the reduction of O2 either by PheoD1•− or QA•−. The identification of specific amino acid residues oxidized by reactive oxygen species provides insights into the mechanism of damage to the D1 and D2 proteins under light stress.

scholarly journals Gamma-aminobutyric acid (GABA) alleviates salt damage in tomato by modulating Na+ uptake, the GAD gene, amino acid synthesis and reactive oxygen species metabolism

2020 ◽  
Author(s):  
Xiaolei Wu ◽  
Qiuying Jia ◽  
Shengxin Ji ◽  
Binbin Gong ◽  
Jingrui Li ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Salt Stress ◽  
Amino Acid ◽  
Reactive Oxygen ◽  
Active Oxygen ◽  
Oxygen Species ◽  
Tomato Plants ◽  
Salt Damage ◽  
Amino Acid Contents ◽  
Gad Activity

Abstract Background Gamma-amino butyric acid (GABA), a four-carbon nonprotein ogenic amino acid, is involved in plant abiotic stress resistance. Previous studies have reported that GABA acts as a signal substance or metabolic product by regulating cytoplasmic pH, polyamine biosynthesis and degradation, NO3− reduction and assimilation, and antioxidant responses in a variety of crops under various environmental stresses. The main purpose of our study was to explore the regulatory mechanism by which exogenous GABA enhances salt tolerance in tomato (Solanum lycopersicum L.) and its effects on the functions of key enzymes. Results Exogenous application of 5 mM GABA significantly reduced the salt damage index and increased the plant height, chlorophyll content and dry and fresh weights of tomato plants treated with 175 mM NaCl. GABA significantly reduced Na+ accumulation in leaves and roots by preventing Na+ influx in roots and transportation to leaves. Cloning of the sequences of four SlGAD genes revealed that SlGAD genes played an important role in enhancing the resistance of tomato plants to NaCl stress with GABA application. Among the SlGAD genes, SlGAD1 was the most sensitive and contributed the most to the increase in GAD activity under salt stress even if the SlGAD2 transcriptional expression was the prominent under normal conditions. GABA increased the GAD activity and amino acid contents in tomato leaves compared with the levels under salt stress alone, especially the levels of GABA and proline. In addition, GABA treatment significantly alleviated the active oxygen-related injury of seedlings under salt stress by increasing the activities of antioxidant enzymes and decreasing the contents of active oxygen species (O2∙ and H2O2) and malondialdehyde (MDA). Conclusion Our data revealed a positive effect of GABA on the resistance of tomato seedlings to salt stress, which was closely associated with GABA's effects on Na+ flux and transportation, the expression and activity of SlGADs, amino acid contents and the metabolism of reactive oxygen species. Exogenous GABA influences NaCl-treated tomato plants by reducing Na+ influx into root and inducing osmotic regulation and antioxidant reactions by increasing SlGAD1 expression and GAD activity, the contents of endogenous GABA and proline and antioxidant enzyme activity.

Why is d-serine nephrotoxic and α-aminoisobutyric acid protective?

2007 ◽  
Vol 293 (1) ◽  
pp. F382-F390 ◽  
Author(s):  
Alexander W. Krug ◽  
Katharina Völker ◽  
William H. Dantzler ◽  
Stefan Silbernagl
Keyword(s):  
Reactive Oxygen Species ◽  
Amino Acid ◽  
Reactive Oxygen ◽  
Proximal Tubules ◽  
Tubular Damage ◽  
Acid Oxidase ◽  
Oxygen Species ◽  
Amino Acid Oxidase ◽  
Aminoisobutyric Acid ◽  
Serine Metabolism

d-Serine selectively causes necrosis of S3 segments of proximal tubules in rats. This leads to aminoaciduria and glucosuria. Coinjection of the nonmetabolizable amino acid α-aminoisobutyric acid (AIB) prevents the tubulopathy. d-serine is selectively reabsorbed in S3, thereby gaining access to peroxisomal d-amino acid oxidase (d-AAO). d-AAO-mediated metabolism produces reactive oxygen species. We determined the fractional excretion of amino acids and glucose in rats after intraperitoneal injection of d-serine alone or together with reduced glutathione (GSH) or AIB. Both compounds prevented the hyperaminoaciduria. We measured GSH concentrations in renal tissue before (control) and after d-serine injection and found that GSH levels decreased to ∼30% of control. This decrease was prevented when equimolar GSH was coinjected with d-serine. To find out why AIB protected the tubule from d-serine toxicity, we microinfused d-[14C]serine or [14C]AIB (0.36 mmol/l) together with [3H]inulin in late proximal tubules in vivo and measured the radioactivity in the final urine. Fractional reabsorption of d-[14C]serine and [14C]AIB amounted to 55 and 70%, respectively, and 80 mmol/l of AIB or d-serine mutually prevented reabsorption to a great extent. d-AAO activity measured in vitro (using d-serine as substrate) was not influenced by a 10-fold higher AIB concentration. We conclude from these results that 1) d-AAO-mediated d-serine metabolism lowers renal GSH concentrations and thereby provokes tubular damage because reduction of reactive oxygen species by GSH is diminished and 2) AIB prevents d-serine-induced tubulopathy by inhibition of d-serine uptake in S3 segments rather than by interfering with intracellular d-AAO-mediated d-serine metabolism.

scholarly journals Hsp90 Is Cleaved by Reactive Oxygen Species at a Highly Conserved N-Terminal Amino Acid Motif

PLoS ONE ◽  
2012 ◽  
Vol 7 (7) ◽  
pp. e40795 ◽  
Author(s):  
Raphaël Beck ◽  
Nicolas Dejeans ◽  
Christophe Glorieux ◽  
Mélanie Creton ◽  
Edouard Delaive ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Amino Acid ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Amino Acid Motif ◽  
Terminal Amino Acid ◽  
Terminal Amino
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