scholarly journals Laccase and Its Role in Production of Extracellular Reactive Oxygen Species during Wood Decay by the Brown Rot Basidiomycete Postia placenta

2010 ◽  
Vol 76 (7) ◽  
pp. 2091-2097 ◽  
Author(s):  
Dongsheng Wei ◽  
Carl J. Houtman ◽  
Alexander N. Kapich ◽  
Christopher G. Hunt ◽  
Daniel Cullen ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Protein Identification ◽  
Reactive Oxygen ◽  
Wood Decay ◽  
Brown Rot ◽  
Order Rate Constant ◽  
Spectrometric Analysis ◽  
Alternative Mechanism ◽  
Oxygen Species ◽  
Postia Placenta

ABSTRACT Brown rot basidiomycetes initiate wood decay by producing extracellular reactive oxygen species that depolymerize the structural polysaccharides of lignocellulose. Secreted fungal hydroquinones are considered one contributor because they have been shown to reduce Fe3+, thus generating perhydroxyl radicals and Fe2+, which subsequently react further to produce biodegradative hydroxyl radicals. However, many brown rot fungi also secrete high levels of oxalate, which chelates Fe3+ tightly, making it unreactive with hydroquinones. For hydroquinone-driven hydroxyl radical production to contribute in this environment, an alternative mechanism to oxidize hydroquinones is required. We show here that aspen wood undergoing decay by the oxalate producer Postia placenta contained both 2,5-dimethoxyhydroquinone and laccase activity. Mass spectrometric analysis of proteins extracted from the wood identified a putative laccase (Joint Genome Institute P. placenta protein identification number 111314), and heterologous expression of the corresponding gene confirmed this assignment. Ultrafiltration experiments with liquid pressed from the biodegrading wood showed that a high-molecular-weight component was required for it to oxidize 2,5-dimethoxyhydroquinone rapidly and that this component was replaceable by P. placenta laccase. The purified laccase oxidized 2,5-dimethoxyhydroquinone with a second-order rate constant near 104 M−1 s−1, and measurements of the H2O2 produced indicated that approximately one perhydroxyl radical was generated per hydroquinone supplied. Using these values and a previously developed computer model, we estimate that the quantity of reactive oxygen species produced by P. placenta laccase in wood is large enough that it likely contributes to incipient decay.

scholarly journals Gene Regulation Shifts Shed Light on Fungal Adaption in Plant Biomass Decomposers

mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Jiwei Zhang ◽  
Kevin A. T. Silverstein ◽  
Jesus David Castaño ◽  
Melania Figueroa ◽  
Jonathan S. Schilling
Keyword(s):  
Reactive Oxygen Species ◽  
Gene Regulation ◽  
Plant Biomass ◽  
Reactive Oxygen ◽  
Brown Rot ◽  
Comparative Transcriptomics ◽  
White Rot ◽  
Ecological Niches ◽  
Oxygen Species ◽  
Brown Rot Fungi

ABSTRACT Fungi dominate the recycling of carbon sequestered in woody biomass. This process of organic turnover was first evolved among “white rot” fungi that degrade lignin to access carbohydrates and later evolved multiple times toward more efficient strategies to selectively target carbohydrates—“brown rot.” The brown rot adaption was often explained by mechanisms to deploy reactive oxygen species (ROS) to oxidatively attack wood structures. However, its genetic basis remains unclear, especially in the context of gene contractions of conventional carbohydrate-active enzymes (CAZYs) relative to white rot ancestors. Here, we hypothesized that these apparent gains in brown rot efficiency despite gene losses were due, in part, to upregulation of the retained genes. We applied comparative transcriptomics to multiple species of both rot types grown across a wood wafer to create a gradient of progressive decay and to enable tracking temporal gene expression. Dozens of “decay-stage-dependent” ortho-genes were isolated, narrowing a pool of candidate genes with time-dependent regulation unique to brown rot fungi. A broad comparison of the expression timing of CAZY families indicated a temporal regulatory shift of lignocellulose-oxidizing genes toward early stages in brown rot compared to white rot, enabling the segregation of oxidative treatment ahead of hydrolysis. These key brown rot ROS-generating genes with iron ion binding functions were isolated. Moreover, transcription energy was shifted to be invested on the retained GHs in brown rot fungi to strengthen carbohydrate conversion. Collectively, these results support the hypothesis that gene regulation shifts played a pivotal role in brown rot adaptation. IMPORTANCE Fungi dominate the turnover of wood, Earth’s largest pool of aboveground terrestrial carbon. Fungi first evolved this capacity by degrading lignin to access and hydrolyze embedded carbohydrates (white rot). Multiple lineages, however, adapted faster reactive oxygen species (ROS) pretreatments to loosen lignocellulose and selectively extract sugars (brown rot). This brown rot “shortcut” often coincided with losses (>60%) of conventional lignocellulolytic genes, implying that ROS adaptations supplanted conventional pathways. We used comparative transcriptomics to further pursue brown rot adaptations, which illuminated the clear temporal expression shift of ROS genes, as well as the shift toward synthesizing more GHs in brown rot relative to white rot. These imply that gene regulatory shifts, not simply ROS innovations, were key to brown rot fungal evolution. These results not only reveal an important biological shift among these unique fungi, but they may also illuminate a trait that restricts brown rot fungi to certain ecological niches.

scholarly journals Metabolomic Dynamics Reveals Oxidative Stress in Spongy Tissue Disorder During Ripening of Mangifera indica L. Fruit

Metabolites ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 255 ◽  
Author(s):  
Pranjali Oak ◽  
Ashish Deshpande ◽  
Ashok Giri ◽  
Vidya Gupta
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Tricarboxylic Acid Cycle ◽  
Mangifera Indica ◽  
Reactive Oxygen ◽  
Spectrometric Analysis ◽  
Oxygen Species ◽  
Spongy Tissue ◽  
Mango Fruit ◽  
Alphonso Mango

Spongy tissue disorder, a mesocarp specific malady, severely affects the flavor and pulp characters of Alphonso mango fruit reducing its consumer acceptability. Here, we investigated comparative metabolomic changes that occur during ripening in healthy and spongy tissue-affected fruits using high resolution mass spectrometric analysis. During the spongy tissue formation, 46 metabolites were identified to be differentially accumulated. These putative metabolites belong to various primary and secondary metabolic pathways potentially involved in maintaining the quality of the fruit. Analysis revealed metabolic variations in tricarboxylic acid cycle and gamma amino butyric acid shunt generating reactive oxygen species, which causes stressed conditions inside the mesocarp. Further, reduced levels of antioxidants and enzymes dissipating reactive oxygen species in mesocarp deteriorate the fruit physiology. This oxidative stress all along affects the level of amino acids, sugars and enzymes responsible for flavor generation in the fruit. Our results provide metabolic insights into spongy tissue development in ripening Alphonso mango fruit.

Reactive oxygen species as agents of wood decay by fungi

2002 ◽  
Vol 30 (4) ◽  
pp. 445-453 ◽  
Author(s):  
Kenneth E. Hammel ◽  
Alexander N. Kapich ◽  
Kenneth A. Jensen ◽  
Zachary C. Ryan
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen ◽  
Wood Decay ◽  
Oxygen Species

scholarly journals A Fungal Secretome Adapted for Stress Enabled a Radical Wood Decay Mechanism

mBio ◽  
2021 ◽  
Author(s):  
Jesus Castaño ◽  
Jiwei Zhang ◽  
Mowei Zhou ◽  
Chia-Feng Tsai ◽  
Joon Yong Lee ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Walls ◽  
Critical Role ◽  
Wood Decay ◽  
Brown Rot ◽  
Oxygen Species ◽  
Decay Mechanism ◽  
Brown Rot Fungi ◽  
Carbon Recycling ◽  
Fungal Secretome

Brown rot fungi play a critical role in carbon recycling and are of industrial interest. These fungi typically use reactive oxygen species (ROS) to indiscriminately “loosen” wood cell walls at the outset of decay.

scholarly journals Oxidative Damage Control during Decay of Wood by Brown Rot Fungus Using Oxygen Radicals

2018 ◽  
Vol 84 (22) ◽  
Author(s):  
Jesus D. Castaño ◽  
Jiwei Zhang ◽  
Claire E. Anderson ◽  
Jonathan S. Schilling
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Walls ◽  
Reactive Oxygen ◽  
Brown Rot ◽  
White Rot ◽  
Ros Generation ◽  
Oxygen Species ◽  
Content Type ◽  
Brown Rot Fungi ◽  
Brown Rot Fungus

ABSTRACTBrown rot wood-degrading fungi deploy reactive oxygen species (ROS) to loosen plant cell walls and enable selective polysaccharide extraction. These ROS, including Fenton-generated hydroxyl radicals (HO˙), react with little specificity and risk damaging hyphae and secreted enzymes. Recently, it was shown that brown rot fungi reduce this risk, in part, by differentially expressing genes involved in HO˙ generation ahead of those coding carbohydrate-active enzymes (CAZYs). However, there are notable exceptions to this pattern, and we hypothesized that brown rot fungi would require additional extracellular mechanisms to limit ROS damage. To assess this, we grewPostia placentadirectionally on wood wafers to spatially segregate early from later decay stages. Extracellular HO˙ production (avoidance) and quenching (suppression) capacities among the stages were analyzed, along with the ability of secreted CAZYs to maintain activity postoxidation (tolerance). First, we found that H2O2and Fe2+concentrations in the extracellular environment were conducive to HO˙ production in early (H2O2:Fe2+ratio 2:1) but not later (ratio 1:131) stages of decay. Second, we found that ABTS radical cation quenching (antioxidant capacity) was higher in later decay stages, coincident with higher fungal phenolic concentrations. Third, by surveying enzyme activities before/after exposure to Fenton-generated HO˙, we found that CAZYs secreted early, amid HO˙, were more tolerant of oxidative stress than those expressed later and were more tolerant than homologs in the model CAZY producerTrichoderma reesei. Collectively, this indicates thatP. placentauses avoidance, suppression, and tolerance mechanisms, extracellularly, to complement intracellular differential expression, enabling this brown rot fungus to use ROS to degrade wood.IMPORTANCEWood is one of the largest pools of carbon on Earth, and its decomposition is dominated in most systems by fungi. Wood-degrading fungi specialize in extracting sugars bound within lignin, either by removing lignin first (white rot) or by using Fenton-generated reactive oxygen species (ROS) to “loosen” wood cell walls, enabling selective sugar extraction (brown rot). Although white rot lignin-degrading pathways are well characterized, there are many uncertainties in brown rot fungal mechanisms. Our study addressed a key uncertainty in how brown rot fungi deploy ROS without damaging themselves or the enzymes they secrete. In addition to revealing differentially expressed genes to promote ROS generation only in early decay, our study revealed three spatial control mechanisms to avoid/tolerate ROS: (i) constraining Fenton reactant concentrations (H2O2, Fe2+), (ii) quenching ROS via antioxidants, and (iii) secreting ROS-tolerant enzymes. These results not only offer insight into natural decomposition pathways but also generate targets for biotechnological development.

scholarly journals Proteomic Analysis of NRROS Interactome Reveals the Presence of Chaperones and Mediators of the ERAD Pathway

2018 ◽  
Author(s):  
Rajkumar Noubade ◽  
Qui Phung ◽  
Wilson Phung ◽  
Erik Verschueren ◽  
Laura Lau ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Transmembrane Protein ◽  
Protein Biosynthesis ◽  
Reactive Oxygen ◽  
Negative Regulator ◽  
Spectrometric Analysis ◽  
Functional Domain ◽  
Oxygen Species ◽  
Er Quality Control ◽  
Erad Pathway

AbstractNegative regulator of reactive oxygen species (NRROS, previously called LRRC33) is a leucine-rich repeat (LRR) domain containing, ER-resident transmembrane protein expressed primarily in lymphoid organs, especially in myeloid cells. We have previously demonstrated that NRROS regulates reactive oxygen species production by phagocytic cells by mediating degradation of NOX2 (gp91phox), a component of NOX2 complex responsible for the oxidative burst in these cells. Since LRR is the only functional domain in NRROS, it is likely to interact with other proteins for its biological functions. Here, by performing immunoprecipitation of NRROS and mass spectrometric analysis, we describe the NRROS interactome in macrophages and demonstrate that NRROS interacts with molecular chaperones/co-chaperones and mediators of the endoplasmic reticulum associated degradation (ERAD) pathway such as calnexin, suggesting a broader role for NRROS in protein biosynthesis and the ER quality control machinery.

Significant levels of extracellular reactive oxygen species produced by brown rot basidiomycetes on cellulose

FEBS Letters ◽  
2002 ◽  
Vol 531 (3) ◽  
pp. 483-488 ◽  
Author(s):  
Roni Cohen ◽  
Kenneth A Jensen ◽  
Carl J Houtman ◽  
Kenneth E Hammel
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen ◽  
Brown Rot ◽  
Oxygen Species

scholarly journals CuO enhances the photocatalytic activity of Fe₂O₃ through synergistic reactive oxygen species interactions

2021 ◽  
Author(s):  
Emily Asenath-Smith ◽  
Emma Ambrogi ◽  
Eftihia Barnes ◽  
Jonathon Brame
Keyword(s):  
Reactive Oxygen Species ◽  
Species Interactions ◽  
High Performance ◽  
Photocatalytic Performance ◽  
Low Cost ◽  
Solar Spectrum ◽  
Reactive Oxygen ◽  
Order Rate Constant ◽  
Oxygen Species ◽  
Hydrothermal Conditions

Iron oxide (α-Fe₂O₃, hematite) colloids were synthesized under hydrothermal conditions and investigated as catalysts for the photodegradation of an organic dye under broad-spectrum illumination. To enhance photocatalytic performance, Fe₂O₃ was combined with other transition-metal oxide (TMO) colloids (e.g., CuO and ZnO), which are sensitive to different regions of the solar spectrum (far visible and ultraviolet, respectively), using a ternary blending approach for compositional mixtures. For a variety of ZnO/Fe₂O₃/CuO mole ratios, the pseudo-first-order rate constant for methyl orange degradation was at least double the sum of the individual Fe₂O₃ and CuO rate constants, indicating there is an underlying synergy governing the photocatalysis reaction with these combinations of TMOs. A full compositional study was carried out to map the interactions between the three TMOs. Additional experiments probed the identity and role of reactive oxygen species and elucidated the mechanism by which CuO enhanced Fe₂O₃ photodegradation while ZnO did not. The increased photocatalytic performance of Fe2O3 in the presence of CuO was associated with hydroxyl radical ROS, consistent with heterogeneous photo-Fenton mechanisms, which are not accessible by ZnO. These results imply that low-cost photocatalytic materials can be engineered for high performance under solar illumination by selective pairing of TMOs with compatible ROS.

scholarly journals ATF4-Dependent NRF2 Transcriptional Regulation Promotes Antioxidant Protection during Endoplasmic Reticulum Stress

Cancers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 569 ◽  
Author(s):  
Carmen Sarcinelli ◽  
Helena Dragic ◽  
Marie Piecyk ◽  
Virginie Barbet ◽  
Cédric Duret ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Reactive Oxygen ◽  
Related Factor ◽  
Alternative Mechanism ◽  
Oxygen Species ◽  
Activating Transcription Factor 4 ◽  
Nrf2 Activation ◽  
Activating Transcription Factor

Endoplasmic reticulum (ER) stress generates reactive oxygen species (ROS) that induce apoptosis if left unabated. To limit oxidative insults, the ER stress PKR-like endoplasmic reticulum Kinase (PERK) has been reported to phosphorylate and activate nuclear factor erythroid 2-related factor 2 (NRF2). Here, we uncover an alternative mechanism for PERK-mediated NRF2 regulation in human cells that does not require direct phosphorylation. We show that the activation of the PERK pathway rapidly stimulates the expression of NRF2 through activating transcription factor 4 (ATF4). In addition, NRF2 activation is late and largely driven by reactive oxygen species (ROS) generated during late protein synthesis recovery, contributing to protecting against cell death. Thus, PERK-mediated NRF2 activation encompasses a PERK-ATF4-dependent control of NRF2 expression that contributes to the NRF2 protective response engaged during ER stress-induced ROS production.

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