scholarly journals Introduction of the Aspergillus fumigatus α-1,2-mannosidase MsdS into Trichoderma reesei leads to abnormal polarity and improves the ligno-cellulose degradation

2020 ◽  
Author(s):  
Prakriti Sharma Ghimire ◽  
Haomiao Ouyang ◽  
Guangya Zhao ◽  
Mingming Xie ◽  
Hui Zhou ◽  
...  
Keyword(s):  
Cell Wall ◽  
Aspergillus Fumigatus ◽  
Trichoderma Reesei ◽  
Protein Secretion ◽  
Cellulose Degradation ◽  
Fungal Cell ◽  
Wall Defect ◽  
New Strategy ◽  
Species Specific ◽  
First Time

ABSTRACTα-1,2-Mannosidase is an important enzyme essential for N-glycan processing and plays a significant role in the biosynthesis and organization of fungal cell wall. Lacking of α-1,2-mannosidase leads to cell wall defect in yeast and filamentous fungi. Trichoderma reesei is known to be non-toxic to human, and its N-glycan on secreted glycoprotein is Man8GlcNAc2. To evaluate the significance of the N-glycan processing in T. reesei, in this study Aspergillus fumigatus α-1, 2-mannosidase MsdS, an enzyme that cleaves N-linked Man8GlcNAc2 in Golgi to produce Man6GlcNAc2 on secreted glycoprotein, was introduced into T. reesei. The msdS-expressing strain Tr-MsdS produced a major glycoform of Man6GlcNAc2 on its secreted glycoproteins, instead of Man8GlcNAc2 in the parent strain. Although the cell wall content of msdS-expressing strain Tr-MsdS was changed, it appeared that the cell wall integrity was not affected. However, phenotypes such as increased conidiation, multiple budding and random branching were observed in strain Tr-MsdS. In addition, expression of MsdS into T. ressei also affected protein secretion and improved the ligno-cellulose degradation of T. reesei. Our results indicate that processing of the N-glycan is species-specific and plays an important role in protein secretion in T. reesei, specially cellulases. Also, our results provide a new strategy to improve cellulases production by interfering the N-glycan processing in T. reesei.ImportanceFor the first time, the N-glycan processing is shown to play an important role in polarized growth and protein secretion in T. reesei. In addition, our results show that alterated N-glycan processing enhances cellulose degradation, which provides a strategy to improve cellulases production in T. reesei.

scholarly journals Introduction of the Aspergillus fumigatus α-1,2-mannosidase MsdS into Trichoderma reesei improves the ligno-cellulose degradation

2020 ◽  
Author(s):  
Prakriti Sharma Ghimire ◽  
Haomiao Ouyang ◽  
Guangya Zhao ◽  
Mingming Xie ◽  
Hui Zhou ◽  
...  
Keyword(s):  
Cell Wall ◽  
Aspergillus Fumigatus ◽  
Trichoderma Reesei ◽  
Protein Secretion ◽  
Cellulose Degradation ◽  
Fungal Cell ◽  
Wall Defect ◽  
New Strategy ◽  
Species Specific ◽  
Important Enzyme

Abstract Background: a-1,2-Mannosidase is an important enzyme essential for N-glycan processing and plays a significant role in the biosynthesis and organization of fungal cell wall. Lacking of α-1,2-mannosidase leads to cell wall defect in yeast and filamentous fungi. In Trichoderma reesei, a fungus known to be non-toxic to human, its N-glycan on secreted glycoprotein is Man8GlcNAc2, which is different from that in Aspergillus fumigatus. To evaluate the significance of the N-glycan processing in T. reesei, in this study A. fumigatus α-1, 2-mannosidase MsdS, an enzyme that cleaves N-linked Man8GlcNAc2 in Golgi to produce Man6GlcNAc2 on secreted glycoprotein, was introduced into T. reesei.Results: The msdS-expressing strain Tr-MsdS produced a major glycoform of Man6GlcNAc2 on its secreted glycoproteins, instead of Man8GlcNAc2 in the parent strain. Although the cell wall content of msdS-expressing strain Tr-MsdS was changed, it appeared that the cell wall integrity was not affected. However, phenotypes such as increased conidiation, multiple budding and random branching were observed in strain Tr-MsdS. In addition, expression of MsdS into T. ressei also affected protein secretion and improved the ligno-cellulose degradation of T. reesei.Conclusions: Our results indicate that processing of the N-glycan is species-specific and plays an important role in protein secretion in T. reesei, specially cellulases. Also, our results provide a new strategy to improve cellulases production by interfering the N-glycan processing in T. reesei.

scholarly journals Monoclonal Immunoglobulin G1 Directed against Aspergillus fumigatus Cell Wall Glycoprotein Protects against Experimental Murine Aspergillosis

2005 ◽  
Vol 12 (9) ◽  
pp. 1063-1068 ◽  
Author(s):  
Ashok K. Chaturvedi ◽  
A. Kavishwar ◽  
G. B. Shiva Keshava ◽  
P. K. Shukla
Keyword(s):  
Cell Wall ◽  
Aspergillus Fumigatus ◽  
Protective Efficacy ◽  
Wide Spectrum ◽  
Kidney Tissue ◽  
Survival Times ◽  
Fungal Cell ◽  
New Strategy

ABSTRACT Most of the biological functions related to pathogenicity and virulence reside in the fungal cell wall, which, being the outermost part of the cell, mediates the host-fungus interplay. For these reasons much effort has focused on the discovery of useful inhibitors of cell wall glucan, chitin, and mannoprotein biosynthesis. In the absence of a wide-spectrum, safe, and potent antifungal agent, a new strategy for antifungal therapy is directed towards the development of monoclonal antibodies (MAbs). In the present study the MAb A9 (immunoglobulin G1 [IgG1]) was identified from hybridomas raised in BALB/c mice immunized with cell wall antigen of Aspergillus fumigatus. The immunoreactive epitopes for this IgG1 MAb appeared to be associated with a peptide moiety, and indirect immunofluorescence microscopy revealed its binding to the cell wall surface of hyphae as well as with swollen conidia. MAb A9 inhibited hyphal development as observed by MTT [3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay (25.76%), reduced the duration of spore germination, and exerted an in vitro cidal effect against Aspergillus fumigatus. The in vivo protective efficacy of MAb A9 was also evaluated in a murine model of invasive aspergillosis, where a reduction in CFU (>4 log10 units) was observed in kidney tissue of BALB/c mice challenged with A. fumigatus (2 × 105 CFU/ml) and where enhanced mean survival times (19.5 days) compared to the control (7.1 days) and an irrelevant MAb (6.1 days) were also observed.

Protein O-mannosylation affects protein secretion, cell wall integrity and morphogenesis in Trichoderma reesei

2020 ◽  
Vol 144 ◽  
pp. 103440 ◽  
Author(s):  
Guangya Zhao ◽  
Yueqiang Xu ◽  
Haomiao Ouyang ◽  
Yuanming Luo ◽  
Shutao Sun ◽  
...  
Keyword(s):  
Cell Wall ◽  
Trichoderma Reesei ◽  
Protein Secretion ◽  
Cell Wall Integrity

scholarly journals The Transcription Factor SomA Synchronously Regulates Biofilm Formation and Cell Wall Homeostasis in Aspergillus fumigatus

mBio ◽  
2020 ◽  
Vol 11 (6) ◽  
Author(s):  
Yuan Chen ◽  
Francois Le Mauff ◽  
Yan Wang ◽  
Ruiyang Lu ◽  
Donald C. Sheppard ◽  
...  
Keyword(s):  
Cell Wall ◽  
Transcription Factor ◽  
Aspergillus Fumigatus ◽  
Biofilm Formation ◽  
Wall Stress ◽  
Fungal Cell ◽  
Glucan Synthase ◽  
Content Type ◽  
Cell Wall Stress ◽  
Chitin Synthases

ABSTRACT Polysaccharides are key components of both the fungal cell wall and biofilm matrix. Despite having distinct assembly and regulation pathways, matrix exopolysaccharide and cell wall polysaccharides share common substrates and intermediates in their biosynthetic pathways. It is not clear, however, if the biosynthetic pathways governing the production of these polysaccharides are cooperatively regulated. Here, we demonstrate that cell wall stress promotes production of the exopolysaccharide galactosaminogalactan (GAG)-depend biofilm formation in the major fungal pathogen of humans Aspergillus fumigatus and that the transcription factor SomA plays a crucial role in mediating this process. A core set of SomA target genes were identified by transcriptome sequencing and chromatin immunoprecipitation coupled to sequencing (ChIP-Seq). We identified a novel SomA-binding site in the promoter regions of GAG biosynthetic genes agd3 and ega3, as well as its regulators medA and stuA. Strikingly, this SomA-binding site was also found in the upstream regions of genes encoding the cell wall stress sensors, chitin synthases, and β-1,3-glucan synthase. Thus, SomA plays a direct regulation of both GAG and cell wall polysaccharide biosynthesis. Consistent with these findings, SomA is required for the maintenance of normal cell wall architecture and compositions in addition to its function in biofilm development. Moreover, SomA was found to globally regulate glucose uptake and utilization, as well as amino sugar and nucleotide sugar metabolism, which provides precursors for polysaccharide synthesis. Collectively, our work provides insight into fungal adaptive mechanisms in response to cell wall stress where biofilm formation and cell wall homeostasis were synchronously regulated. IMPORTANCE The cell wall is essential for fungal viability and is absent from human hosts; thus, drugs disrupting cell wall biosynthesis have gained more attention. Caspofungin is a member of a new class of clinically approved echinocandin drugs to treat invasive aspergillosis by blocking β-1,3-glucan synthase, thus damaging the fungal cell wall. Here, we demonstrate that caspofungin and other cell wall stressors can induce galactosaminogalactan (GAG)-dependent biofilm formation in the human pathogen Aspergillus fumigatus. We further identified SomA as a master transcription factor playing a dual role in both biofilm formation and cell wall homeostasis. SomA plays this dual role by direct binding to a conserved motif upstream of GAG biosynthetic genes and genes involved in cell wall stress sensors, chitin synthases, and β-1,3-glucan synthase. Collectively, these findings reveal a transcriptional control pathway that integrates biofilm formation and cell wall homeostasis and suggest SomA as an attractive target for antifungal drug development.

scholarly journals Species-Specific Immunological Reactivities Depend on the Cell-Wall Organization of the Two Aspergillus, Aspergillus fumigatus and A. flavus

2021 ◽  
Vol 11 ◽  
Author(s):  
Sarah Sze Wah Wong ◽  
Lakshmi Prabha Venugopalan ◽  
Audrey Beaussart ◽  
Anupama Karnam ◽  
Mohammed Razeeth Shait Mohammed ◽  
...  
Keyword(s):  
Cell Wall ◽  
Aspergillus Fumigatus ◽  
Inflammatory Responses ◽  
Treatment Strategies ◽  
Specific Treatment ◽  
Antifungal Drugs ◽  
Cell Wall Polysaccharides ◽  
Superficial Infection ◽  
Species Specific

Although belong to the same genus, Aspergillus fumigatus is primarily involved in invasive pulmonary infection, whereas Aspergillus flavus is a common cause of superficial infection. In this study, we compared conidia (the infective propagules) of these two Aspergillus species. In immunocompetent mice, intranasal inoculation with conidia of A. flavus resulted in significantly higher inflammatory responses in the lungs compared to mice inoculated with A. fumigatus conidia. In vitro assays revealed that the dormant conidia of A. flavus, unlike A. fumigatus dormant conidia, are immunostimulatory. The conidial surface of A. fumigatus was covered by a rodlet-layer, while that of A. flavus were presented with exposed polysaccharides. A. flavus harbored significantly higher number of proteins in its conidial cell wall compared to A. fumigatus conidia. Notably, β-1,3-glucan in the A. flavus conidial cell-wall showed significantly higher percentage of branching compared to that of A. fumigatus. The polysaccharides ensemble of A. flavus conidial cell wall stimulated the secretion of proinflammatory cytokines, and conidial cell wall associated proteins specifically stimulated IL-8 secretion from the host immune cells. Furthermore, the two species exhibited different sensitivities to antifungal drugs targeting cell wall polysaccharides, proposing the efficacy of species-specific treatment strategies. Overall, the species-specific organization of the conidial cell wall could be important in establishing infection by the two Aspergillus species.

scholarly journals M-ficolin is present in Aspergillus fumigatus infected lung and modulates epithelial cell immune responses elicited by fungal cell wall polysaccharides

Virulence ◽  
2017 ◽  
Vol 8 (8) ◽  
pp. 1870-1879 ◽  
Author(s):  
Kasper Jensen ◽  
Kit P. Lund ◽  
Kimmie B. Christensen ◽  
Anne T. Holm ◽  
Lalit Kumar Dubey ◽  
...  
Keyword(s):  
Cell Wall ◽  
Epithelial Cell ◽  
Immune Responses ◽  
Aspergillus Fumigatus ◽  
Fungal Cell Wall ◽  
Cell Wall Polysaccharides ◽  
Fungal Cell

scholarly journals The Paradoxical Effect of Echinocandins in Aspergillus fumigatus Relies on Recovery of the β-1,3-Glucan Synthase Fks1

2016 ◽  
Vol 61 (2) ◽  
Author(s):  
Veronika Loiko ◽  
Johannes Wagener
Keyword(s):  
Cell Wall ◽  
Aspergillus Fumigatus ◽  
Minor Importance ◽  
Initial Growth ◽  
Paradoxical Effect ◽  
Fungal Cell ◽  
Glucan Synthase ◽  
Content Type ◽  
Drug Concentrations ◽  
Very High

ABSTRACT Echinocandins target the fungal cell wall by inhibiting biosynthesis of the cell wall carbohydrate β-1,3-glucan. This antifungal drug class exhibits a paradoxical effect that is characterized by the resumption of growth of otherwise susceptible strains at higher drug concentrations (approximately 4 to 32 μg/ml). The nature of this phenomenon is still unknown. In this study, we analyzed the paradoxical effect of the echinocandin caspofungin on the pathogenic mold Aspergillus fumigatus. Using a conditional fks1 mutant, we show that very high caspofungin concentrations exert an additional antifungal activity besides inhibition of the β-1,3-glucan synthase. This activity could explain the suppression of paradoxical growth at very high caspofungin concentrations. Additionally, we found that exposure to inhibitory caspofungin concentrations always causes initial growth deprivation independently of the capability of the drug concentration to induce the paradoxical effect. Paradoxically growing hyphae emerge from microcolonies essentially devoid of β-1,3-glucan. However, these hyphae expose β-1,3-glucan again, suggesting that β-1,3-glucan synthesis is restored. In agreement with this hypothesis, we found that expression of the β-1,3-glucan synthase Fks1 is an essential requirement for the paradoxical effect. Surprisingly, overexpression of fks1 renders A. fumigatus more susceptible, whereas reduced expression leads to hyphae that are more resistant to the growth-inhibitory and limited fungicidal activity of caspofungin. Upregulation of chitin synthesis appears to be of minor importance for the paradoxical effect, since paradoxically growing hyphae exhibit significantly less chitin than the growth-deprived parental microcolonies. Our results argue for a model where the paradoxical effect primarily relies on recovery of β-1,3-glucan synthase activity.

scholarly journals Biosynthesis of β-(1→5)-Galactofuranosyl Chains of Fungal-Type and O-Mannose-Type Galactomannans within the Invasive Pathogen Aspergillus fumigatus

2019 ◽  
Author(s):  
Yuria Chihara ◽  
Yutaka Tanaka ◽  
Minoru Izumi ◽  
Daisuke Hagiwara ◽  
Akira Watanabe ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Surface ◽  
Aspergillus Fumigatus ◽  
Pathogenic Fungus ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Wall Structure ◽  
Fungal Cell ◽  
Animal Pathogens

ABSTRACTThe pathogenic fungus Aspergillus fumigatus contains galactomannans localized on the surface layer of its cell walls, which are involved in various biological processes. Galactomannans comprise α-(1→2)-/α-(1→6)-mannan and β-(1→5)-/β-(1→6)-galactofuranosyl chains. We previously revealed that GfsA is a β-galactofuranoside β-(1→5)-galactofuranosyltransferase involved in the biosynthesis of β-(1→5)-galactofuranosyl chains. Here, we clarified the entire biosynthesis of β-(1→5)-galactofuranosyl chains in A. fumigatgus. Two paralogs exist within A. fumigatus: GfsB and GfsC. We show that GfsB and GfsC, in addition to GfsA, are β-galactofuranoside β-(1→5)-galactofuranosyltransferases by biochemical and genetic analyses. GfsA, GfsB, and GfsC can synthesize β-(1→5)-galactofuranosyl oligomers up to lengths of 7, 3, and 5 galactofuranoses within an established in vitro highly efficient assay of galactofuranosyltransferase activity. Structural analyses of galactomannans extracted from the strains ΔgfsB, ΔgfsC, ΔgfsAC, and ΔgfsABC revealed that GfsA and GfsC synthesized all β-(1→5)-galactofuranosyl residues of fungal-type and O-mannose-type galactomannans, and GfsB exhibited limited function in A. fumigatus. The loss of β-(1→5)-galactofuranosyl residues decreased the hyphal growth rate and conidia formation ability as well as increased the abnormal hyphal branching structure and cell surface hydrophobicity, but this loss is dispensable for sensitivity to antifungal agents and virulence toward immune-compromised mice.IMPORTANCEβ-(1→5)-galactofuranosyl residues are widely distributed in the subphylum Pezisomycotina of the phylum Ascomycota. Pezizomycotina includes many plant and animal pathogens. Although the structure of β-(1→5)-galactofuranosyl residues of galactomannans in filamentous fungi was discovered long ago, it remains unclear which enzyme is responsible for biosynthesis of this glycan. Fungal cell wall formation processes are complicated, and information concerning glycosyltransferases is essential for their understanding. In this study, we show that GfsA and GfsC are responsible for the biosynthesis of all β-(1→5)-galactofuranosyl residues of fungal-type and O-mannose-type galactomannans. The data presented here indicates that β-(1→5)-galactofuranosyl residues are involved in cell growth, conidiation, polarity, and cell surface hydrophobicity. Our new understanding of β-(1→5)-galactofuranosyl residue biosynthesis provides important novel insights into the formation of the complex cell wall structure and the virulence of the subphylum Pezisomycotina.

scholarly journals A Report on Fungal (1→3)-α-d-glucans: Properties, Functions and Application

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3972 ◽  
Author(s):  
Katarzyna Złotko ◽  
Adrian Wiater ◽  
Adam Waśko ◽  
Małgorzata Pleszczyńska ◽  
Roman Paduch ◽  
...  
Keyword(s):  
Cell Wall ◽  
Immune System ◽  
Physicochemical Properties ◽  
Aspergillus Fumigatus ◽  
Cell Walls ◽  
Practical Application ◽  
Fungal Cell ◽  
Plant Infection ◽  
Potential Use

The cell walls of fungi are composed of glycoproteins, chitin, and α- and β-glucans. Although there are many reports on β-glucans, α-glucan polysaccharides are not yet fully understood. This review characterizes the physicochemical properties and functions of (1→3)-α-d-glucans. Particular attention has been paid to practical application and the effect of glucans in various respects, taking into account unfavourable effects and potential use. The role of α-glucans in plant infection has been proven, and collected facts have confirmed the characteristics of Aspergillus fumigatus infection associated with the presence of glucan in fungal cell wall. Like β-glucans, there are now evidence that α-glucans can also stimulate the immune system. Moreover, α-d-glucans have the ability to induce mutanases and can thus decompose plaque.

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