scholarly journals Oxidoreductases and Reactive Oxygen Species in Conversion of Lignocellulosic Biomass

2018 ◽  
Vol 82 (4) ◽  
Author(s):  
Bastien Bissaro ◽  
Anikó Várnai ◽  
Åsmund K. Røhr ◽  
Vincent G. H. Eijsink
Keyword(s):  
Reactive Oxygen Species ◽  
Plant Cell Wall ◽  
Biomass Conversion ◽  
Hydrolytic Enzymes ◽  
Reactive Oxygen ◽  
Industrial Applications ◽  
Fine Tuning ◽  
Oxygen Species ◽  
Redox Systems ◽  
Polysaccharide Monooxygenases

SUMMARYBiomass constitutes an appealing alternative to fossil resources for the production of materials and energy. The abundance and attractiveness of vegetal biomass come along with challenges pertaining to the intricacy of its structure, evolved during billions of years to face and resist abiotic and biotic attacks. To achieve the daunting goal of plant cell wall decomposition, microorganisms have developed many (enzymatic) strategies, from which we seek inspiration to develop biotechnological processes. A major breakthrough in the field has been the discovery of enzymes today known as lytic polysaccharide monooxygenases (LPMOs), which, by catalyzing the oxidative cleavage of recalcitrant polysaccharides, allow canonical hydrolytic enzymes to depolymerize the biomass more efficiently. Very recently, it has been shown that LPMOs are not classical monooxygenases in that they can also use hydrogen peroxide (H2O2) as an oxidant. This discovery calls for a revision of our understanding of how lignocellulolytic enzymes are connected since H2O2is produced and used by several of them. The first part of this review is dedicated to the LPMO paradigm, describing knowns, unknowns, and uncertainties. We then present different lignocellulolytic redox systems, enzymatic or not, that depend on fluxes of reactive oxygen species (ROS). Based on an assessment of these putatively interconnected systems, we suggest that fine-tuning of H2O2levels and proximity between sites of H2O2production and consumption are important for fungal biomass conversion. In the last part of this review, we discuss how our evolving understanding of redox processes involved in biomass depolymerization may translate into industrial applications.

scholarly journals PRDX1 is essential for the viability and maintenance of reactive oxygen species in chicken DT40

2021 ◽  
Vol 43 (1) ◽  
Author(s):  
Takahito Moriwaki ◽  
Akari Yoshimura ◽  
Yuki Tamari ◽  
Hiroyuki Sasanuma ◽  
Shunichi Takeda ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Death ◽  
Intracellular Signaling ◽  
Reactive Oxygen ◽  
Fine Tuning ◽  
Oxygen Species ◽  
Ros Homeostasis ◽  
Intracellular Ros ◽  
Chromosomal Breaks ◽  
Dt40 Cells

Abstract Background Peroxiredoxin 1 (PRDX1) is a member of a ubiquitous family of thiol peroxidases that catalyze the reduction of peroxides, including hydrogen peroxide. It functions as an antioxidant enzyme, similar to catalase and glutathione peroxidase. PRDX1 was recently shown act as a sensor of reactive oxygen species (ROS) and play a role in ROS-dependent intracellular signaling pathways. To investigate its physiological functions, PRDX1 was conditionally disrupted in chicken DT40 cells in the present study. Results The depletion of PRDX1 resulted in cell death with increased levels of intracellular ROS. PRDX1-depleted cells did not show the accumulation of chromosomal breaks or sister chromatid exchange (SCE). These results suggest that cell death in PRDX1-depleted cells was not due to DNA damage. 2-Mercaptoethanol protected against cell death in PRDX1-depleted cells and also suppressed elevations in ROS. Conclusions PRDX1 is essential in chicken DT40 cells and plays an important role in maintaining intracellular ROS homeostasis (or in the fine-tuning of cellular ROS levels). Cells deficient in PRDX1 may be used as an endogenously deregulated ROS model to elucidate the physiological roles of ROS in maintaining proper cell growth.

scholarly journals Cell type-specific differences in redox regulation and proliferation after low UVA doses

2018 ◽  
Author(s):  
Sylwia Ciesielska ◽  
Patryk Bil ◽  
Karolina Gajda ◽  
Aleksandra Poterala-Hejmo ◽  
Dorota Hudy ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Redox Regulation ◽  
Cellular Proliferation ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Cell Type ◽  
Redox Systems ◽  
Human Colon Cancer ◽  
Cellular Redox ◽  
Hct116 Cells

AbstractUltraviolet A (UVA) radiation is harmful for living organisms but in low doses may stimulate cell proliferation. Our aim was to examine the relationships between exposure to different low UVA doses, cellular proliferation, and changes in cellular reactive oxygen species levels. In human colon cancer (HCT116) and melanoma (Me45) cells exposed to UVA doses comparable to environmental, the highest doses (30-50 kJ/m2) reduced clonogenic potential but some lower doses (1 and 10 kJ/m2) induced proliferation. This effect was cell type and dose specific. In both cell lines the levels of reactive oxygen species and nitric oxide fluctuated with dynamics which were influenced differently by UVA; in Me45 cells decreased proliferation accompanied the changes in the dynamics of H2O2 while in HCT116 cells those of superoxide. Genes coding for proteins engaged in redox systems were expressed differently in each cell line; transcripts for thioredoxin, peroxiredoxin and glutathione peroxidase showed higher expression in HCT116 cells whereas those for glutathione transferases and copper chaperone were more abundant in Me45 cells. We conclude that these two cell types utilize different pathways for regulating their redox status. Many mechanisms engaged in maintaining cellular redox balance have been described. Here we show that the different cellular responses to a stimulus such as a specific dose of UVA may be consequences of the use of different redox control pathways. Assays of superoxide and hydrogen peroxide level changes after exposure to UVA may clarify mechanisms of cellular redox regulation and help in understanding responses to stressing factors.

scholarly journals Roles of redox systems in apoptosis triggered by reactive oxygen species.

Ensho ◽  
2000 ◽  
Vol 20 (1) ◽  
pp. 39-44
Author(s):  
Junichi Fujii
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Redox Systems

FITNESS, a CCT domain-containing protein, deregulates reactive oxygen species levels and leads to fine-tuning trade-offs between reproductive success and defence responses in Arabidopsis

2018 ◽  
Vol 41 (10) ◽  
pp. 2328-2341 ◽  
Author(s):  
Ana Virginia Osella ◽  
Diego Alberto Mengarelli ◽  
Julieta Mateos ◽  
Shuchao Dong ◽  
Marcelo J. Yanovsky ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Reproductive Success ◽  
Reactive Oxygen ◽  
Fine Tuning ◽  
Oxygen Species ◽  
Trade Offs ◽  
Defence Responses

scholarly journals Reactive oxygen species, cellular redox systems, and apoptosis

2010 ◽  
Vol 48 (6) ◽  
pp. 749-762 ◽  
Author(s):  
Magdalena L. Circu ◽  
Tak Yee Aw
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Redox Systems ◽  
Cellular Redox

scholarly journals An Autoregulatory Loop ControllingCYP1A1 Gene Expression: Role of H2O2and NFI

1999 ◽  
Vol 19 (10) ◽  
pp. 6825-6832 ◽  
Author(s):  
Yannick Morel ◽  
Nicolas Mermod ◽  
Robert Barouki
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Reactive Oxygen Species ◽  
Gene Promoter ◽  
Reactive Oxygen ◽  
Fine Tuning ◽  
Expression Vectors ◽  
Oxygen Species ◽  
Cytochrome P450 1A1 ◽  
Down Regulation

ABSTRACT Cytochrome P450 1A1 (CYP1A1), like many monooxygenases, can produce reactive oxygen species during its catalytic cycle. Apart from the well-characterized xenobiotic-elicited induction, the regulatory mechanisms involved in the control of the steady-state activity of CYP1A1 have not been elucidated. We show here that reactive oxygen species generated from the activity of CYP1A1 limit the levels of induced CYP1A1 mRNAs. The mechanism involves the repression of theCYP1A1 gene promoter activity in a negative-feedback autoregulatory loop. Indeed, increasing the CYP1A1 activity by transfecting CYP1A1 expression vectors into hepatoma cells elicited an oxidative stress and led to the repression of a reporter gene driven by the CYP1A1 gene promoter. This negative autoregulation is abolished by ellipticine (an inhibitor of CYP1A1) and by catalase (which catalyzes H2O2 catabolism), thus implying that H2O2 is an intermediate. Down-regulation is also abolished by the mutation of the proximal nuclear factor I (NFI) site in the promoter. The transactivating domain of NFI/CTF was found to act in synergy with the arylhydrocarbon receptor pathway during the induction of CYP1A1 by 2,3,7,8-tetrachloro-p-dibenzodioxin. Using an NFI/CTF-Gal4 fusion, we show that NFI/CTF transactivating function is decreased by a high activity of CYP1A1. This regulation is also abolished by catalase or ellipticine. Consistently, the transactivating function of NFI/CTF is repressed in cells treated with H2O2, a novel finding indicating that the transactivating domain of a transcription factor can be targeted by oxidative stress. In conclusion, an autoregulatory loop leads to the fine tuning of theCYP1A1 gene expression through the down-regulation of NFI activity by CYP1A1-based H2O2 production. This mechanism allows a limitation of the potentially toxic CYP1A1 activity within the cell.

scholarly journals Reactive oxygen species and the control of vascular function

2009 ◽  
Vol 296 (3) ◽  
pp. H539-H549 ◽  
Author(s):  
Michael S. Wolin
Keyword(s):  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Vascular Function ◽  
Soluble Guanylate Cyclase ◽  
Pulmonary Arteries ◽  
Reactive Oxygen ◽  
Vascular Diseases ◽  
Oxygen Species ◽  
Redox Systems ◽  
Cellular Peroxide

This article summarizes perspectives on how reactive oxygen species (ROS) and redox signaling mechanisms participate in regulating vascular smooth muscle function that have resulted from our studies over the past 25 years in areas including oxygen sensing and the regulation of cGMP production by soluble guanylate cyclase (sGC) that were presented in the Robert M. Berne Distinguished Lectureship at the 2008 Experimental Biology Meeting. It considers mechanisms controlling the activity of sources of ROS including Nox oxidases and mitochondria by physiological stimuli, vascular diseases processes, and metabolic mechanisms linked to NAD(P)H redox and hypoxia. Metabolic interactions of individual ROS such as hydrogen peroxide with cellular peroxide metabolizing enzymes are viewed as some of the most sensitive ways of influencing cellular signaling systems. The control of cytosolic NADPH redox also seems to be a major contributor to bovine coronary arterial relaxation to hypoxia, where its oxidation functions to coordinate the lowering of intracellular calcium, whereas increased cytosolic NADPH generation in pulmonary arteries appears to maintain elevated Nox oxidase activity, and relaxation to hydrogen peroxide, which is attenuated by hypoxia. The sensitivity of sGC to nitric oxide seems to be regulated by thiol and heme redox systems controlled by cytosolic NADPH. Heme biosynthesis and metabolism are also important factors regulating the sGC system. The signaling pathways controlling oxidases and their colocalization with redox-regulated systems enables selective activation of numerous regulatory mechanisms influencing vascular function in physiological processes and the progression of aging-associated vascular diseases.

scholarly journals Fine Tuning of Reactive Oxygen Species Homeostasis Regulates Primed Immune Responses in Arabidopsis

2013 ◽  
Vol 26 (11) ◽  
pp. 1334-1344 ◽  
Author(s):  
Victoria Pastor ◽  
Estrella Luna ◽  
Jurriaan Ton ◽  
Miguel Cerezo ◽  
Pilar García-Agustín ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen ◽  
Fine Tuning ◽  
Chemical Agent ◽  
Oxygen Species ◽  
Ros Scavenging ◽  
Molecular Pattern ◽  
Glutamylcysteine Synthetase ◽  
Reduced And Oxidized Glutathione ◽  
Respiratory Burst Oxidase

Selected stimuli can prime the plant immune system for a faster and stronger defense reaction to pathogen attack. Pretreatment of Arabidopsis with the chemical agent β-aminobutyric acid (BABA) augmented H2O2 and callose production after induction with the pathogen-associated molecular pattern (PAMP) chitosan, or inoculation with the necrotrophic fungus Plectosphaerella cucumerina. However, BABA failed to prime H2O2 and callose production after challenge with the bacterial PAMP Flg22. Analysis of Arabidopsis mutants in reactive oxygen species (ROS) production (rbohD) or ROS scavenging (pad2, vtc1, and cat2) suggested a regulatory role for ROS homeostasis in priming of chitosan- and P. cucumerina-inducible callose and ROS. Moreover, rbohD and pad2 were both impaired in BABA-induced resistance against P. cucumerina. Gene expression analysis revealed direct induction of NADPH/respiratory burst oxidase protein D (RBOHD), γ-glutamylcysteine synthetase 1 (GSH1), and vitamin C defective 1 (VTC1) genes after BABA treatment. Conversely, ascorbate peroxidase 1 (APX1) transcription was repressed by BABA after challenge with chitosan or P. cucumerina, probably to provide a more oxidized environment in the cell and facilitate augmented ROS accumulation. Measuring ratios between reduced and oxidized glutathione confirmed that augmented defense expression in primed plants is associated with a more oxidized cellular status. Together, our data indicate that an altered ROS equilibrium is required for augmented defense expression in primed plants.

scholarly journals Precipitation at Room Temperature as a Fast and Versatile Method for Calcium Phosphate/TiO2 Nanocomposites Synthesis

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1523
Author(s):  
Ina Erceg ◽  
Atiđa Selmani ◽  
Andreja Gajović ◽  
Borna Radatović ◽  
Suzana Šegota ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Calcium Phosphates ◽  
Reactive Oxygen ◽  
Fine Tuning ◽  
Fast Method ◽  
Oxygen Species ◽  
Precipitation System ◽  
Significant Difference ◽  
Tio2 Nanomaterials ◽  
Metal Oxide Nanomaterials

The constantly growing need for advanced bone regeneration materials has motivated the development of calcium phosphates (CaPs) composites with a different metal or metal-oxide nanomaterials and their economical and environmentally friendly production. Here, two procedures for the synthesis of CaPs composites with TiO2 nanoplates (TiNPl) and nanowires (TiNWs) were tested, with the immersion of TiO2 nanomaterials (TiNMs) in corrected simulated body fluid (c-SBF) and precipitation of CaP in the presence of TiNMs. The materials obtained were analyzed by powder X-ray diffraction, spectroscopic and microscopic techniques, Brunauer–Emmett–Teller surface area analysis, thermogravimetric analysis, dynamic and electrophoretic light scattering, and their hemocompatibility and ability to induce reactive oxygen species were evaluated. After 28 days of immersion in c-SBF, no significant CaP coating was formed on TiNMs. However, the composites with calcium-deficient apatite (CaDHA) were obtained after one hour in the spontaneous precipitation system. In the absence of TiNMs, CaDHA was also formed, indicating that control of the CaP phase formed can be accomplished by fine-tuning conditions in the precipitation system. Although the morphology and size of crystalline domains of CaDHA obtained on the different nanomaterials differed, no significant difference was detected in their local structure. Composites showed low reactive oxygen species (ROS) production and did not induce hemolysis. The results obtained indicate that precipitation is a suitable and fast method for the preparation of CaPs/TiNMs nanocomposites which shows great potential for biomedical applications.

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