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Venugopalan LP, Aimanianda V, Namperumalsamy VP, Prajna L, Kuppamuthu D, Jayapal JM. Comparative proteome analysis identifies species-specific signature proteins in Aspergillus pathogens. Appl Microbiol Biotechnol 2023:10.1007/s00253-023-12559-4. [PMID: 37166481 DOI: 10.1007/s00253-023-12559-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 04/22/2023] [Accepted: 04/25/2023] [Indexed: 05/12/2023]
Abstract
Aspergillus flavus and Aspergillus fumigatus are important human pathogens that can infect the lung and cornea. During infection, Aspergillus dormant conidia are the primary morphotype that comes in contact with the host. As the conidial surface-associated proteins (CSPs) and the extracellular proteins during the early stages of growth play a crucial role in establishing infection, we profiled and compared these proteins between a clinical strain of A. flavus and a clinical strain of A. fumigatus. We identified nearly 100 CSPs in both Aspergillus, and these non-covalently associated surface proteins were able to stimulate the neutrophils to secrete interleukin IL-8. Mass spectrometry analysis identified more than 200 proteins in the extracellular space during the early stages of conidial growth and germination (early exoproteome). The conidial surface proteins and the early exoproteome of A. fumigatus were enriched with immunoreactive proteins and those with pathogenicity-related functions while that of the A. flavus were primarily enzymes involved in cell wall reorganization and binding. Comparative proteome analysis of the CSPs and the early exoproteome between A. flavus and A. fumigatus enabled the identification of a common core proteome and potential species-specific signature proteins. Transcript analysis of selected proteins indicate that the transcript-protein level correlation does not exist for all proteins and might depend on factors such as membrane-anchor signals and protein half-life. The probable signature proteins of A. flavus and A. fumigatus identified in this study can serve as potential candidates for developing species-specific diagnostic tests. KEY POINTS: • CSPs and exoproteins could differentiate A. flavus and A. fumigatus. • A. fumigatus conidial surface harbored more antigenic proteins than A. flavus. • Identified species-specific signature proteins of A. flavus and A. fumigatus.
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Affiliation(s)
- Lakshmi Prabha Venugopalan
- Department of Proteomics, Aravind Medical Research Foundation, Anna Nagar, Madurai, Tamil Nadu, India
- Present address: Centre for Biotechnology, Anna University, Chennai, India
| | - Vishukumar Aimanianda
- Unité des Aspergillus, Institut Pasteur, 75015, Paris, France
- Present address: Unité de recherche Mycologie Moléculaire, UMR2000, Institut Pasteur, 75015, Paris, France
| | | | - Lalitha Prajna
- Department of Ocular Microbiology, Aravind Medical Research Foundation, Anna Nagar, Madurai, Tamil Nadu, India
| | - Dharmalingam Kuppamuthu
- Department of Proteomics, Aravind Medical Research Foundation, Anna Nagar, Madurai, Tamil Nadu, India
| | - Jeya Maheshwari Jayapal
- Department of Proteomics, Aravind Medical Research Foundation, Anna Nagar, Madurai, Tamil Nadu, India.
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Novel Treatment Approach for Aspergilloses by Targeting Germination. J Fungi (Basel) 2022; 8:jof8080758. [PMID: 35893126 PMCID: PMC9331470 DOI: 10.3390/jof8080758] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/03/2022] [Accepted: 07/19/2022] [Indexed: 12/24/2022] Open
Abstract
Germination of conidia is an essential process within the Aspergillus life cycle and plays a major role during the infection of hosts. Conidia are able to avoid detection by the majority of leukocytes when dormant. Germination can cause severe health problems, specifically in immunocompromised people. Aspergillosis is most often caused by Aspergillus fumigatus (A. fumigatus) and affects neutropenic patients, as well as people with cystic fibrosis (CF). These patients are often unable to effectively detect and clear the conidia or hyphae and can develop chronic non-invasive and/or invasive infections or allergic inflammatory responses. Current treatments with (tri)azoles can be very effective to combat a variety of fungal infections. However, resistance against current azoles has emerged and has been increasing since 1998. As a consequence, patients infected with resistant A. fumigatus have a reported mortality rate of 88% to 100%. Especially with the growing number of patients that harbor azole-resistant Aspergilli, novel antifungals could provide an alternative. Aspergilloses differ in defining characteristics, but germination of conidia is one of the few common denominators. By specifically targeting conidial germination with novel antifungals, early intervention might be possible. In this review, we propose several morphotypes to disrupt conidial germination, as well as potential targets. Hopefully, new antifungals against such targets could contribute to disturbing the ability of Aspergilli to germinate and grow, resulting in a decreased fungal burden on patients.
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Huang H, Zhang X, Zhang Y, Yi G, Xie J, Viljoen A, Wang W, Mostert D, Fu G, Peng C, Xiang D, Li C, Liu S. FocECM33, a GPI-anchored protein, regulates vegetative growth and virulence in Fusarium oxysporum f. sp. cubense tropical race 4. Fungal Biol 2022; 126:213-223. [DOI: 10.1016/j.funbio.2021.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 09/21/2021] [Accepted: 12/24/2021] [Indexed: 11/04/2022]
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GPI Anchored Proteins in Aspergillus fumigatus and Cell Wall Morphogenesis. Curr Top Microbiol Immunol 2020; 425:167-186. [PMID: 32418035 DOI: 10.1007/82_2020_207] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Glycosylphosphatidylinositol (GPI) anchored proteins are a class of proteins attached to the extracellular leaflet of the plasma membrane via a post-translational modification, the glycolipid anchor. GPI anchored proteins are expressed in all eukaryotes, from fungi to plants and animals. They display very diverse functions ranging from enzymatic activity, signaling, cell adhesion, cell wall metabolism, and immune response. In this review, we investigated for the first time an exhaustive list of all the GPI anchored proteins present in the Aspergillus fumigatus genome. An A. fumigatus mutant library of all the genes that encode in silico identified GPI anchored proteins has been constructed and the phenotypic analysis of all these mutants has been characterized including their growth, conidial viability or morphology, adhesion and the ability to form biofilms. We showed the presence of different fungal categories of GPI anchored proteins in the A. fumigatus genome associated to their role in cell wall remodeling, adhesion, and biofilm formation.
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Pérez-Llano Y, Rodríguez-Pupo EC, Druzhinina IS, Chenthamara K, Cai F, Gunde-Cimerman N, Zalar P, Gostinčar C, Kostanjšek R, Folch-Mallol JL, Batista-García RA, Sánchez-Carbente MDR. Stress Reshapes the Physiological Response of Halophile Fungi to Salinity. Cells 2020; 9:E525. [PMID: 32106416 PMCID: PMC7140475 DOI: 10.3390/cells9030525] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/12/2020] [Accepted: 02/19/2020] [Indexed: 11/16/2022] Open
Abstract
(1) Background: Mechanisms of cellular and molecular adaptation of fungi to salinity have been commonly drawn from halotolerant strains and few studies in basidiomycete fungi. These studies have been conducted in settings where cells are subjected to stress, either hypo- or hyperosmotic, which can be a confounding factor in describing physiological mechanisms related to salinity. (2) Methods: We have studied transcriptomic changes in Aspergillussydowii, a halophilic species, when growing in three different salinity conditions (No NaCl, 0.5 M, and 2.0 M NaCl). (3) Results: In this fungus, major physiological modifications occur under high salinity (2.0 M NaCl) and not when cultured under optimal conditions (0.5 M NaCl), suggesting that most of the mechanisms described for halophilic growth are a consequence of saline stress response and not an adaptation to saline conditions. Cell wall modifications occur exclusively at extreme salinity, with an increase in cell wall thickness and lamellar structure, which seem to involve a decrease in chitin content and an augmented content of alfa and beta-glucans. Additionally, three hydrophobin genes were differentially expressed under hypo- or hyperosmotic stress but not when the fungus grows optimally. Regarding compatible solutes, glycerol is the main compound accumulated in salt stress conditions, whereas trehalose is accumulated in the absence of salt. (4) Conclusions: Physiological responses to salinity vary greatly between optimal and high salt concentrations and are not a simple graded effect as the salt concentration increases. Our results highlight the influence of stress in reshaping the response of extremophiles to environmental challenges.
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Affiliation(s)
- Yordanis Pérez-Llano
- Center of Research on Cell Dynamics, Autonomous University of the State of Morelos, Morelos 62210, Mexico; (Y.P.-L.); (E.C.R.-P.)
| | - Eya Caridad Rodríguez-Pupo
- Center of Research on Cell Dynamics, Autonomous University of the State of Morelos, Morelos 62210, Mexico; (Y.P.-L.); (E.C.R.-P.)
| | - Irina S. Druzhinina
- Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, 1060 Vienna, Austria; (I.S.D.); (K.C.); (F.C.)
- Fungal Genomics Group, Nanjing Agricultural University, Nanjing 210095, China
| | - Komal Chenthamara
- Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, 1060 Vienna, Austria; (I.S.D.); (K.C.); (F.C.)
| | - Feng Cai
- Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, 1060 Vienna, Austria; (I.S.D.); (K.C.); (F.C.)
- Fungal Genomics Group, Nanjing Agricultural University, Nanjing 210095, China
| | - Nina Gunde-Cimerman
- Department of Biology, Biotechnical Faculty, University of Ljubljana, SI-1000 Ljubljana, Slovenia; (N.G.-C.); (P.Z.); (C.G.); (R.K.)
| | - Polona Zalar
- Department of Biology, Biotechnical Faculty, University of Ljubljana, SI-1000 Ljubljana, Slovenia; (N.G.-C.); (P.Z.); (C.G.); (R.K.)
| | - Cene Gostinčar
- Department of Biology, Biotechnical Faculty, University of Ljubljana, SI-1000 Ljubljana, Slovenia; (N.G.-C.); (P.Z.); (C.G.); (R.K.)
| | - Rok Kostanjšek
- Department of Biology, Biotechnical Faculty, University of Ljubljana, SI-1000 Ljubljana, Slovenia; (N.G.-C.); (P.Z.); (C.G.); (R.K.)
| | - Jorge Luis Folch-Mallol
- Laboratory of Molecular Biology of Fungi, Center for Research on Biotechnology, Autonomous University of the State of Morelos, Morelos 62210, Mexico;
| | - Ramón Alberto Batista-García
- Center of Research on Cell Dynamics, Autonomous University of the State of Morelos, Morelos 62210, Mexico; (Y.P.-L.); (E.C.R.-P.)
| | - María del Rayo Sánchez-Carbente
- Laboratory of Molecular Biology of Fungi, Center for Research on Biotechnology, Autonomous University of the State of Morelos, Morelos 62210, Mexico;
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Abstract
Aspergilli produce conidia for reproduction or to survive hostile conditions, and they are highly effective in the distribution of conidia through the environment. In immunocompromised individuals, inhaled conidia can germinate inside the respiratory tract, which may result in invasive pulmonary aspergillosis. The management of invasive aspergillosis has become more complex, with new risk groups being identified and the emergence of antifungal resistance. Patient survival is threatened by these developments, stressing the need for alternative therapeutic strategies. As germination is crucial for infection, prevention of this process might be a feasible approach. A broader understanding of conidial germination is important to identify novel antigermination targets. In this review, we describe conidial resistance against various stresses, transition from dormant conidia to hyphal growth, the underlying molecular mechanisms involved in germination of the most common Aspergillus species, and promising antigermination targets. Germination of Aspergillus is characterized by three morphotypes: dormancy, isotropic growth, and polarized growth. Intra- and extracellular proteins play an important role in the protection against unfavorable environmental conditions. Isotropically expanding conidia remodel the cell wall, and biosynthetic machineries are needed for cellular growth. These biosynthetic machineries are also important during polarized growth, together with tip formation and the cell cycle machinery. Genes involved in isotropic and polarized growth could be effective antigermination targets. Transcriptomic and proteomic studies on specific Aspergillus morphotypes will improve our understanding of the germination process and allow discovery of novel antigermination targets and biomarkers for early diagnosis and therapy.
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Souza JAM, Baltazar LDM, Carregal VM, Gouveia-Eufrasio L, de Oliveira AG, Dias WG, Campos Rocha M, Rocha de Miranda K, Malavazi I, Santos DDA, Frézard FJG, de Souza DDG, Teixeira MM, Soriani FM. Characterization of Aspergillus fumigatus Extracellular Vesicles and Their Effects on Macrophages and Neutrophils Functions. Front Microbiol 2019; 10:2008. [PMID: 31551957 PMCID: PMC6738167 DOI: 10.3389/fmicb.2019.02008] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 08/16/2019] [Indexed: 12/26/2022] Open
Abstract
Extracellular vesicles (EVs) has been considered an alternative process for intercellular communication. EVs release by filamentous fungi and the role of vesicular secretion during fungus-host cells interaction remain unknown. Here, we identified the secretion of EVs from the pathogenic filamentous fungus, Aspergillus fumigatus. Analysis of the structure of EVs demonstrated that A. fumigatus produces round shaped bilayer structures ranging from 100 to 200 nm size, containing ergosterol and a myriad of proteins involved in REDOX, cell wall remodeling and metabolic functions of the fungus. We demonstrated that macrophages can phagocytose A. fumigatus EVs. Phagocytic cells, stimulated with EVs, increased fungal clearance after A. fumigatus conidia challenge. EVs were also able to induce the production of TNF-α and CCL2 by macrophages and a synergistic effect was observed in the production of these mediators when the cells were challenged with the conidia. In bone marrow-derived neutrophils (BMDN) treated with EVs, there was enhancement of the production of TNF-α and IL-1β in response to conidia. Together, our results demonstrate, for the first time, that A. fumigatus produces EVs containing a diverse set of proteins involved in fungal physiology and virulence. Moreover, EVs are biologically active and stimulate production of inflammatory mediators and fungal clearance.
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Affiliation(s)
- Jéssica Amanda Marques Souza
- Centro de Pesquisa e Desenvolvimento de Fármacos, Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Ludmila de Matos Baltazar
- Laboratório de Interação Microrganismo-Hospedeiro, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Virgínia Mendes Carregal
- Laboratório de Biofísica e Sistemas Nanoestruturados, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Ludmila Gouveia-Eufrasio
- Laboratório de Micologia, Departamento de Microbiologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - André Gustavo de Oliveira
- Lab Circuitos Fisiológicos, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Wendell Girard Dias
- Plataforma de Microscopia Eletrônica Rudolf Barth, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Marina Campos Rocha
- Centro de Ciências Biológicas e da Saúde, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, Brazil
| | - Kildare Rocha de Miranda
- Laboratório de Ultraestrutura Celular Hertha Meyer, Programa de Biologia Celular e Parasitologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Iran Malavazi
- Centro de Ciências Biológicas e da Saúde, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, Brazil
| | - Daniel de Assis Santos
- Laboratório de Micologia, Departamento de Microbiologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Frédéric Jean Georges Frézard
- Laboratório de Biofísica e Sistemas Nanoestruturados, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Daniele da Glória de Souza
- Laboratório de Interação Microrganismo-Hospedeiro, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Mauro Martins Teixeira
- Centro de Pesquisa e Desenvolvimento de Fármacos, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Frederico Marianetti Soriani
- Centro de Pesquisa e Desenvolvimento de Fármacos, Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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8
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Muszkieta L, Fontaine T, Beau R, Mouyna I, Vogt MS, Trow J, Cormack BP, Essen LO, Jouvion G, Latgé JP. The Glycosylphosphatidylinositol-Anchored DFG Family Is Essential for the Insertion of Galactomannan into the β-(1,3)-Glucan-Chitin Core of the Cell Wall of Aspergillus fumigatus. mSphere 2019; 4:e00397-19. [PMID: 31366710 PMCID: PMC6669337 DOI: 10.1128/msphere.00397-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 06/25/2019] [Indexed: 11/20/2022] Open
Abstract
The fungal cell wall is a complex and dynamic entity essential for the development of fungi. It is composed mainly of polysaccharides that are synthetized by protein complexes. At the cell wall level, enzyme activities are involved in postsynthesis polysaccharide modifications such as cleavage, elongation, branching, and cross-linking. Glycosylphosphatidylinositol (GPI)-anchored proteins have been shown to participate in cell wall biosynthesis and specifically in polysaccharide remodeling. Among these proteins, the DFG family plays an essential role in controlling polar growth in yeast. In the filamentous fungus and opportunistic human pathogen Aspergillus fumigatus, the DFG gene family contains seven orthologous DFG genes among which only six are expressed under in vitro growth conditions. Deletions of single DFG genes revealed that DFG3 plays the most important morphogenetic role in this gene family. A sextuple-deletion mutant resulting from the deletion of all in vitro expressed DFG genes did not contain galactomannan in the cell wall and has severe growth defects. This study has shown that DFG members are absolutely necessary for the insertion of galactomannan into the cell wall of A. fumigatus and that the proper cell wall localization of the galactomannan is essential for correct fungal morphogenesis in A. fumigatusIMPORTANCE The fungal cell wall is a complex and dynamic entity essential for the development of fungi. It is composed mainly of polysaccharides that are synthetized by protein complexes. Enzymes involved in postsynthesis polysaccharide modifications, such as cleavage, elongation, branching, and cross-linking, are essential for fungal life. Here, we investigated in Aspergillus fumigatus the role of the members of the Dfg family, one of the 4 GPI-anchored protein families common to yeast and molds involved in cell wall remodeling. Molecular and biochemical approaches showed that DFG members are required for filamentous growth, conidiation, and cell wall organization and are essential for the life of this fungal pathogen.
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Affiliation(s)
| | | | - Rémi Beau
- Unité des Aspergillus, Institut Pasteur, Paris, France
| | | | | | - Jonathan Trow
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Brendan P Cormack
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Lars-Oliver Essen
- Faculty of Chemistry, Philipps-Universität Marburg, Marburg, Germany
| | - Gregory Jouvion
- Histopathologie humaine et modèles animaux, Institut Pasteur, Paris, France
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9
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Fabri JHTM, Rocha MC, Malavazi I. Overview of the Interplay Between Cell Wall Integrity Signaling Pathways and Membrane Lipid Biosynthesis in Fungi: Perspectives for Aspergillus fumigatus. Curr Protein Pept Sci 2019; 21:265-283. [PMID: 31284857 DOI: 10.2174/1389203720666190705164203] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 06/10/2019] [Accepted: 06/13/2019] [Indexed: 11/22/2022]
Abstract
The cell wall (CW) and plasma membrane are fundamental structures that define cell shape and support different cellular functions. In pathogenic fungi, such as Aspegillus fumigatus, they not only play structural roles but are also important for virulence and immune recognition. Both the CW and the plasma membrane remain as attractive drug targets to treat fungal infections, such as the Invasive Pulmonary Aspergillosis (IPA), a disease associated with high morbimortality in immunocompromised individuals. The low efficiency of echinocandins that target the fungal CW biosynthesis, the occurrence of environmental isolates resistant to azoles such as voriconazole and the known drawbacks associated with amphotericin toxicity foster the urgent need for fungal-specific drugable targets and/or more efficient combinatorial therapeutic strategies. Reverse genetic approaches in fungi unveil that perturbations of the CW also render cells with increased susceptibility to membrane disrupting agents and vice-versa. However, how the fungal cells simultaneously cope with perturbation in CW polysaccharides and cell membrane proteins to allow morphogenesis is scarcely known. Here, we focus on current information on how the main signaling pathways that maintain fungal cell wall integrity, such as the Cell Wall Integrity and the High Osmolarity Glycerol pathways, in different species often cross-talk to regulate the synthesis of molecules that comprise the plasma membrane, especially sphingolipids, ergosterol and phospholipids to promote functioning of both structures concomitantly and thus, cell viability. We propose that the conclusions drawn from other organisms are the foundations to point out experimental lines that can be endeavored in A. fumigatus.
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Affiliation(s)
| | - Marina C Rocha
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, Brazil
| | - Iran Malavazi
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, Brazil
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10
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Fernando U, Chatur S, Joshi M, Thomas Bonner C, Fan T, Hubbard K, Chabot D, Rowland O, Wang L, Subramaniam R, Rampitsch C. Redox signalling from NADPH oxidase targets metabolic enzymes and developmental proteins in Fusarium graminearum. MOLECULAR PLANT PATHOLOGY 2019; 20:92-106. [PMID: 30113774 PMCID: PMC6430467 DOI: 10.1111/mpp.12742] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
NADPH oxidase (NOX) is one of the sources of reactive oxygen species (ROS) that modulates the activity of proteins through modifications of their cysteine residues. In a previous study, we demonstrated the importance of NOX in both the development and pathogenicity of the phytopathogen Fusarium graminearum. In this article, comparative proteomics between the wild-type and a Nox mutant of F. graminearum was used to identify active cysteine residues on candidate redox-sensing proteins. A two-dimensional gel approach based on labelling with monobromobimane (mBBR) identified 19 candidate proteins, and was complemented with a gel-free shotgun approach based on a biotin switch method, which yielded 99 candidates. The results indicated that, in addition to temporal regulation, a large number of primary metabolic enzymes are potentially targeted by NoxAB-generated ROS. Targeted disruption of these metabolic genes showed that, although some are dispensable, others are essential. In addition to metabolic enzymes, developmental proteins, such as the Woronin body major protein (FGSG_08737) and a glycosylphosphatidylinositol (GPI)-anchored protein (FGSG_10089), were also identified. Deletion of either of these genes reduced the virulence of F. graminearum. Furthermore, changing the redox-modified cysteine (Cys325 ) residue in FGSG_10089 to either serine or phenylalanine resulted in a similar phenotype to the FGSG_10089 knockout strain, which displayed reduced virulence and altered cell wall morphology; this underscores the importance of Cys325 to the function of the protein. Our results indicate that NOX-generated ROS act as intracellular signals in F. graminearum and modulate the activity of proteins affecting development and virulence in planta.
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Affiliation(s)
- Ursla Fernando
- Agriculture and Agrifood Canada, Morden Research & Development CentreMordenR6M 1Y5MBCanada
| | - Salima Chatur
- Agriculture and Agrifood Canada, Ottawa Research & Development CentreOttawaK1A 0C6ONCanada
| | - Manisha Joshi
- Agriculture and Agrifood Canada, Morden Research & Development CentreMordenR6M 1Y5MBCanada
- Agriculture and Agrifood Canada, Ottawa Research & Development CentreOttawaK1A 0C6ONCanada
| | - Christopher Thomas Bonner
- Agriculture and Agrifood Canada, Ottawa Research & Development CentreOttawaK1A 0C6ONCanada
- Department of BiologyCarleton UniversityOttawaK1S 5B6ONCanada
| | - Tao Fan
- Agriculture and Agrifood Canada, Morden Research & Development CentreMordenR6M 1Y5MBCanada
| | - Keith Hubbard
- Agriculture and Agrifood Canada, Ottawa Research & Development CentreOttawaK1A 0C6ONCanada
| | - Denise Chabot
- Agriculture and Agrifood Canada, Ottawa Research & Development CentreOttawaK1A 0C6ONCanada
| | - Owen Rowland
- Department of BiologyCarleton UniversityOttawaK1S 5B6ONCanada
| | - Li Wang
- Agriculture and Agrifood Canada, Ottawa Research & Development CentreOttawaK1A 0C6ONCanada
| | - Rajagopal Subramaniam
- Agriculture and Agrifood Canada, Ottawa Research & Development CentreOttawaK1A 0C6ONCanada
| | - Christof Rampitsch
- Agriculture and Agrifood Canada, Morden Research & Development CentreMordenR6M 1Y5MBCanada
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11
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Chang PK, Zhang Q, Scharfenstein L, Mack B, Yoshimi A, Miyazawa K, Abe K. Aspergillus flavus GPI-anchored protein-encoding ecm33 has a role in growth, development, aflatoxin biosynthesis, and maize infection. Appl Microbiol Biotechnol 2018; 102:5209-5220. [DOI: 10.1007/s00253-018-9012-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 04/09/2018] [Accepted: 04/10/2018] [Indexed: 12/21/2022]
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12
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Li J, Mouyna I, Henry C, Moyrand F, Malosse C, Chamot-Rooke J, Janbon G, Latgé JP, Fontaine T. Glycosylphosphatidylinositol Anchors from Galactomannan and GPI-Anchored Protein Are Synthesized by Distinct Pathways in Aspergillus fumigatus. J Fungi (Basel) 2018; 4:E19. [PMID: 29393895 PMCID: PMC5872322 DOI: 10.3390/jof4010019] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 01/12/2018] [Accepted: 01/19/2018] [Indexed: 11/16/2022] Open
Abstract
Glycosylphosphatidylinositols (GPIs) are lipid anchors allowing the exposure of proteins at the outer layer of the plasma membrane. In fungi, a number of GPI-anchored proteins (GPI-APs) are involved in the remodeling of the cell wall polymers. GPIs follow a specific biosynthetic pathway in the endoplasmic reticulum. After the transfer of the protein onto the GPI-anchor, a lipid remodeling occurs to substitute the diacylglycerol moiety by a ceramide. In addition to GPI-APs, A. fumigatus produces a GPI-anchored polysaccharide, the galactomannan (GM), that remains unique in the fungal kingdom. To investigate the role of the GPI pathway in the biosynthesis of the GM and cell wall organization, the deletion of PER1-coding for a phospholipase required for the first step of the GPI lipid remodeling-was undertaken. Biochemical characterization of the GPI-anchor isolated from GPI-APs showed that the PER1 deficient mutant produced a lipid anchor with a diacylglycerol. The absence of a ceramide on GPI-anchors in the Δper1 mutant led to a mislocation of GPI-APs and to an alteration of the composition of the cell wall alkali-insoluble fraction. On the other hand, the GM isolated from the Δper1 mutant membranes possesses a ceramide moiety as the parental strain, showing that GPI anchor of the GM follow a distinct unknown biosynthetic pathway.
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Affiliation(s)
- Jizhou Li
- Unité des Aspergillus, 25 rue du Docteur Roux, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France.
| | - Isabelle Mouyna
- Unité des Aspergillus, 25 rue du Docteur Roux, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France.
| | - Christine Henry
- Unité des Aspergillus, 25 rue du Docteur Roux, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France.
| | - Frédérique Moyrand
- Unité de Biologie des ARN des Pathogènes Fongiques, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France.
| | - Christian Malosse
- Unité de Spectrométrie de Masse pour la Biologie, Institut Pasteur, CNRS USR 2000, 28 rue du Docteur Roux, 75015 Paris, France.
| | - Julia Chamot-Rooke
- Unité de Spectrométrie de Masse pour la Biologie, Institut Pasteur, CNRS USR 2000, 28 rue du Docteur Roux, 75015 Paris, France.
| | - Guilhem Janbon
- Unité de Biologie des ARN des Pathogènes Fongiques, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France.
| | - Jean-Paul Latgé
- Unité des Aspergillus, 25 rue du Docteur Roux, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France.
| | - Thierry Fontaine
- Unité des Aspergillus, 25 rue du Docteur Roux, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France.
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Latgé JP, Beauvais A, Chamilos G. The Cell Wall of the Human Fungal Pathogen Aspergillus fumigatus: Biosynthesis, Organization, Immune Response, and Virulence. Annu Rev Microbiol 2017; 71:99-116. [PMID: 28701066 DOI: 10.1146/annurev-micro-030117-020406] [Citation(s) in RCA: 132] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
More than 90% of the cell wall of the filamentous fungus Aspergillus fumigatus comprises polysaccharides. Biosynthesis of the cell wall polysaccharides is under the control of three types of enzymes: transmembrane synthases, which are anchored to the plasma membrane and use nucleotide sugars as substrates, and cell wall-associated transglycosidases and glycosyl hydrolases, which are responsible for remodeling the de novo synthesized polysaccharides and establishing the three-dimensional structure of the cell wall. For years, the cell wall was considered an inert exoskeleton of the fungal cell. The cell wall is now recognized as a living organelle, since the composition and cellular localization of the different constitutive cell wall components (especially of the outer layers) vary when the fungus senses changes in the external environment. The cell wall plays a major role during infection. The recognition of the fungal cell wall by the host is essential in the initiation of the immune response. The interactions between the different pattern-recognition receptors (PRRs) and cell wall pathogen-associated molecular patterns (PAMPs) orientate the host response toward either fungal death or growth, which would then lead to disease development. Understanding the molecular determinants of the interplay between the cell wall and host immunity is fundamental to combatting Aspergillus diseases.
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Affiliation(s)
- Jean-Paul Latgé
- Unité des Aspergillus, Institut Pasteur, 75015 Paris, France; ,
| | - Anne Beauvais
- Unité des Aspergillus, Institut Pasteur, 75015 Paris, France; ,
| | - Georgios Chamilos
- Department of Clinical Microbiology and Microbial Pathogenesis, University of Crete, Heraklion, Crete 74100, Greece.,Institute of Molecular Biology and Biotechnology, Heraklion, Crete 70013, Greece;
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Yang Y, Chen M, Li Z, Al-Hatmi AMS, de Hoog S, Pan W, Ye Q, Bo X, Li Z, Wang S, Wang J, Chen H, Liao W. Genome Sequencing and Comparative Genomics Analysis Revealed Pathogenic Potential in Penicillium capsulatum as a Novel Fungal Pathogen Belonging to Eurotiales. Front Microbiol 2016; 7:1541. [PMID: 27761131 PMCID: PMC5051111 DOI: 10.3389/fmicb.2016.01541] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Accepted: 09/14/2016] [Indexed: 01/31/2023] Open
Abstract
Penicillium capsulatum is a rare Penicillium species used in paper manufacturing, but recently it has been reported to cause invasive infection. To research the pathogenicity of the clinical Penicillium strain, we sequenced the genomes and transcriptomes of the clinical and environmental strains of P. capsulatum. Comparative analyses of these two P. capsulatum strains and close related strains belonging to Eurotiales were performed. The assembled genome sizes of P. capsulatum are approximately 34.4 Mbp in length and encode 11,080 predicted genes. The different isolates of P. capsulatum are highly similar, with the exception of several unique genes, INDELs or SNPs in the genes coding for glycosyl hydrolases, amino acid transporters and circumsporozoite protein. A phylogenomic analysis was performed based on the whole genome data of 38 strains belonging to Eurotiales. By comparing the whole genome sequences and the virulence-related genes from 20 important related species, including fungal pathogens and non-human pathogens belonging to Eurotiales, we found meaningful pathogenicity characteristics between P. capsulatum and its closely related species. Our research indicated that P. capsulatum may be a neglected opportunistic pathogen. This study is beneficial for mycologists, geneticists and epidemiologists to achieve a deeper understanding of the genetic basis of the role of P. capsulatum as a newly reported fungal pathogen.
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Affiliation(s)
- Ying Yang
- Beijing Institute of BiotechnologyBeijing, China; Beijing Institute of Radiation MedicineBeijing, China; National Institutes for Food and Drug ControlBeijing, China
| | - Min Chen
- Department of Dermatology, Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Shanghai Changzheng HospitalShanghai, China; CBS-KNAW Fungal Biodiversity CentreUtrecht, Netherlands; Institute of Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands
| | - Zongwei Li
- Center for Hospital Infection Control, Chinese PLA Institute for Disease Control and Prevention Beijing, China
| | - Abdullah M S Al-Hatmi
- CBS-KNAW Fungal Biodiversity CentreUtrecht, Netherlands; Institute of Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands; Directorate General of Health Services, Ibri Hospital, Ministry of HealthIbri, Oman
| | - Sybren de Hoog
- CBS-KNAW Fungal Biodiversity CentreUtrecht, Netherlands; Institute of Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands
| | - Weihua Pan
- Department of Dermatology, Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Shanghai Changzheng Hospital Shanghai, China
| | - Qiang Ye
- National Institutes for Food and Drug ControlBeijing, China; Key Laboratory of the Ministry of Health for Research on Quality and Standardization of Biotech ProductsBeijing, China
| | - Xiaochen Bo
- Beijing Institute of Radiation Medicine Beijing, China
| | - Zhen Li
- Beijing Institute of Radiation Medicine Beijing, China
| | - Shengqi Wang
- Beijing Institute of Radiation Medicine Beijing, China
| | - Junzhi Wang
- National Institutes for Food and Drug Control Beijing, China
| | - Huipeng Chen
- Beijing Institute of Biotechnology Beijing, China
| | - Wanqing Liao
- Department of Dermatology, Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Shanghai Changzheng Hospital Shanghai, China
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Latgé JP. 30 years of battling the cell wall. Med Mycol 2016; 55:4-9. [DOI: 10.1093/mmy/myw076] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 05/27/2016] [Accepted: 07/28/2016] [Indexed: 11/13/2022] Open
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16
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Volke-Sepulveda T, Salgado-Bautista D, Bergmann C, Wells L, Gutierrez-Sanchez G, Favela-Torres E. Secretomic Insight into Glucose Metabolism of Aspergillus brasiliensis in Solid-State Fermentation. J Proteome Res 2016; 15:3856-3871. [PMID: 27548361 DOI: 10.1021/acs.jproteome.6b00663] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The genus Aspergillus is ubiquitous in nature and includes various species extensively exploited industrially due to their ability to produce and secrete a variety of enzymes and metabolites. Most processes are performed in submerged fermentation (SmF); however, solid-state fermentation (SSF) offers several advantages, including lower catabolite repression and substrate inhibition and higher productivity and stability of the enzymes produced. This study aimed to explain the improved metabolic behavior of A. brasiliensis ATCC9642 in SSF at high glucose concentrations through a proteomic approach. Online respirometric analysis provided reproducible samples for secretomic studies when the maximum CO2 production rate occurred, ensuring consistent physiological states. Extracellular extracts from SSF cultures were treated by SDS-PAGE, digested with trypsin, and analyzed by LC-MS/MS. Of 531 sequences identified, 207 proteins were analyzed. Twenty-five were identified as the most abundant unregulated proteins; 87 were found to be up-regulated and 95 were down-regulated with increasing glucose concentration. Of the regulated proteins, 120 were enzymes, most involved in the metabolism of carbohydrates (51), amino acids (23), and nucleotides (9). This study shows the high protein secretory activity of A. brasiliensis under SSF conditions. High glucose concentration favors catabolic activities, while some stress-related proteins and those involved in proteolysis are down-regulated.
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Affiliation(s)
- Tania Volke-Sepulveda
- Departamento de Biotecnología, Universidad Autónoma Metropolitana-Iztapalapa , San Rafael Atlixco 186, Col. Vicentina, Distrito Federal, C.P. 09340, México
| | - Daniel Salgado-Bautista
- Departamento de Biotecnología, Universidad Autónoma Metropolitana-Iztapalapa , San Rafael Atlixco 186, Col. Vicentina, Distrito Federal, C.P. 09340, México
| | - Carl Bergmann
- Complex Carbohydrate Research Center , 315 Riverbend Road, Athens, Georgia 30605, United States
| | - Lance Wells
- Complex Carbohydrate Research Center , 315 Riverbend Road, Athens, Georgia 30605, United States
| | | | - Ernesto Favela-Torres
- Departamento de Biotecnología, Universidad Autónoma Metropolitana-Iztapalapa , San Rafael Atlixco 186, Col. Vicentina, Distrito Federal, C.P. 09340, México
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17
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Liu L, Free SJ. Characterization of the Sclerotinia sclerotiorum cell wall proteome. MOLECULAR PLANT PATHOLOGY 2016; 17:985-95. [PMID: 26661933 PMCID: PMC6638348 DOI: 10.1111/mpp.12352] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 11/30/2015] [Accepted: 12/03/2015] [Indexed: 05/20/2023]
Abstract
We used a proteomic analysis to identify cell wall proteins released from Sclerotinia sclerotiorum hyphal and sclerotial cell walls via a trifluoromethanesulfonic acid (TFMS) digestion. Cell walls from hyphae grown in Vogel's glucose medium (a synthetic medium lacking plant materials), from hyphae grown in potato dextrose broth and from sclerotia produced on potato dextrose agar were used in the analysis. Under the conditions used, TFMS digests the glycosidic linkages in the cell walls to release intact cell wall proteins. The analysis identified 24 glycosylphosphatidylinositol (GPI)-anchored cell wall proteins and 30 non-GPI-anchored cell wall proteins. We found that the cell walls contained an array of cell wall biosynthetic enzymes similar to those found in the cell walls of other fungi. When comparing the proteins in hyphal cell walls grown in potato dextrose broth with those in hyphal cell walls grown in the absence of plant material, it was found that a core group of cell wall biosynthetic proteins and some proteins associated with pathogenicity (secreted cellulases, pectin lyases, glucosidases and proteases) were expressed in both types of hyphae. The hyphae grown in potato dextrose broth contained a number of additional proteins (laccases, oxalate decarboxylase, peroxidase, polysaccharide deacetylase and several proteins unique to Sclerotinia and Botrytis) that might facilitate growth on a plant host. A comparison of the proteins in the sclerotial cell wall with the proteins in the hyphal cell wall demonstrated that sclerotia formation is not marked by a major shift in the composition of cell wall protein. We found that the S. sclerotiorum cell walls contained 11 cell wall proteins that were encoded only in Sclerotinia and Botrytis genomes.
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Affiliation(s)
- Longzhou Liu
- Shanghai Academy of Agricultural Sciences, Shanghai, 200210, China
| | - Stephen J Free
- Department of Biological Sciences, SUNY University at Buffalo, Buffalo, NY, 14260, USA
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18
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Dieryckx C, Gaudin V, Dupuy JW, Bonneu M, Girard V, Job D. Beyond plant defense: insights on the potential of salicylic and methylsalicylic acid to contain growth of the phytopathogen Botrytis cinerea. FRONTIERS IN PLANT SCIENCE 2015; 6:859. [PMID: 26528317 PMCID: PMC4607878 DOI: 10.3389/fpls.2015.00859] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 09/29/2015] [Indexed: 05/27/2023]
Abstract
Using Botrytis cinerea we confirmed in the present work several previous studies showing that salicylic acid, a main plant hormone, inhibits fungal growth in vitro. Such an inhibitory effect was also observed for the two salicylic acid derivatives, methylsalicylic and acetylsalicylic acid. In marked contrast, 5-sulfosalicylic acid was totally inactive. Comparative proteomics from treated vs. control mycelia showed that both the intracellular and extracellular proteomes were affected in the presence of salicylic acid or methylsalicylic acid. These data suggest several mechanisms that could potentially account for the observed fungal growth inhibition, notably pH regulation, metal homeostasis, mitochondrial respiration, ROS accumulation and cell wall remodeling. The present observations support a role played by the phytohormone SA and derivatives in directly containing the pathogen. Data are available via ProteomeXchange with identifier PXD002873.
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Affiliation(s)
- Cindy Dieryckx
- Laboratoire Mixte UMR 5240, Plateforme de Protéomique, Centre National de la Recherche ScientifiqueLyon, France
| | - Vanessa Gaudin
- Laboratoire Mixte UMR 5240, Plateforme de Protéomique, Centre National de la Recherche ScientifiqueLyon, France
| | - Jean-William Dupuy
- Plateforme Protéome, Centre de Génomique Fonctionnelle, Université de BordeauxBordeaux, France
| | - Marc Bonneu
- Plateforme Protéome, Centre de Génomique Fonctionnelle, Université de BordeauxBordeaux, France
| | - Vincent Girard
- Laboratoire Mixte UMR 5240, Plateforme de Protéomique, Centre National de la Recherche ScientifiqueLyon, France
| | - Dominique Job
- Laboratoire Mixte UMR 5240, Plateforme de Protéomique, Centre National de la Recherche ScientifiqueLyon, France
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19
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Chen Y, Zhu J, Ying SH, Feng MG. The GPI-anchored protein Ecm33 is vital for conidiation, cell wall integrity, and multi-stress tolerance of two filamentous entomopathogens but not for virulence. Appl Microbiol Biotechnol 2014; 98:5517-29. [DOI: 10.1007/s00253-014-5577-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 01/19/2014] [Accepted: 01/21/2014] [Indexed: 01/19/2023]
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20
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One single basic amino acid at the ω-1 or ω-2 site is a signal that retains glycosylphosphatidylinositol-anchored protein in the plasma membrane of Aspergillus fumigatus. EUKARYOTIC CELL 2013; 12:889-99. [PMID: 23584992 DOI: 10.1128/ec.00351-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Although the plasma membrane is the terminal destination for glycosylphosphatidylinositol (GPI) proteins in higher eukaryotes, cell wall-attached GPI proteins (GPI-CWPs) are found in many fungal species. In yeast, some of the cis-requirements directing localization of GPI proteins to the plasma membrane or cell wall are now understood. However, it remains to be determined how Aspergillus fumigatus, an opportunistic fungal pathogen, signals, and sorts GPI proteins to either the plasma membrane or the cell wall. In this study, chimeric green fluorescent proteins (GFPs) were constructed as fusions with putative C-terminal GPI signal sequences from A. fumigatus Mp1p, Gel1p, and Ecm33p, as well as site-directed mutations thereof. By analyzing cellular localization of chimeric GFPs using Western blotting, electron microscopy, and fluorescence microscopy, we showed that, in contrast to yeast, a single Lys residue at the ω-1 or ω-2 site alone could retain GPI-anchored GFP in the plasma membrane. Although the signal for cell wall distribution has not been identified yet, it appeared that the threonine/serine-rich region at the C-terminal half of AfMp1 was not required for cell wall distribution. Based on our results, the cis-requirements directing localization of GPI proteins in A. fumigatus are different from those in yeast.
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21
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Yan J, Du T, Zhao W, Hartmann T, Lu H, Lü Y, Ouyang H, Jiang X, Sun L, Jin C. Transcriptome and biochemical analysis reveals that suppression of GPI-anchor synthesis leads to autophagy and possible necroptosis in Aspergillus fumigatus. PLoS One 2013; 8:e59013. [PMID: 23527074 PMCID: PMC3601126 DOI: 10.1371/journal.pone.0059013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 02/08/2013] [Indexed: 11/30/2022] Open
Abstract
Previously, it has been shown that GPI proteins are required for cell wall synthesis and organization in Aspergillus fumigatus, a human opportunistic pathogen causing life-threatening invasive aspergillosis (IA) in immunocompromised patients. Blocking GPI anchor synthesis leads to severe phenotypes such as cell wall defects, increased cell death, and attenuated virulence. However, the mechanism by which these phenotypes are induced is unclear. To gain insight into global effects of GPI anchoring in A. fumigatus, in this study a conditional expression mutant was constructed and a genome wide transcriptome analysis was carried out. Our results suggested that suppression of GPI anchor synthesis mainly led to activation of phosphatidylinositol (PtdIns) signaling and ER stress. Biochemical and morphological evidence showed that autophagy was induced in response to suppression of the GPI anchor synthesis, and also an increased necroptosis was observed. Based on our results, we propose that activation of PtdIns3K and increased cytosolic Ca2+, which was induced by both ER stress and PtdIns signaling, acted as the main effectors to induce autophagy and possible necroptosis.
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Affiliation(s)
- Jianghong Yan
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
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22
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Abstract
The composition and organization of the cell walls from Saccharomyces cerevisiae, Candida albicans, Aspergillus fumigatus, Schizosaccharomyces pombe, Neurospora crassa, and Cryptococcus neoformans are compared and contrasted. These cell walls contain chitin, chitosan, β-1,3-glucan, β-1,6-glucan, mixed β-1,3-/β-1,4-glucan, α-1,3-glucan, melanin, and glycoproteins as major constituents. A comparison of these cell walls shows that there is a great deal of variability in fungal cell wall composition and organization. However, in all cases, the cell wall components are cross-linked together to generate a cell wall matrix. The biosynthesis and properties of each of the major cell wall components are discussed. The chitin and glucans are synthesized and extruded into the cell wall space by plasma membrane-associated chitin synthases and glucan synthases. The glycoproteins are synthesized by ER-associated ribosomes and pass through the canonical secretory pathway. Over half of the major cell wall proteins are modified by the addition of a glycosylphosphatidylinositol anchor. The cell wall glycoproteins are also modified by the addition of O-linked oligosaccharides, and their N-linked oligosaccharides are extensively modified during their passage through the secretory pathway. These cell wall glycoprotein posttranslational modifications are essential for cross-linking the proteins into the cell wall matrix. Cross-linking the cell wall components together is essential for cell wall integrity. The activities of four groups of cross-linking enzymes are discussed. Cell wall proteins function as cross-linking enzymes, structural elements, adhesins, and environmental stress sensors and protect the cell from environmental changes.
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Affiliation(s)
- Stephen J Free
- Department of Biological Sciences, SUNY, University at Buffalo, Buffalo, New York, USA.
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Suh MJ, Fedorova ND, Cagas SE, Hastings S, Fleischmann RD, Peterson SN, Perlin DS, Nierman WC, Pieper R, Momany M. Development stage-specific proteomic profiling uncovers small, lineage specific proteins most abundant in the Aspergillus Fumigatus conidial proteome. Proteome Sci 2012; 10:30. [PMID: 22545825 PMCID: PMC3424117 DOI: 10.1186/1477-5956-10-30] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 04/30/2012] [Indexed: 11/14/2022] Open
Abstract
Background The pathogenic mold Aspergillus fumigatus is the most frequent infectious cause of death in severely immunocompromised individuals such as leukemia and bone marrow transplant patients. Germination of inhaled conidia (asexual spores) in the host is critical for the initiation of infection, but little is known about the underlying mechanisms of this process. Results To gain insights into early germination events and facilitate the identification of potential stage-specific biomarkers and vaccine candidates, we have used quantitative shotgun proteomics to elucidate patterns of protein abundance changes during early fungal development. Four different stages were examined: dormant conidia, isotropically expanding conidia, hyphae in which germ tube emergence has just begun, and pre-septation hyphae. To enrich for glycan-linked cell wall proteins we used an alkaline cell extraction method. Shotgun proteomic resulted in the identification of 375 unique gene products with high confidence, with no evidence for enrichment of cell wall-immobilized and secreted proteins. The most interesting discovery was the identification of 52 proteins enriched in dormant conidia including 28 proteins that have never been detected in the A. fumigatus conidial proteome such as signaling protein Pil1, chaperones BipA and calnexin, and transcription factor HapB. Additionally we found many small, Aspergillus specific proteins of unknown function including 17 hypothetical proteins. Thus, the most abundant protein, Grg1 (AFUA_5G14210), was also one of the smallest proteins detected in this study (M.W. 7,367). Among previously characterized proteins were melanin pigment and pseurotin A biosynthesis enzymes, histones H3 and H4.1, and other proteins involved in conidiation and response to oxidative or hypoxic stress. In contrast, expanding conidia, hyphae with early germ tubes, and pre-septation hyphae samples were enriched for proteins responsible for housekeeping functions, particularly translation, respiratory metabolism, amino acid and carbohydrate biosynthesis, and the tricarboxylic acid cycle. Conclusions The observed temporal expression patterns suggest that the A. fumigatus conidia are dominated by small, lineage-specific proteins. Some of them may play key roles in host-pathogen interactions, signal transduction during conidial germination, or survival in hostile environments.
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Affiliation(s)
- Moo-Jin Suh
- The J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD, USA
| | - Natalie D Fedorova
- The J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD, USA
| | - Steven E Cagas
- University of Medicine and Dentistry of New Jersey, Newark, NJ, USA
| | - Susan Hastings
- Department of Plant Biology, University of Georgia, Athens, GA, USA
| | | | - Scott N Peterson
- The J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD, USA
| | - David S Perlin
- University of Medicine and Dentistry of New Jersey, Newark, NJ, USA
| | - William C Nierman
- The J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD, USA
| | - Rembert Pieper
- The J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD, USA
| | - Michelle Momany
- Department of Plant Biology, University of Georgia, Athens, GA, USA
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Protein Glycosylation in Aspergillus fumigatus Is Essential for Cell Wall Synthesis and Serves as a Promising Model of Multicellular Eukaryotic Development. Int J Microbiol 2011; 2012:654251. [PMID: 21977037 PMCID: PMC3184424 DOI: 10.1155/2012/654251] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 07/19/2011] [Indexed: 02/05/2023] Open
Abstract
Glycosylation is a conserved posttranslational modification that is found in all eukaryotes, which helps generate proteins with multiple functions. Our knowledge of glycosylation mainly comes from the investigation of the yeast Saccharomyces cerevisiae and mammalian cells. However, during the last decade, glycosylation in the human pathogenic mold Aspergillus fumigatus has drawn significant attention. It has been revealed that glycosylation in A. fumigatus is crucial for its growth, cell wall synthesis, and development and that the process is more complicated than that found in the budding yeast S. cerevisiae. The present paper implies that the investigation of glycosylation in A. fumigatus is not only vital for elucidating the mechanism of fungal cell wall synthesis, which will benefit the design of new antifungal therapies, but also helps to understand the role of protein glycosylation in the development of multicellular eukaryotes. This paper describes the advances in functional analysis of protein glycosylation in A. fumigatus.
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What makes Aspergillus fumigatus a successful pathogen? Genes and molecules involved in invasive aspergillosis. Rev Iberoam Micol 2010; 27:155-82. [PMID: 20974273 DOI: 10.1016/j.riam.2010.10.003] [Citation(s) in RCA: 267] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 10/06/2010] [Accepted: 10/07/2010] [Indexed: 11/21/2022] Open
Abstract
Aspergillus fumigatus is an opportunistic pathogen that causes 90% of invasive aspergillosis (IA) due to Aspergillus genus, with a 50-95% mortality rate. It has been postulated that certain virulence factors are characteristic of A. fumigatus, but the "non-classical" virulence factors seem to be highly variable. Overall, published studies have demonstrated that the virulence of this fungus is multifactorial, associated with its structure, its capacity for growth and adaptation to stress conditions, its mechanisms for evading the immune system and its ability to cause damage to the host. In this review we intend to give a general overview of the genes and molecules involved in the development of IA. The thermotolerance section focuses on five genes related with the capacity of the fungus to grow at temperatures above 30°C (thtA, cgrA, afpmt1, kre2/afmnt1, and hsp1/asp f 12). The following sections discuss molecules and genes related to interaction with the host and with the immune responses. These sections include β-glucan, α-glucan, chitin, galactomannan, galactomannoproteins (afmp1/asp f 17 and afmp2), hydrophobins (rodA/hyp1 and rodB), DHN-melanin, their respective synthases (fks1, rho1-4, ags1-3, chsA-G, och1-4, mnn9, van1, anp1, glfA, pksP/alb1, arp1, arp2, abr1, abr2, and ayg1), and modifying enzymes (gel1-7, bgt1, eng1, ecm33, afpigA, afpmt1-2, afpmt4, kre2/afmnt1, afmnt2-3, afcwh41 and pmi); several enzymes related to oxidative stress protection such as catalases (catA, cat1/catB, cat2/katG, catC, and catE), superoxide dismutases (sod1, sod2, sod3/asp f 6, and sod4), fatty acid oxygenases (ppoA-C), glutathione tranferases (gstA-E), and others (afyap1, skn7, and pes1); and efflux transporters (mdr1-4, atrF, abcA-E, and msfA-E). In addition, this review considers toxins and related genes, such as a diffusible toxic substance from conidia, gliotoxin (gliP and gliZ), mitogillin (res/mitF/asp f 1), hemolysin (aspHS), festuclavine and fumigaclavine A-C, fumitremorgin A-C, verruculogen, fumagillin, helvolic acid, aflatoxin B1 and G1, and laeA. Two sections cover genes and molecules related with nutrient uptake, signaling and metabolic regulations involved in virulence, including enzymes, such as serine proteases (alp/asp f 13, alp2, and asp f 18), metalloproteases (mep/asp f 5, mepB, and mep20), aspartic proteases (pep/asp f 10, pep2, and ctsD), dipeptidylpeptidases (dppIV and dppV), and phospholipases (plb1-3 and phospholipase C); siderophores and iron acquisition (sidA-G, sreA, ftrA, fetC, mirB-C, and amcA); zinc acquisition (zrfA-H, zafA, and pacC); amino acid biosynthesis, nitrogen uptake, and cross-pathways control (areA, rhbA, mcsA, lysF, cpcA/gcn4p, and cpcC/gcn2p); general biosynthetic pathway (pyrG, hcsA, and pabaA), trehalose biosynthesis (tpsA and tpsB), and other regulation pathways such as those of the MAP kinases (sakA/hogA, mpkA-C, ste7, pbs2, mkk2, steC/ste11, bck1, ssk2, and sho1), G-proteins (gpaA, sfaD, and cpgA), cAMP-PKA signaling (acyA, gpaB, pkaC1, and pkaR), His kinases (fos1 and tcsB), Ca(2+) signaling (calA/cnaA, crzA, gprC and gprD), and Ras family (rasA, rasB, and rhbA), and others (ace2, medA, and srbA). Finally, we also comment on the effect of A. fumigatus allergens (Asp f 1-Asp f 34) on IA. The data gathered generate a complex puzzle, the pieces representing virulence factors or the different activities of the fungus, and these need to be arranged to obtain a comprehensive vision of the virulence of A. fumigatus. The most recent gene expression studies using DNA-microarrays may be help us to understand this complex virulence, and to detect targets to develop rapid diagnostic methods and new antifungal agents.
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Walker CA, Gómez BL, Mora-Montes HM, Mackenzie KS, Munro CA, Brown AJP, Gow NAR, Kibbler CC, Odds FC. Melanin externalization in Candida albicans depends on cell wall chitin structures. EUKARYOTIC CELL 2010; 9:1329-42. [PMID: 20543065 PMCID: PMC2937336 DOI: 10.1128/ec.00051-10] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Accepted: 06/01/2010] [Indexed: 01/03/2023]
Abstract
The fungal pathogen Candida albicans produces dark-pigmented melanin after 3 to 4 days of incubation in medium containing l-3,4-dihydroxyphenylalanine (l-DOPA) as a substrate. Expression profiling of C. albicans revealed very few genes significantly up- or downregulated by growth in l-DOPA. We were unable to determine a possible role for melanin in the virulence of C. albicans. However, we showed that melanin was externalized from the fungal cells in the form of electron-dense melanosomes that were free or often loosely bound to the cell wall exterior. Melanin production was boosted by the addition of N-acetylglucosamine to the medium, indicating a possible association between melanin production and chitin synthesis. Melanin externalization was blocked in a mutant specifically disrupted in the chitin synthase-encoding gene CHS2. Melanosomes remained within the outermost cell wall layers in chs3Delta and chs2Delta chs3Delta mutants but were fully externalized in chs8Delta and chs2Delta chs8Delta mutants. All the CHS mutants synthesized dark pigment at equivalent rates from mixed membrane fractions in vitro, suggesting it was the form of chitin structure produced by the enzymes, not the enzymes themselves, that was involved in the melanin externalization process. Mutants with single and double disruptions of the chitinase genes CHT2 and CHT3 and the chitin pathway regulator ECM33 also showed impaired melanin externalization. We hypothesize that the chitin product of Chs3 forms a scaffold essential for normal externalization of melanosomes, while the Chs8 chitin product, probably produced in cell walls in greater quantity in the absence of CHS2, impedes externalization.
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Affiliation(s)
- Claire A. Walker
- Aberdeen Fungal Group, University of Aberdeen, Institute of Medical Sciences, Aberdeen AB25 2ZD, United Kingdom
| | - Beatriz L. Gómez
- Department of Medical Microbiology, Royal Free Hampstead NHS Trust, Pond Street, London NW3 2QG, United Kingdom
| | - Héctor M. Mora-Montes
- Aberdeen Fungal Group, University of Aberdeen, Institute of Medical Sciences, Aberdeen AB25 2ZD, United Kingdom
| | - Kevin S. Mackenzie
- Aberdeen Fungal Group, University of Aberdeen, Institute of Medical Sciences, Aberdeen AB25 2ZD, United Kingdom
| | - Carol A. Munro
- Aberdeen Fungal Group, University of Aberdeen, Institute of Medical Sciences, Aberdeen AB25 2ZD, United Kingdom
| | - Alistair J. P. Brown
- Aberdeen Fungal Group, University of Aberdeen, Institute of Medical Sciences, Aberdeen AB25 2ZD, United Kingdom
| | - Neil A. R. Gow
- Aberdeen Fungal Group, University of Aberdeen, Institute of Medical Sciences, Aberdeen AB25 2ZD, United Kingdom
| | - Christopher C. Kibbler
- Department of Medical Microbiology, Royal Free Hampstead NHS Trust, Pond Street, London NW3 2QG, United Kingdom
| | - Frank C. Odds
- Aberdeen Fungal Group, University of Aberdeen, Institute of Medical Sciences, Aberdeen AB25 2ZD, United Kingdom
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Role of Aspergillus fumigatus DvrA in host cell interactions and virulence. EUKARYOTIC CELL 2010; 9:1432-40. [PMID: 20675576 DOI: 10.1128/ec.00055-10] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The transcription factors that regulate Aspergillus fumigatus interactions with host cells and virulence are incompletely defined. We investigated the role of the putative C2H2 transcription factor DvrA in governing these processes. Although DvrA was identified by its limited homology to Candida albicans Bcr1, a ΔdvrA mutant strain of A. fumigatus had wild-type adherence to host constituents in vitro. However, it had increased capacity to damage both endothelial cells and a pulmonary epithelial cell line compared to the ability of the wild-type strain and a ΔdvrA::dvrA-complemented strain. This increase in damage required direct contact between the mutant and host cells. The ΔdvrA mutant also stimulated greater CCL20, interleukin-8, and tumor necrosis factor mRNA expression in a pulmonary epithelial cell line compared to levels induced by the control strains. Also, it was resistant to nikkomycin Z, suggesting an altered cell wall composition. As predicted by these in vitro results, the ΔdvrA mutant had increased virulence and stimulated a greater pulmonary inflammatory response than the wild-type strain and ΔdvrA::dvrA-complemented strains in the nonneutropenic mouse model of invasive pulmonary aspergillosis. These results indicate that DvrA influences A. fumigatus virulence as well as its capacity to damage host cells and stimulate a proinflammatory response.
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The Aspergillus fumigatus cspA gene encoding a repeat-rich cell wall protein is important for normal conidial cell wall architecture and interaction with host cells. EUKARYOTIC CELL 2010; 9:1403-15. [PMID: 20656913 DOI: 10.1128/ec.00126-10] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
cspA (for cell surface protein A) encodes a repeat-rich glycophosphatidylinositol (GPI)-anchored cell wall protein (CWP) in the pathogenic fungus Aspergillus fumigatus. The number of repeats in cspA varies among isolates, and this trait is used for typing closely related strains of A. fumigatus. We have previously shown that deletion of cspA is associated with rapid conidial germination and reduced adhesion of dormant conidia. Here we show that cspA can be extracted with hydrofluoric acid (HF) from the cell wall, suggesting that it is a GPI-anchored CWP. The cspA-encoded CWP is unmasked during conidial germination and is surface expressed during hyphal growth. Deletion of cspA results in weakening of the conidial cell wall, whereas its overexpression increases conidial resistance to cell wall-degrading enzymes and inhibits conidial germination. Double mutant analysis indicates that cspA functionally interacts with the cell wall protein-encoding genes ECM33 and GEL2. Deletion of cspA together with ECM33 or GEL2 results in strongly reduced conidial adhesion, increased disorganization of the conidial cell wall, and exposure of the underlying layers of chitin and beta-glucan. This is correlated with increasing susceptibility of the DeltacspA, DeltaECM33, and DeltacspA DeltaECM33 mutants to conidial phagocytosis and killing by human macrophages and hyphal damage induced by neutrophils. However, these strains did not exhibit altered virulence in mice with infected lungs. Collectively, these results suggest a role for cspA in maintaining the strength and integrity of the cell wall.
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Fang W, Yu X, Wang B, Zhou H, Ouyang H, Ming J, Jin C. Characterization of the Aspergillus fumigatus phosphomannose isomerase Pmi1 and its impact on cell wall synthesis and morphogenesis. Microbiology (Reading) 2009; 155:3281-3293. [DOI: 10.1099/mic.0.029975-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Phosphomannose isomerase (PMI) is an enzyme catalysing the interconversion of mannose 6-phosphate (Man-6-P) and fructose 6-phosphate (Fru-6-P). The reaction catalysed by PMI is the first committed step in the synthesis of mannose-containing sugar chains and provides a link between glucose metabolism and mannosylation. In this study, the pmi1 gene was identified to encode PMI in the human fungal pathogen Aspergillus fumigatus. Characterization of A. fumigatus Pmi1 expressed in Escherichia coli revealed that this PMI mainly catalysed the conversion of Fru-6-P to Man-6-P and that its binding affinity for Man-6-P was similar to that of yeast PMIs, but different to those of PMIs from bacteria or animals. Loss of pmi1 was lethal unless Man was provided in the growth medium. However, a Δpmi1 mutant cell showed a significantly reduced growth rate at a high concentration of Man. Biochemical analysis revealed that both inadequate and replete Man led to an accumulation of intracellular Man-6-P and a reduction in the amount of α-glucan in the cell wall. Uncoupling of the link between energy production and glycosylation by deletion of the pmi1 gene led to phenotypes such as defects in cell wall integrity, abnormal morphology and reduced conidiation. Our results reveal that PMI activity is essential for viability and plays a central regulatory role in both cell wall synthesis and energy production in A. fumigatus.
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Affiliation(s)
- Wenxia Fang
- Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Xiaoying Yu
- Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Bin Wang
- Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Hui Zhou
- Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Haomiao Ouyang
- Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Jia Ming
- Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Cheng Jin
- Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
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Gastebois A, Clavaud C, Aimanianda V, Latgé JP. Aspergillus fumigatus: cell wall polysaccharides, their biosynthesis and organization. Future Microbiol 2009; 4:583-95. [DOI: 10.2217/fmb.09.29] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aspergillus fumigatus is the most prevalent thermophilic inhabitants of decaying vegetation and one of the most important human opportunistic fungal pathogens. Like other fungi, A. fumigatus cells are covered by a cell wall, which is both a protective, rigid exoskeleton and a dynamic structure, undergoing constant modification depending on its environment. The cell wall, in the majority of fungi, is composed of polysaccharides, and understanding the biochemical organization and biogenesis of an A. fumigatus cell wall is essential as this envelop is continuously in contact with the environment/host cell and acts as a sieve and reservoir for molecules, such as enzymes and toxins that play an active role during infection. This article is intended to give an overview of the biosynthesis of constituent cell wall polysaccharides and their postsynthetic modification in A. fumigatus, it also discusses the antifungal drugs that affect cell wall polysaccharide biosynthesis.
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Affiliation(s)
- Amandine Gastebois
- Unite des Aspergillus, Institut Pasteur, 25–28 rue du Docteur Roux, 75724, Paris, cedex 15, France
| | - Cécile Clavaud
- Unite des Aspergillus, Institut Pasteur, 25–28 rue du Docteur Roux, 75724, Paris, cedex 15, France
| | - Vishukumar Aimanianda
- Unite des Aspergillus, Institut Pasteur, 25–28 rue du Docteur Roux, 75724, Paris, cedex 15, France
| | - Jean-Paul Latgé
- Unite des Aspergillus, Institut Pasteur, 25–28 rue du Docteur Roux, 75724, Paris, cedex 15, France
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Zhang L, Feng D, Fang W, Ouyang H, Luo Y, Du T, Jin C. Comparative proteomic analysis of an Aspergillus fumigatus mutant deficient in glucosidase I (AfCwh41). MICROBIOLOGY-SGM 2009; 155:2157-2167. [PMID: 19389762 DOI: 10.1099/mic.0.027490-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Alpha-glucosidase I regulates trimming of the terminal alpha-1,2-glucose residue in the N-glycan processing pathway, which plays an important role in quality control systems in mammalian cells. Previously, we identified the gene encoding alpha-glucosidase I in the opportunistic human fungal pathogen Aspergillus fumigatus, namely Afcwh41. Deletion of the Afcwh41 gene results in a severe reduction of conidia formation, a temperature-sensitive deficiency of cell wall integrity, and abnormalities of polar growth and septation. An upregulation of the genes encoding Rho-type GTPases was also observed, which suggests activation of the cell wall integrity pathway in the mutant. Using 2D gel analysis, we revealed that the proteins involved in protein assembly, ubiquitin-mediated degradation and actin organization are altered in the DeltaAfcwh41 mutant. Evidence was obtained for a defect in the polarized localization of the actin cytoskeleton in the mutant. Our results suggest that blocking of the glucose trimming in A. fumigatus might induce accumulation of misfolded proteins in the endoplasmic reticulum; these misfolded proteins are probably required for cell wall synthesis and thus activate the cell wall integrity pathway, which then causes the abnormal polarity associated with the DeltaAfcwh41 mutant.
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Affiliation(s)
- Lei Zhang
- Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Deqin Feng
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Wenxia Fang
- Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Haomiao Ouyang
- Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yuanming Luo
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Ting Du
- Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Cheng Jin
- Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
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Identification of genes that are preferentially expressed in conidiogenous cell development of Metarhizium anisopliae by suppression subtractive hybridization. Curr Genet 2009; 55:263-71. [PMID: 19352680 DOI: 10.1007/s00294-009-0242-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Revised: 03/20/2009] [Accepted: 03/23/2009] [Indexed: 01/11/2023]
Abstract
The insect pathogenic fungus Metarhizium anisopliae is widely used as an insect biocontrol agent. The M. anisopliae conidium plays an important role in pathogenesis and disease transmission. The aim of this study was to identify genes whose expression is up-regulated during conidiogenous cell development. This is a powerful strategy for obtaining insight into the molecular events that regulate conidiation. We isolated genes that are preferentially expressed in the developing conidiophores of the common fungal locust pathogen M. anisopliae CQMa102 using suppression subtractive hybridization. Based on the results of cDNA array dot blotting, we identified 109 unique expressed sequence tags (ESTs) that were up-regulated more than fivefold during conidiophore formation. Among these 109 ESTs were 45 (41.3%) with significant similarity to NCBI annotated hypothetical proteins, 35 (32.1%) with low similarity to known or predicted genes that might represent novel genes, and 29 (26.6%) with significant similarity to known proteins involved in various cell and molecular processes, such as ell structure and function, cell metabolism, protein metabolism, stress response, nucleic acid metabolism, and cell cycle and growth. We confirmed the up-regulation of 11 randomly selected genes with real-time reverse transcriptase-PCR analysis. The results of this study provide a preliminary description of genes that may be involved in the molecular regulation of fungal conidiogenesis.
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Ejzykowicz DE, Cunha MM, Rozental S, Solis NV, Gravelat FN, Sheppard DC, Filler SG. The Aspergillus fumigatus transcription factor Ace2 governs pigment production, conidiation and virulence. Mol Microbiol 2009; 72:155-69. [PMID: 19220748 PMCID: PMC2690528 DOI: 10.1111/j.1365-2958.2009.06631.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Aspergillus fumigatus causes serious and frequently fatal infections in immunocompromised patients. To investigate the regulation of virulence of this fungus, we constructed and analysed an A. fumigatus mutant that lacked the transcription factor Ace2, which influences virulence in other fungi. The Deltaace2 mutant had dysmorphic conidiophores, reduced conidia production and abnormal conidial cell wall architecture. This mutant produced an orange pigment when grown on solid media, although its conidia had normal pigmentation. Conidia of the Deltaace2 mutant were larger and had accelerated germination. The resulting germlings were resistant to hydrogen peroxide, but not other stressors. Non-neutropenic mice that were immunosuppressed with cortisone acetate and infected with the Deltaace2 mutant had accelerated mortality, greater pulmonary fungal burden, and increased pulmonary inflammatory responses compared with mice infected with the wild-type or Deltaace2::ace2-complemented strains. The Deltaace2 mutant had reduced ppoC, ecm33 and ags3 mRNA expression. It is known that A. fumigatus mutants with absent or reduced expression of these genes have increased virulence in mice, as well as other phenotypic similarities to the Deltaace2 mutant. Therefore, reduced expression of these genes likely contributes to the increased virulence of the Deltaace2 mutant.
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Affiliation(s)
- Daniele E Ejzykowicz
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
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Cao W, Maruyama JI, Kitamoto K, Sumikoshi K, Terada T, Nakamura S, Shimizu K. Using a new GPI-anchored-protein identification system to mine the protein databases of Aspergillus fumigatus, Aspergillus nidulans, and Aspergillus oryzae. J GEN APPL MICROBIOL 2009; 55:381-93. [DOI: 10.2323/jgam.55.381] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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The cell wall of the human pathogen Candida glabrata: differential incorporation of novel adhesin-like wall proteins. EUKARYOTIC CELL 2008; 7:1951-64. [PMID: 18806209 DOI: 10.1128/ec.00284-08] [Citation(s) in RCA: 178] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The cell wall of the human pathogen Candida glabrata governs initial host-pathogen interactions that underlie the establishment of fungal infections. With the aim of identifying species-specific features that may directly relate to its virulence, we have investigated the cell wall of C. glabrata using a multidisciplinary approach that combines microscopy imaging, biochemical studies, bioinformatics, and tandem mass spectrometry. Electron microscopy revealed a bilayered wall structure in which the outer layer is packed with mannoproteins. Biochemical studies showed that C. glabrata walls incorporate 50% more protein than Saccharomyces cerevisiae walls and, consistent with this, have a higher mannose/glucose ratio. Evidence is presented that C. glabrata walls contain glycosylphosphatidylinositol (GPI) proteins, covalently bound to the wall 1,6-beta-glucan, as well as proteins linked through a mild-alkali-sensitive linkage to 1,3-beta-glucan. A comprehensive genome-wide in silico inspection showed that in comparison to other fungi, C. glabrata contains an exceptionally large number, 67, of genes encoding adhesin-like GPI proteins. Phylogenetically these adhesin-like proteins form different clusters, one of which is the lectin-like EPA family. Mass spectrometric analysis identified 23 cell wall proteins, including 4 novel adhesin-like proteins, Awp1/2/3/4, and Epa6, which is involved in adherence to human epithelia and biofilm formation. Importantly, the presence of adhesin-like proteins in the wall depended on the growth stage and on the genetic background used, and this was reflected in alterations in adhesion capacity and cell surface hydrophobicity. We propose that the large repertoire of adhesin(-like) genes of C. glabrata contributes to its adaptability and virulence.
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Jiang H, Ouyang H, Zhou H, Jin C. GDP-mannose pyrophosphorylase is essential for cell wall integrity, morphogenesis and viability of Aspergillus fumigatus. Microbiology (Reading) 2008; 154:2730-2739. [DOI: 10.1099/mic.0.2008/019240-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Hechun Jiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Haomiao Ouyang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Hui Zhou
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Cheng Jin
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
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Leng W, Liu T, Li R, Yang J, Wei C, Zhang W, Jin Q. Proteomic profile of dormant Trichophyton rubrum conidia. BMC Genomics 2008; 9:303. [PMID: 18578874 PMCID: PMC2443143 DOI: 10.1186/1471-2164-9-303] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Accepted: 06/25/2008] [Indexed: 11/18/2022] Open
Abstract
Background Trichophyton rubrum is the most common dermatophyte causing fungal skin infections in humans. Asexual sporulation is an important means of propagation for T. rubrum, and conidia produced by this way are thought to be the primary cause of human infections. Despite their importance in pathogenesis, the conidia of T. rubrum remain understudied. We intend to intensively investigate the proteome of dormant T. rubrum conidia to characterize its molecular and cellular features and to enhance the development of novel therapeutic strategies. Results The proteome of T. rubrum conidia was analyzed by combining shotgun proteomics with sample prefractionation and multiple enzyme digestion. In total, 1026 proteins were identified. All identified proteins were compared to those in the NCBI non-redundant protein database, the eukaryotic orthologous groups database, and the gene ontology database to obtain functional annotation information. Functional classification revealed that the identified proteins covered nearly all major biological processes. Some proteins were spore specific and related to the survival and dispersal of T. rubrum conidia, and many proteins were important to conidial germination and response to environmental conditions. Conclusion Our results suggest that the proteome of T. rubrum conidia is considerably complex, and that the maintenance of conidial dormancy is an intricate and elaborate process. This data set provides the first global framework for the dormant T. rubrum conidia proteome and is a stepping stone on the way to further study of the molecular mechanisms of T. rubrum conidial germination and the maintenance of conidial dormancy.
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Affiliation(s)
- Wenchuan Leng
- State Key Laboratory for Molecular Virology and Genetic Engineering, Institute of Pathogen Biology, Chinese Academy of Medical Sciences, Beijing 100730, PR China.
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Down-regulation of Sclerotinia sclerotiorum gene expression in response to infection with Sclerotinia sclerotiorum debilitation-associated RNA virus. Virus Res 2008; 135:95-106. [PMID: 18384901 DOI: 10.1016/j.virusres.2008.02.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2007] [Revised: 02/23/2008] [Accepted: 02/23/2008] [Indexed: 12/24/2022]
Abstract
We have previously presented convincing evidence in support of a viral etiology for the debilitation phenotype exhibited by strain Ep-1PN of Sclerotinia sclerotiorum. To explore the possible mechanisms underlying fungal pathogenicity and hyphal growth, potential genes whose expression was down-regulated in Ep-1PN were identified from a cDNA library of the virus-free strain Ep-1PNAa, which is a single ascospore derivative of strain Ep-1PN, using reverse northern blot analysis. A total of 1116 cDNA clones were targeted and, following PCR re-amplification, 210 cDNA clones were selected as candidates, of which 16 cDNA clones were subjected to northern blot analysis for further confirmation. The results showed that 12 clones represented genes that were differentially expressed in the virus-free strain compared to the virus-infected one. Of the 210 clones that were sequenced, 150 had non-redundant sequences and of these 92% (138 clones) had significant homology to fungal genes in the databases examined. The remaining 12 clones did not have any matches. The differentially expressed genes represented a broad spectrum of biological functions including carbon and energy metabolism, protein synthesis and transport, signal transduction and stress response. This study provides the first insight into genes differentially expressed between the virus-free strain Ep-1PNAa and the virus-infected strain Ep-1PN. The possible relationships between mycovirus-mediated changes in cellular gene expression and observed phenotypes are discussed.
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Sagaram US, Shaw BD, Shim WB. Fusarium verticillioides GAP1, a gene encoding a putative glycolipid-anchored surface protein, participates in conidiation and cell wall structure but not virulence. MICROBIOLOGY-SGM 2007; 153:2850-2861. [PMID: 17768230 DOI: 10.1099/mic.0.2007/007708-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Fusarium verticillioides is an important pathogen of maize that causes ear rot and produces the mycotoxins known as fumonisins. To date, knowledge of pathogenicity and the regulation of fumonisin biosynthesis in F. verticillioides is limited. Here, the molecular characterization of GAP1, a gene encoding a putative 540 aa protein that belongs to a glycolipid-anchored surface (GAS) protein family, is presented. F. verticillioides GAP1 was identified as an expressed sequence tag (EST) upregulated in a culture condition conducive to conidiation and fumonisin B(1) (FB(1)) production. GAP1 null mutants GAM126 (Deltagap1 : : HYG) and GAG8 (Deltagap1 : : GEN) exhibited restricted growth, with more aerial hyphae than their wild-type progenitor on solid media. No defect in mycelial mass or filamentous growth was observed when the GAM126 and GAG8 strains were grown in liquid media under shaking conditions. When grown in suspended conditions, GAM126 and GAG8 strains produced significantly fewer conidia and produced comparatively densely branched hyphae. Concanavalin A staining indicated that the GAP1 deletion altered the cell wall carbohydrate composition/deposition process. Deletion of GAP1 did not affect the production level of FB(1) or F. verticillioides virulence on maize seedlings and stalks. Complementation of GAM126 with the wild-type GAP1 gene restored growth, conidiation and cell wall abnormality phenotypes. The results suggest that GAP1 is associated with growth, development and conidiation in F. verticillioides, but not with pathogenicity or regulation of FB(1).
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Affiliation(s)
- Uma Shankar Sagaram
- Department of Plant Pathology and Microbiology, Program for the Biology of Filamentous Fungi, Texas A&M University, College Station, TX 77843-2132, USA
| | - Brian D Shaw
- Department of Plant Pathology and Microbiology, Program for the Biology of Filamentous Fungi, Texas A&M University, College Station, TX 77843-2132, USA
| | - Won-Bo Shim
- Department of Plant Pathology and Microbiology, Program for the Biology of Filamentous Fungi, Texas A&M University, College Station, TX 77843-2132, USA
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Hohl TM, Feldmesser M. Aspergillus fumigatus: principles of pathogenesis and host defense. EUKARYOTIC CELL 2007; 6:1953-63. [PMID: 17890370 PMCID: PMC2168400 DOI: 10.1128/ec.00274-07] [Citation(s) in RCA: 162] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Tobias M Hohl
- Infectious Disease Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, 1275 York Ave., New York, NY 10021, USA.
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Lamarre C, Ibrahim-Granet O, Du C, Calderone R, Latgé JP. Characterization of the SKN7 ortholog of Aspergillus fumigatus. Fungal Genet Biol 2007; 44:682-90. [PMID: 17337219 DOI: 10.1016/j.fgb.2007.01.009] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2006] [Revised: 01/18/2007] [Accepted: 01/22/2007] [Indexed: 11/16/2022]
Abstract
Reactive oxidant intermediates play a major role in the killing of Aspergillus fumigatus by phagocytes. In yeasts, SKN7 is a transcription factor contributing to the oxidative stress response. We investigated here the role of afSkn7p in the adaptation of A. fumigatus against oxidative stress. To analyze functionally the afSKN7 in A. fumigatus, we modified a quick PCR fusion methodology for targeted deletion in A. fumigatus. The afskn7Delta mutant was morphologically similar to the wild-type strain, but showed a growth inhibition phenotype associated with hydrogen peroxide and tert-butyl hydroperoxide. However, no significant virulence differences were observed between wild type, mutant and reconstituted strains in a murine model of pulmonary aspergillosis. This result indicated that an increased sensitivity of A. fumigatus to peroxides in vitro is not correlated with a modification of fungal virulence.
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Affiliation(s)
- Claude Lamarre
- Unité des Aspergillus, Institut Pasteur, 25 rue du Docteur Roux, 75724 Cedex 15, France.
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Li H, Zhou H, Luo Y, Ouyang H, Hu H, Jin C. Glycosylphosphatidylinositol (GPI) anchor is required in Aspergillus fumigatus for morphogenesis and virulence. Mol Microbiol 2007; 64:1014-27. [PMID: 17501924 DOI: 10.1111/j.1365-2958.2007.05709.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
In yeast, glycosylphosphatidylinositol (GPI) is essential for viability and plays an important role in biosynthesis and organization of cell wall. Initiation of the GPI anchor biosynthesis is catalysed by the GPI-N-acetylglucosaminyltransferase complex (GPI-GnT). The GPI3 (SPT14) gene is thought to encode the catalytic subunit of GPI-GnT complex. In contrast to Saccharomyces cerevisiae, little is known about the GPI biosynthesis in filamentous fungi. In this study, the afpig-a gene was identified as the homologue of the GPI3/pig-A gene in Aspergillus fumigatus, an opportunistic fungal pathogen. By replacement of the afpig-a gene with a pyrG gene, we obtained the null mutants. Although the Deltaafpig-a mutant exhibited a significant increased cell lysis instead of temperature-sensitive or conditional lethal phenotype associated to the GPI3 mutant of yeast, they could survive at temperatures from 30 degrees C to 50 degrees C. The analysis of the mutants showed that a completely blocking of the GPI anchor synthesis in A. fumigatus led to cell wall defect, abnormal hyphal growth, rapid conidial germination and aberrant conidiation. In vivo assays revealed that the mutant exhibited a reduced virulence in immunocompromised mice. The GPI anchor was not essential for viability, but required for the cell wall integrity, morphogenesis and virulence in A. fumigatus.
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Affiliation(s)
- Hong Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, and The General Hospital of Chinese People's Armed Police Forces, Beijing 100080, China
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