scholarly journals Mechanisms of Manganese(II) Oxidation by Filamentous Ascomycete Fungi Vary With Species and Time as a Function of Secretome Composition

2021 ◽  
Vol 12 ◽  
Author(s):  
Carolyn A. Zeiner ◽  
Samuel O. Purvine ◽  
Erika Zink ◽  
Si Wu ◽  
Ljiljana Paša-Tolić ◽  
...  
Keyword(s):  
Physiological Role ◽  
Oxidative Capacity ◽  
White Rot ◽  
Lignocellulose Degradation ◽  
Filamentous Ascomycete ◽  
Solid Substrates ◽  
Gmc Oxidoreductase ◽  
Ascomycete Fungi ◽  
Species Specific ◽  
Glyoxal Oxidase

Manganese (Mn) oxides are among the strongest oxidants and sorbents in the environment, and Mn(II) oxidation to Mn(III/IV) (hydr)oxides includes both abiotic and microbially-mediated processes. While white-rot Basidiomycete fungi oxidize Mn(II) using laccases and manganese peroxidases in association with lignocellulose degradation, the mechanisms by which filamentous Ascomycete fungi oxidize Mn(II) and a physiological role for Mn(II) oxidation in these organisms remain poorly understood. Here we use a combination of chemical and in-gel assays and bulk mass spectrometry to demonstrate secretome-based Mn(II) oxidation in three phylogenetically diverse Ascomycetes that is mechanistically distinct from hyphal-associated Mn(II) oxidation on solid substrates. We show that Mn(II) oxidative capacity of these fungi is dictated by species-specific secreted enzymes and varies with secretome age, and we reveal the presence of both Cu-based and FAD-based Mn(II) oxidation mechanisms in all 3 species, demonstrating mechanistic redundancy. Specifically, we identify candidate Mn(II)-oxidizing enzymes as tyrosinase and glyoxal oxidase in Stagonospora sp. SRC1lsM3a, bilirubin oxidase in Stagonospora sp. and Paraconiothyrium sporulosum AP3s5-JAC2a, and GMC oxidoreductase in all 3 species, including Pyrenochaeta sp. DS3sAY3a. The diversity of the candidate Mn(II)-oxidizing enzymes identified in this study suggests that the ability of fungal secretomes to oxidize Mn(II) may be more widespread than previously thought.

scholarly journals Doing it alone: Unisexual reproduction in filamentous ascomycete fungi

2021 ◽  
Vol 35 ◽  
pp. 1-13
Author(s):  
Andi M. Wilson ◽  
Raphael Gabriel ◽  
Steven W. Singer ◽  
Timo Schuerg ◽  
P. Markus Wilken ◽  
...  
Keyword(s):  
Filamentous Ascomycete ◽  
Unisexual Reproduction ◽  
Ascomycete Fungi

scholarly journals Identification of an Oligosaccharide Dehydrogenase from Pycnoporus Cinnabarinus Provides Insights into Fungal Breakdown of Lignocellulose

2021 ◽  
Author(s):  
Gabriele Cerutti ◽  
Elena Gugole ◽  
Linda Celeste Montemiglio ◽  
Annick Turbé-Doan ◽  
Dehbia Chena ◽  
...  
Keyword(s):  
Function Analysis ◽  
Sequence Similarity ◽  
Functional Characterization ◽  
Physiological Role ◽  
Free Form ◽  
Lignocellulose Degradation ◽  
Carbohydrate Active Enzymes ◽  
Recognition Mechanism ◽  
Pycnoporus Cinnabarinus ◽  
Enzymatic Function

Abstract Background: Fungal glucose dehydrogenases (GDHs) are FAD-dependent enzymes belonging to the glucose-methanol-choline oxidoreductase superfamily. These enzymes are classified in the “Auxiliary Activity” family 3 (AA3) of the Carbohydrate-Active enZymes database, and more specifically in subfamily AA3_2, that also includes the closely related flavoenzymes aryl-alcohol oxidase and glucose 1-oxidase. Based on sequence similarity to known fungal GDHs, an AA3_2 enzyme active on glucose was identified in the genome of Pycnoporus cinnabarinus, a model Basidiomycete able to completely degrade lignin.Results: In our work, substrate screening and functional characterization showed an unexpected preferential activity of this enzyme toward oligosaccharides containing a b(1à3) glycosidic bond, with the highest efficiency observed for the disaccharide laminaribiose. Despite its sequence similarity to GDHs, we defined a novel enzymatic activity, namely oligosaccharide dehydrogenase (ODH), for this enzyme. The crystallographic structures of ODH in the sugar-free form and in complex with glucose and laminaribiose unveiled a peculiar saccharide recognition mechanism which is not shared with previously characterized AA3 oxidoreductases and accounts for ODH preferential activity toward oligosaccharides. The sugar molecules in the active site of ODH are mainly stabilized through CH-p interactions with aromatic residues rather than through hydrogen bonds with highly conserved residues, as observed instead for the fungal glucose dehydrogenases and oxidases characterized to date. Finally, three sugar-binding sites were identified on ODH external surface, which were not previously observed and might be of importance in the physiological scenario.Conclusions: Structure-function analysis of ODH is consistent with its role as an auxiliary enzyme in lignocellulose degradation and unveils yet another enzymatic function within the AA3 family of the Carbohydrate-Active enZymes database. Our findings allow deciphering the molecular determinants of substrate binding and provide insight into the physiological role of ODH, opening new perspectives to exploit biodiversity for lignocellulose transformation into fuels and chemicals.

scholarly journals Unique Patterns of Mating Pheromone Presence and Absence could Result in the Ambiguous Sexual Behaviours of Colletotrichum Species

2020 ◽  
Author(s):  
Andrea Melissa Wilson ◽  
RV Lelwala ◽  
PWJ Taylor ◽  
MJ Wingfield ◽  
BD WINGFIELD
Keyword(s):  
Mating Type ◽  
Molecular Mechanisms ◽  
Mating Strategies ◽  
Mating Partner ◽  
Filamentous Ascomycete ◽  
Sexual Behaviours ◽  
History Of ◽  
Ascomycete Fungi ◽  
Presence And Absence ◽  
Sexual Progeny

Abstract Background: Colletotrichum species are known to engage in unique sexual behaviours that differ significantly from the mating strategies of other filamentous ascomycete species. Most ascomycete fungi require the expression of both the MAT1-1-1 and MAT1-2-1 genes to regulate mating type and induce sexual reproduction. In contrast, all isolates of Colletotrichum are known to harbour only the MAT1-2-1 gene and yet, are capable of recognizing suitable mating partners and producing sexual progeny. The molecular mechanisms contributing to mating types and behaviours in Colletotrichum are thus unknown. Results: A comparative genomics approach analysing genomes from 47 Colletotrichum isolates was used to elucidate a putative molecular mechanism underlying the unique sexual behaviours observed in Colletotrichum species. The existence of only the MAT1-2 idiomorph was confirmed across all species included in this study. Comparisons at the loci harbouring the two mating pheromones and their cognate receptors revealed interesting patterns of gene presence and absence as well as gene loss. The results also showed that these genes have been lost multiple times over the evolutionary history of this genus. Conclusion: The multiple losses of the pheromone genes in these species suggest strong selection against the typical mating strategies seen in other species. This further suggests that these pheromones no longer play a role in mating type determination and that the species of this genus have undiscovered mechanisms by which to control mating type and mating partner recognition. This research thus provides a base from which further interrogation of this topic can take place.

scholarly journals Protein modification with ISG15 blocks coxsackievirus pathology by antiviral and metabolic reprogramming

2020 ◽  
Vol 6 (11) ◽  
pp. eaay1109 ◽  
Author(s):  
Meike Kespohl ◽  
Clara Bredow ◽  
Karin Klingel ◽  
Martin Voß ◽  
Anna Paeschke ◽  
...  
Keyword(s):  
Protein Modification ◽  
Shotgun Proteomics ◽  
Oxidative Capacity ◽  
Metabolic Reprogramming ◽  
Major Type ◽  
Infection Model ◽  
Type I ◽  
Synergistic Activity ◽  
Cardiac Damage ◽  
Species Specific

Protein modification with ISG15 (ISGylation) represents a major type I IFN–induced antimicrobial system. Common mechanisms of action and species-specific aspects of ISGylation, however, are still ill defined and controversial. We used a multiphasic coxsackievirus B3 (CV) infection model with a first wave resulting in hepatic injury of the liver, followed by a second wave culminating in cardiac damage. This study shows that ISGylation sets nonhematopoietic cells into a resistant state, being indispensable for CV control, which is accomplished by synergistic activity of ISG15 on antiviral IFIT1/3 proteins. Concurrent with altered energy demands, ISG15 also adapts liver metabolism during infection. Shotgun proteomics, in combination with metabolic network modeling, revealed that ISG15 increases the oxidative capacity and promotes gluconeogenesis in liver cells. Cells lacking the activity of the ISG15-specific protease USP18 exhibit increased resistance to clinically relevant CV strains, therefore suggesting that stabilizing ISGylation by inhibiting USP18 could be exploited for CV-associated human pathologies.

Oxalate production by fungi: its role in pathogenicity and ecology in the soil environment

1996 ◽  
Vol 42 (9) ◽  
pp. 881-895 ◽  
Author(s):  
Martin V. Dutton ◽  
Christine S. Evans
Keyword(s):  
Oxalic Acid ◽  
Calcium Oxalate ◽  
Cell Walls ◽  
Divalent Cations ◽  
White Rot ◽  
Lignocellulose Degradation ◽  
Calcium Oxalate Crystals ◽  
Copper Salts ◽  
Oxalate Crystals ◽  
Oxalate Secretion

Oxalate secretion by fungi provides many advantages for their growth and colonization of substrates. The role of oxalic acid in pathogenesis is through acidification of host tissues and sequestration of calcium from host cell walls. The formation of calcium oxalate crystals weakens the cell walls, thereby allowing polygalacturonase to effect degradation more rapidly in a synergistic response. There is good correlation between pathogenesis, virulence, and oxalic acid secretion. Solubility of soil nutrients is achieved by soil-living species, when cations freed by oxalate diffusing in clay layers increases the effective solubility of Al and Fe. Oxalate retained in hyphal mats of mycorrhizal species increases phosphate and sulphate availability. The formation of calcium oxalate crystals provides a reservoir of calcium in the ecosystem. The ability of oxalate to bind divalent cations permits detoxification of copper, particularly evident in wood preserved with copper salts. Oxalate plays a unique role in lignocellulose degradation by wood-rotting basidiomycetes, acting as a low molecular mass agent initiating decay. In addition, in white-rot fungi oxalate acts as a potential electron donor for lignin-peroxidase catalysed reduction and chelates manganese, allowing the dissolution of Mn3+from the manganese–enzyme complex and thus stimulating extracellular manganese peroxidase activity. The biosynthesis and degradation of oxalate are discussed.Key words: oxalic acid, calcium oxalate, pathogenicity, fungi.

Lignin degrading system of white-rot fungi and its exploitation for dye decolorization

2002 ◽  
Vol 48 (10) ◽  
pp. 857-870 ◽  
Author(s):  
Vishal Shah ◽  
Frantisek Nerud
Keyword(s):  
Lignin Degradation ◽  
White Rot Fungi ◽  
Alcohol Oxidase ◽  
Dye Decolorization ◽  
White Rot ◽  
Low Molecular Weight ◽  
Low Molecular Weight Compounds ◽  
Pyranose Oxidase ◽  
Degrading System ◽  
Glyoxal Oxidase

With global attention and research now focused on looking for the abatement of pollution, white-rot fungi is one of the hopes of the future. The lignin-degrading ability of these fungi have been the focus of attention for many years and have been exploited for a wide array of human benefits. This review highlights the various enzymes produced by white-rot fungi for lignin degradation, namely laccases, peroxidases, aryl alcohol oxidase, glyoxal oxidase, and pyranose oxidase. Also discussed are the various radicals and low molecular weight compounds that are being produced by white-rot fungi and its role in lignin degradation. A brief summary on the developments in research of decolorization of dyes using white-rot fungi has been made.Key words: lignin degradation, white-rot fungi, laccase, peroxidase, radicals, dye decolorization.

scholarly journals Functional role of respiratory supercomplexes in mice: segmentation of the Qpool and SCAF1

2019 ◽  
Author(s):  
Enrique Calvo ◽  
Sara Cogliati ◽  
Pablo Hernansanz-Agustín ◽  
Marta Loureiro-López ◽  
Adela Guarás ◽  
...  
Keyword(s):  
Quantitative Data ◽  
Functional Role ◽  
Physiological Role ◽  
Oxidative Capacity ◽  
Wild Type ◽  
Knock Out ◽  
Transport Chain ◽  
Native Gel ◽  
Blue Native

SummaryMitochondrial respiratory complexes assemble into different forms of supercomplexes (SC). In particular, SC III2+IV require the SCAF1 protein. However, the structural role of this factor in the formation of the respirasome (I+III2+IV) and the physiological role of SCs are controversial. Here, we study C57BL/6J mice harbouring either non-functional SCAF1, the full knock-out for SCAF1 or the wild-type version of the protein and found a growth and exercise phenotype due to the lack of functional SCAF1. By combining quantitative data-independent proteomics, high resolution 2D Blue Native Gel Electrophoresis and functional analysis of enriched respirasome fractions, we show that SCAF1 confers structural attachment between III2 and IV within the respirasome, increases NADH-dependent respiration and reduces ROS production. Furthermore, through the expression of AOX in cells and mice we confirm that CI-CIII superassembly segments the CoQ in two pools and modulates CI-NADH oxidative capacity. These data demonstrate that SC assembly, regulated by SCAF1, modulates the functionality of the electron transport chain.

scholarly journals Immune-Enhancing Effect of Submerged Culture of Ceriporia lacerata Mycelia on Cyclophosphamide-Induced Immunosuppressed Mice and the Underlying Mechanisms in Macrophages

2022 ◽  
Vol 23 (2) ◽  
pp. 597
Author(s):  
Yong Pil Hwang ◽  
Gi Ho Lee ◽  
Thi Hoa Pham ◽  
Mi Yeon Kim ◽  
Chae Yeon Kim ◽  
...  
Keyword(s):  
White Rot ◽  
Extracellular Polysaccharides ◽  
Lignocellulose Degradation ◽  
Immune Functions ◽  
Submerged Cultures ◽  
Raw264.7 Macrophages ◽  
Tnf Α ◽  
Ifn Γ ◽  
Underlying Mechanisms ◽  
Immunosuppressed Mice

The white-rot fungi Ceriporia lacerata is used in bioremediation, such as lignocellulose degradation, in nature. Submerged cultures and extracts of C. lacerata mycelia (CLM) have been reported to contain various active ingredients, including β-glucan and extracellular polysaccharides, and to exert anti-diabetogenic properties in mice and cell lines. However, the immunostimulatory effects have not yet been reported. This study aimed to identify the immunomodulatory effects, and underlying mechanisms thereof, of submerged cultures of CLM using RAW264.7 macrophages and cyclophosphamide (CTX)-induced immunosuppression in mice. Compared to CTX-induced immunosuppressed mice, the spleen and thymus indexes in mice orally administered CLM were significantly increased; body weight loss was alleviated; and natural killer (NK) cytotoxicity, lymphocyte proliferation, and cytokine (tumor necrosis factor [TNF]-α, interferon [IFN]-γ, and interleukin [IL]-2) production were elevated in the serum. In RAW264.7 macrophages, treatment with CLM induced phagocytic activity, increased the production of nitric oxide (NO), and promoted mRNA expression of the immunomodulatory cytokines TNF-α, IFN-γ, IL-1β, IL-6, IL-10, and IL-12. In addition, CLM increased the inducible NO synthase (iNOS) concentration in macrophages, similar to lipopolysaccharide (LPS) stimulation. Mechanistic studies showed that CLM induced the activation of the NF-κB, PI3k/Akt, ERK1/2, and JNK1/2 pathways. Moreover, the phosphorylation of NF-κB and IκB induced by CLM in RAW264.7 cells was suppressed by specific MAPKs and PI3K inhibitors. Further experiments with a TLR4 inhibitor demonstrated that the production of TNF-α, IL-1β, and IL-6 induced by CLM was decreased after TLR4 was blocked. Overall, CLM protected against CTX-induced adverse reactions by enhancing humoral and cellular immune functions, and has potential as an immunomodulatory agent.

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