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Hu G, Qu X, Bhalla K, Xue P, Bakkeren E, Lee CWJ, Kronstad JW. Loss of the putative Rab GTPase, Ypt7, impairs the virulence of Cryptococcus neoformans. Front Microbiol 2024; 15:1437579. [PMID: 39119141 PMCID: PMC11306161 DOI: 10.3389/fmicb.2024.1437579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Accepted: 07/16/2024] [Indexed: 08/10/2024] Open
Abstract
Small GTPases of the Rab family coordinate multiple membrane fusion and trafficking events in eukaryotes. In fungi, the Rab GTPase, Ypt7, plays a critical role in late endosomal trafficking, and is required for homotypic fusion events in vacuole biogenesis and inheritance. In this study, we identified a putative YPT7 homologue in Cryptococcus neoformans, a fungal pathogen causing life threatening meningoencephalitis in immunocompromised individuals. As part of an ongoing effort to understand mechanisms of iron acquisition in C. neoformans, we established a role for Ypt7 in growth on heme as the sole iron source. Deletion of YPT7 also caused abnormal vacuolar morphology, defective endocytic trafficking and autophagy, and mislocalization of Aph1, a secreted vacuolar acid phosphatase. Ypt7 localized to the vacuolar membrane and membrane contact sites between the vacuole and mitochondria (vCLAMPs), and loss of the protein impaired growth on inhibitors of the electron transport chain. Additionally, Ypt7 was required for robust growth at 39°C, a phenotype likely involving the calcineurin signaling pathway because ypt7 mutants displayed increased susceptibility to the calcineurin-specific inhibitors, FK506 and cyclosporin A; the mutants also had impaired growth in either limiting or high levels of calcium. Finally, Ypt7 was required for survival during interactions with macrophages, and ypt7 mutants were attenuated for virulence in a mouse inhalation model thus demonstrating the importance of membrane trafficking functions in cryptococcosis.
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Affiliation(s)
- Guanggan Hu
- The Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Xianya Qu
- The Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Kabir Bhalla
- The Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Peng Xue
- The Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Erik Bakkeren
- The Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Christopher W. J. Lee
- The Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - James W. Kronstad
- The Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
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Infection and Immunity. Clin Immunol 2023. [DOI: 10.1016/b978-0-12-818006-8.00007-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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3
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Vilela DJM, Pinto RT, Cardoso TB, Paiva LV, Carneiro MAC, Carvalho GR, dos Santos JV. Purple acid phosphatases in coffee-genome-wide identification and the transcriptional profile of selected members in roots upon Pi starvation. 3 Biotech 2022; 12:335. [PMID: 36330378 PMCID: PMC9622964 DOI: 10.1007/s13205-022-03399-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 10/12/2022] [Indexed: 12/07/2022] Open
Abstract
Phosphorus (P) availability is determinant for crop productivity and, despite the sufficient amount of this nutrient in arable land, most of it remains insoluble, leading to the need of high fertilizer input. To cope with P scarcity forecasts and also for cropping costs alleviation, genotypes better adapted to promote P solubilization and absorption are required, especially for perennial crops. Coffee is one of these important perennial crops cultivated in soils with low P availability, and thus we aimed to study adaptive strategies to coffee genotypes in acquire phosphorus. In this study, we focused on rhizosphere phosphatase activity, a major characteristic related to P solubilization from organic pools. To explore the genetic basis of this characteristic, we firstly identified 29 Purple Acid Phosphatases (PAP) genes in C. canephora genome and selected five candidates with higher potential to encode secreted PAPs. We found that C. arabica genotypes have diverse profiles of rhizosphere phosphatase activity, as well as microbial biomass carbon, which we measured to explore the impact of the plant on microbiota and also to discriminate the phosphatase activity origin (plant or microorganism-derived). We selected two C. arabica cultivars with contrasting phosphatase activity and found that one PAP gene has a correlated gene expression profile with this characteristic. This work explores coffee adaptative responses to P starvation conditions, and the information provided can further contribute to breeding programs aiming better adapted genotypes for sustainable agriculture in face of current challenges. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-022-03399-6.
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Affiliation(s)
| | - Renan Terassi Pinto
- Laboratory of Molecular Biology, Department of Chemistry, Federal University of Lavras, Lavras, MG Brazil
| | | | - Luciano Vilela Paiva
- Laboratory of Molecular Biology, Department of Chemistry, Federal University of Lavras, Lavras, MG Brazil
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A Fragile Balance: Does Neutrophil Extracellular Trap Formation Drive Pulmonary Disease Progression? Cells 2021; 10:cells10081932. [PMID: 34440701 PMCID: PMC8394734 DOI: 10.3390/cells10081932] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/22/2021] [Accepted: 07/28/2021] [Indexed: 12/13/2022] Open
Abstract
Neutrophils act as the first line of defense during infection and inflammation. Once activated, they are able to fulfil numerous tasks to fight inflammatory insults while keeping a balanced immune response. Besides well-known functions, such as phagocytosis and degranulation, neutrophils are also able to release "neutrophil extracellular traps" (NETs). In response to most stimuli, the neutrophils release decondensed chromatin in a NADPH oxidase-dependent manner decorated with histones and granule proteins, such as neutrophil elastase, myeloperoxidase, and cathelicidins. Although primarily supposed to prevent microbial dissemination and fight infections, there is increasing evidence that an overwhelming NET response correlates with poor outcome in many diseases. Lung-related diseases especially, such as bacterial pneumonia, cystic fibrosis, chronic obstructive pulmonary disease, aspergillosis, influenza, and COVID-19, are often affected by massive NET formation. Highly vascularized areas as in the lung are susceptible to immunothrombotic events promoted by chromatin fibers. Keeping this fragile equilibrium seems to be the key for an appropriate immune response. Therapies targeting dysregulated NET formation might positively influence many disease progressions. This review highlights recent findings on the pathophysiological influence of NET formation in different bacterial, viral, and non-infectious lung diseases and summarizes medical treatment strategies.
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Han C, Yu Z, Zhang Y, Wang Z, Zhao J, Huang SX, Ma Z, Wen Z, Liu C, Xiang W. Discovery of Frenolicin B as Potential Agrochemical Fungicide for Controlling Fusarium Head Blight on Wheat. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:2108-2117. [PMID: 33586974 DOI: 10.1021/acs.jafc.0c04277] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In this study, the supernatant extract from fermentation broth of Streptomyces sp. NEAU-H3 showed strong antifungal activity against Fusarium graminearum strain PH-1 in vitro and in vivo. Three known pyranonaphthoquinones were isolated by means of an activity-guided method, and frenolicin B was characterized as the main active ingredient. Frenolicin B displayed strong antifungal activity against F. graminearum strain PH-1 with an EC50 value of 0.51 mg/L, which is lower than that of carbendazim (0.78 mg/L) but higher than that of phenamacril (0.18 mg/L). Frenolicin B could also strongly inhibit the mycelial growth of Fusarium species, including F. graminearum and F. asiaticum, as well as carbendazim-resistant Fusarium strains isolated from field, with EC50 values of 0.25-0.92 mg/L. Results from field experiments showed that the efficacy of frenolicin B in controlling Fusarium head blight at a treatment concentration of 75 g ai/ha was better than those of phenamacril (375 g ai/ha) and carbendazim (600 g ai/ha) or had no significant difference with that of phenamacril (375 g ai/ha) in 2 years. Scanning electron microscope and transmission electron microscope observations revealed that after treating F. graminearum mycelia with frenolicin B, the mycelia appeared aberrant and had an uneven thickness and swelling, the cytoplasm had disintegrated, and some cell contents were lost. Transcriptome analysis suggests that frenolicin B might inhibit the metabolism of nucleotides and energy by affecting genes involved in phosphorus utilization but did not affect the expression of myosin 5, which is the specific target of phenamacril. These findings indicate that frenolicin B may be a potential agrochemical fungicide for controlling Fusarium head blight.
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Affiliation(s)
- Chuanyu Han
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, People's Republic of China
| | - Zhiyin Yu
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, People's Republic of China
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, People's Republic of China
| | - Yuting Zhang
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, People's Republic of China
| | - Zhiyan Wang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, People's Republic of China
| | - Junwei Zhao
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, People's Republic of China
| | - Sheng-Xiong Huang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, People's Republic of China
| | - Zhonghua Ma
- State Key Laboratory of Rice Biology, and Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Ziyue Wen
- State Key Laboratory of Rice Biology, and Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Chongxi Liu
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, People's Republic of China
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, People's Republic of China
| | - Wensheng Xiang
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, People's Republic of China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, People's Republic of China
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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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Abstract
Aspergillus fumigatus is a saprotrophic fungus; its primary habitat is the soil. In its ecological niche, the fungus has learned how to adapt and proliferate in hostile environments. This capacity has helped the fungus to resist and survive against human host defenses and, further, to be responsible for one of the most devastating lung infections in terms of morbidity and mortality. In this review, we will provide (i) a description of the biological cycle of A. fumigatus; (ii) a historical perspective of the spectrum of aspergillus disease and the current epidemiological status of these infections; (iii) an analysis of the modes of immune response against Aspergillus in immunocompetent and immunocompromised patients; (iv) an understanding of the pathways responsible for fungal virulence and their host molecular targets, with a specific focus on the cell wall; (v) the current status of the diagnosis of different clinical syndromes; and (vi) an overview of the available antifungal armamentarium and the therapeutic strategies in the clinical context. In addition, the emergence of new concepts, such as nutritional immunity and the integration and rewiring of multiple fungal metabolic activities occurring during lung invasion, has helped us to redefine the opportunistic pathogenesis of A. fumigatus.
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Affiliation(s)
- Jean-Paul Latgé
- School of Medicine, University of Crete, Heraklion, Crete, Greece
| | - Georgios Chamilos
- School of Medicine, University of Crete, Heraklion, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Heraklion, Crete, Greece
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Sato T, Hachiya S, Inamura N, Ezawa T, Cheng W, Tawaraya K. Secretion of acid phosphatase from extraradical hyphae of the arbuscular mycorrhizal fungus Rhizophagus clarus is regulated in response to phosphate availability. MYCORRHIZA 2019; 29:599-605. [PMID: 31745622 DOI: 10.1007/s00572-019-00923-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 10/15/2019] [Indexed: 06/10/2023]
Abstract
Arbuscular mycorrhizal (AM) fungi increase phosphate (P) uptake by plants. Organic phosphate comprises 30-80% of total P in most agricultural soils. Some plants can utilize organic phosphate by secreting acid phosphatase (ACP) from their roots, especially under low P conditions. Although secretion of ACP from extraradical hyphae of AM fungi has been reported, the specific factors that affect the secretion of ACP are unknown. The objective of the present study was to investigate whether secretion of ACP from extraradical hyphae is induced by low P conditions. First, specimens of Allium fistulosum were either inoculated with the AM fungus Rhizophagus clarus strain CK001 or remained uninoculated and were grown in soil with 0.5 g P2O5 kg-1 soil or without P fertilization using two-compartment pots. Soil solution was collected using mullite ceramic tubes 45 days after sowing. The soil solution was analyzed for ACP activity by using p-nitrophenylphosphate. Second, Ri T-DNA transformed roots (i.e., hairy roots) of Linum usitatissimum inoculated with R. clarus were grown on solid minimal media with two P levels applied (3 and 30 μM P) using two-compartment Petri dishes under in vitro conditions. Hyphal exudates, extraradical hyphae, and hairy roots were collected and analyzed for ACP activity. ACP activity in the soil solution of the hyphal compartment in the A. fistulosum inoculation treatment was higher without P fertilization than with P fertilization. AM colonization also was higher without P fertilization than with P fertilization. In the in vitro two-compartment culture, ACP activity of hyphal exudates and extraradical hyphae were higher under the 3-μM treatment than under the 30-μM treatment. These findings suggest that the secretion of ACP from the extraradical hyphae of R. clarus into the hyphosphere is promoted under low P conditions.
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Affiliation(s)
- Takumi Sato
- Faculty of Agriculture, Yamagata University, Tsuruoka, 997-8555, Japan
| | - Shihomi Hachiya
- Faculty of Agriculture, Yamagata University, Tsuruoka, 997-8555, Japan
| | - Nozomi Inamura
- Faculty of Agriculture, Yamagata University, Tsuruoka, 997-8555, Japan
| | - Tatsuhiro Ezawa
- Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan
| | - Weiguo Cheng
- Faculty of Agriculture, Yamagata University, Tsuruoka, 997-8555, Japan
| | - Keitaro Tawaraya
- Faculty of Agriculture, Yamagata University, Tsuruoka, 997-8555, Japan.
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Abstract
Respiratory fungal infection is a severe clinical problem, especially in patients with compromised immune functions. Aspergillus, Cryptococcus, Pneumocystis, and endemic fungi are major pulmonary fungal pathogens that are able to result in life-threatening invasive diseases. Growing data being reported have indicated that multiple cells and molecules orchestrate the host's response to a fungal infection in the lung. Upon fungal challenge, innate myeloid cells including macrophages, dendritic cells (DC), and recruited neutrophils establish the first line of defense through the phagocytosis and secretion of cytokines. Natural killer cells control the fungal expansion in the lung via the direct and indirect killing of invading organisms. Adaptive immune cells including Th1 and Th17 cells confer anti-fungal activity by producing their signature cytokines, interferon-γ, and IL-17. In addition, lung epithelial cells (LEC) also participate in the resistance against fungal infection by internalization, inflammatory cytokine production, or antimicrobial peptide secretion. In the host cells mentioned above, various molecules with distinct functions modulate the immune defense signaling: Pattern recognition receptors (PRRs) such as dectin-1 expressed on the cell surface are involved in fungal recognition; adaptor proteins such as MyD88 and TRAF6 are required for transduction of signals to the nucleus for transcriptional regulation; inflammasomes also play crucial roles in the host's defense against a fungal infection in the lung. Furthermore, transcriptional factors modulate the transcriptions of a series of genes, especially those encoding cytokines and chemokines, which are predominant regulators in the infectious microenvironment, mediating the cellular and molecular immune responses against a fungal infection in the lung.
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Affiliation(s)
- Zhi Li
- The Joint Center for Infection and Immunity, Guangzhou Women and Children's Medical Center, Guangzhou Institute of Pediatrics, Guangzhou, China
- The Joint Center for Infection and Immunity, Institute Pasteur of Shanghai, Chinese Academy of Science, Shanghai, China
| | - Gen Lu
- The Joint Center for Infection and Immunity, Guangzhou Women and Children's Medical Center, Guangzhou Institute of Pediatrics, Guangzhou, China
| | - Guangxun Meng
- The Joint Center for Infection and Immunity, Institute Pasteur of Shanghai, Chinese Academy of Science, Shanghai, China
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10
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Hartung S, Rauh C, Hoang TNM, Jahreis S, Wagner K, Macheleidt J, Brakhage AA, Rummler S, Hochhaus A, von Lilienfeld-Toal M. Fast and Quantitative Evaluation of Human Leukocyte Interaction with Aspergillus fumigatus Conidia by Flow Cytometry. Cytometry A 2018; 95:332-338. [PMID: 30450827 DOI: 10.1002/cyto.a.23653] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 08/29/2018] [Accepted: 10/04/2018] [Indexed: 11/05/2022]
Abstract
Systemic infections with the opportunistic mold Aspergillus fumigatus are a great threat to immunocompromised patients such as transplant recipients. Immunological research on A. fumigatus involves the measurement of phagocytosis of fungal conidia (spores) by human phagocytes. Here, we present a fast and flexible way to analyze phagocytosis by flow cytometry using fluorescein isothiocyanate (FITC) labeling of conidia prior to co-incubation with human leukocytes and an anti-FITC counterstaining step postincubation to allow the discrimination of internalized and adherent conidia. In contrast to many other protocols, this method can be combined with further surface marker analyses. We sought to determine phagocytosis rates of A. fumigatus conidia in different stages and after several incubation times using this method. Moreover, we provide an example of application by comparing phagocytosis of A. fumigatus mutants to the wild type. © 2018 International Society for Advancement of Cytometry.
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Affiliation(s)
- Susann Hartung
- Hematology and Medical Oncology, Jena University Hospital, Jena, Germany.,Center for Sepsis Control and Care, Jena University Hospital, Jena, Germany.,Leibniz Institute for Infection Biology and Natural Product Research, Jena, Germany
| | - Christopher Rauh
- Hematology and Medical Oncology, Jena University Hospital, Jena, Germany
| | - Thi Ngoc Mai Hoang
- Leibniz Institute for Infection Biology and Natural Product Research, Jena, Germany.,Friedrich Schiller University, Jena, Germany
| | - Susanne Jahreis
- Hematology and Medical Oncology, Jena University Hospital, Jena, Germany.,Leibniz Institute for Infection Biology and Natural Product Research, Jena, Germany
| | - Kathleen Wagner
- Hematology and Medical Oncology, Jena University Hospital, Jena, Germany.,Center for Sepsis Control and Care, Jena University Hospital, Jena, Germany.,Leibniz Institute for Infection Biology and Natural Product Research, Jena, Germany
| | - Juliane Macheleidt
- Leibniz Institute for Infection Biology and Natural Product Research, Jena, Germany
| | - Axel A Brakhage
- Leibniz Institute for Infection Biology and Natural Product Research, Jena, Germany.,Friedrich Schiller University, Jena, Germany
| | - Silke Rummler
- Institute for Transfusion Medicine, Jena University Hospital, Jena, Germany
| | - Andreas Hochhaus
- Hematology and Medical Oncology, Jena University Hospital, Jena, Germany
| | - Marie von Lilienfeld-Toal
- Hematology and Medical Oncology, Jena University Hospital, Jena, Germany.,Center for Sepsis Control and Care, Jena University Hospital, Jena, Germany.,Leibniz Institute for Infection Biology and Natural Product Research, Jena, Germany
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11
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Gomes-Vieira AL, Paes-Vieira L, Zamboni DKBB, Dos-Santos ALA, Dick CF, Meyer-Fernandes JR. Ectophosphatase activity in the early-diverging fungus Blastocladiella emersonii: Biochemical characterization and possible role on cell differentiation. Fungal Genet Biol 2018; 117:43-53. [PMID: 30030178 DOI: 10.1016/j.fgb.2018.07.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 07/09/2018] [Accepted: 07/16/2018] [Indexed: 01/22/2023]
Abstract
Blastocladiella emersonii is an interesting model for studding the evolution of cell differentiation in eukaryotic cell because of its taxonomic position towards the base of the fungal phylogenetic tree and because it undergoes radical morphological and biochemical changes throughout its life cycle. In this work, we biochemically characterized a high alkaline phosphotyrosine phosphatase activity present on the cell surface (ectophosphatase) of B. emersonii. The ectophosphatase activity was strongly inhibited at acidic pH values as well as by specific phosphatase inhibitors, such as sodium orthovanadate and bpv-PHEN. In addition, the enzyme activity was modulated by the extracellular concentration of inorganic phosphate (Pi) present in both reaction mixture and culture medium. Phosphotyrosine was hydrolysed at the same extent of its analog, p-NPP, while the hydrolysis of phosphothreonine was 2-fold lower, suggesting that a phosphotyrosine ectophosphatase activity is present on the cell surface of B. emersonii. The ectophosphatase activity was also strongly inhibited by EGTA, indicating the participation of Ca2+ ions on catalysis. The hydrolysis of p-NPP was differentially regulated throughout the B. emersonii life cycle, suggesting that the ectophosphatase activity could be involved in cell differentiation processes. In support of this, the addition of bpv-PHEN or vanadate at the beginning of germination inhibited the differentiation of zoospores to germ cells, compared to control or tartrate-treated cells. On the other hand, if the inhibitors are added 15 or 30 min after initiation of germination the inhibitory effect on zoospore germination decreases significantly, suggesting that the phosphotyrosine ectophosphatase activity is important at the first minutes of germination. The addition of vanadate, molybdate and bpv-PHEN during vegetative growth inhibited the enlargement of the cells compared to control or tartrate-treated cells. Finally, vanadate or bpv-PHEN added during sporulation strongly inhibited zoospore biogenesis, indicating an important role of such ectophosphatases in this differentiation process. Taken together, these data show the existence of a high alkaline ectophosphotyrosine phosphatase activity in B. emersonii that is probably tied to cell differentiation processes of the fungus.
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Affiliation(s)
- André L Gomes-Vieira
- Instituto de Química, Departamento de Bioquímica, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brazil.
| | - Lisvane Paes-Vieira
- Laboratório de Bioquímica Celular, Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | - Dayana K B B Zamboni
- Instituto de Química, Departamento de Bioquímica, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brazil
| | - André L A Dos-Santos
- Laboratório de Bioquímica Celular, Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | - Cláudia F Dick
- Laboratório de Bioquímica Celular, Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto de Biofísica Carlos Chagas Filho, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | - José Roberto Meyer-Fernandes
- Laboratório de Bioquímica Celular, Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil.
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Schubert M, Spiegel H, Schillberg S, Nölke G. Aspergillus-specific antibodies - Targets and applications. Biotechnol Adv 2018; 36:1167-1184. [PMID: 29608951 DOI: 10.1016/j.biotechadv.2018.03.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 03/21/2018] [Accepted: 03/22/2018] [Indexed: 12/16/2022]
Abstract
Aspergillus is a fungal genus comprising several hundred species, many of which can damage the health of plants, animals and humans by direct infection and/or due to the production of toxic secondary metabolites known as mycotoxins. Aspergillus-specific antibodies have been generated against polypeptides, polysaccharides and secondary metabolites found in the cell wall or secretions, and these can be used to detect and monitor infections or to quantify mycotoxin contamination in food and feed. However, most Aspergillus-specific antibodies are generated against heterogeneous antigen preparations and the specific target remains unknown. Target identification is important because this can help to characterize fungal morphology, confirm host penetration by opportunistic pathogens, detect specific disease-related biomarkers, identify new candidate targets for antifungal drug design, and qualify antibodies for diagnostic and therapeutic applications. In this review, we discuss how antibodies are raised against heterogeneous Aspergillus antigen preparations and how they can be characterized, focusing on strategies to identify their specific antigens and epitopes. We also discuss the therapeutic, diagnostic and biotechnological applications of Aspergillus-specific antibodies.
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Affiliation(s)
- Max Schubert
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstrasse 6, 52074 Aachen, Germany
| | - Holger Spiegel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstrasse 6, 52074 Aachen, Germany
| | - Stefan Schillberg
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstrasse 6, 52074 Aachen, Germany; Justus-Liebig University Giessen, Institute for Phytopathology and Applied Zoology, Phytopathology Department, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany.
| | - Greta Nölke
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstrasse 6, 52074 Aachen, Germany
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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: 17] [Impact Index Per Article: 2.8] [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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14
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Abstract
Aspergillus fumigatus is an environmental filamentous fungus that can cause life-threatening disease in immunocompromised individuals. The interactions between A. fumigatus and the host environment are dynamic and complex. The host immune system needs to recognize the distinct morphological forms of A. fumigatus to control fungal growth and prevent tissue invasion, whereas the fungus requires nutrients and needs to adapt to the hostile environment by escaping immune recognition and counteracting host responses. Understanding these highly dynamic interactions is necessary to fully understand the pathogenesis of aspergillosis and to facilitate the design of new therapeutics to overcome the morbidity and mortality caused by A. fumigatus. In this Review, we describe how A. fumigatus adapts to environmental change, the mechanisms of host defence, and our current knowledge of the interplay between the host immune response and the fungus.
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15
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Abstract
Extracellular vesicles (EVs) are produced by virtually all cell types. Within the past few years, work in this field has revealed more information about fungal EVs. Fungal EVs have been shown to carry proteins, lipids, pigments, polysaccharides, and RNA; these components are known virulence factors, a fact which supports the hypothesis that fungal EVs concentrate pathogenic determinants. Additionally, recent studies have demonstrated that fungal EVs stimulate the host immune system. In this review, putative roles of fungal EVs are discussed, including their potential as vaccination tools and their possible contribution to pathogenesis in invasive fungal diseases.
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16
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Souza AA, Leitão VO, Ramada MH, Mehdad A, Georg RDC, Ulhôa CJ, de Freitas SM. Trichoderma harzianum Produces a New Thermally Stable Acid Phosphatase, with Potential for Biotechnological Application. PLoS One 2016; 11:e0150455. [PMID: 26938873 PMCID: PMC4777480 DOI: 10.1371/journal.pone.0150455] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 02/12/2016] [Indexed: 11/18/2022] Open
Abstract
Acid phosphatases (ACPases) are produced by a variety of fungi and have gained attention due their biotechnological potential in industrial, diagnosis and bioremediation processes. These enzymes play a specific role in scavenging, mobilization and acquisition of phosphate, enhancing soil fertility and plant growth. In this study, a new ACPase from Trichoderma harzianum, named ACPase II, was purified and characterized as a glycoprotein belonging to the acid phosphatase family. ACPase II presents an optimum pH and temperature of 3.8 and 65 °C, respectively, and is stable at 55 °C for 120 min, retaining 60% of its activity. The enzyme did not require metal divalent ions, but was inhibited by inorganic phosphate and tungstate. Affinity for several phosphate substrates was observed, including phytate, which is the major component of phosphorus in plant foods. The inhibition of ACPase II by tungstate and phosphate at different pH values is consistent with the inability of the substrate to occupy its active site due to electrostatic contacts that promote conformational changes, as indicated by fluorescence spectroscopy. A higher affinity for tungstate rather than phosphate at pH 4.0 was observed, in accordance with its highest inhibitory effect. Results indicate considerable biotechnological potential of the ACPase II in soil environments.
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Affiliation(s)
- Amanda Araújo Souza
- Laboratory of Biophysics, Department of Cellular Biology, University of Brasília, 70910-900, Brasília, Brazil
| | - Vanessa Oliveira Leitão
- Laboratory of Enzymology, Department of Cellular Biology, University of Brasília, 70910-900, Brasília, Brazil
| | - Marcelo Henrique Ramada
- Laboratory of Mass Espectrometry, Embrapa Recursos Genéticos e Biotecnologia – 70770-917, Brasília, Brazil
| | - Azadeh Mehdad
- Laboratory of Biophysics, Department of Cellular Biology, University of Brasília, 70910-900, Brasília, Brazil
| | - Raphaela de Castro Georg
- Laboratory of Enzymology, Institute of Biology, University Federal of Goiás, 74001-970, Goiania, Brazil
| | - Cirano José Ulhôa
- Laboratory of Enzymology, Institute of Biology, University Federal of Goiás, 74001-970, Goiania, Brazil
| | - Sonia Maria de Freitas
- Laboratory of Biophysics, Department of Cellular Biology, University of Brasília, 70910-900, Brasília, Brazil
- * E-mail:
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17
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Identification of Aph1, a phosphate-regulated, secreted, and vacuolar acid phosphatase in Cryptococcus neoformans. mBio 2014; 5:e01649-14. [PMID: 25227465 PMCID: PMC4172073 DOI: 10.1128/mbio.01649-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cryptococcus neoformans strains isolated from patients with AIDS secrete acid phosphatase, but the identity and role of the enzyme(s) responsible have not been elucidated. By combining a one-dimensional electrophoresis step with mass spectrometry, a canonically secreted acid phosphatase, CNAG_02944 (Aph1), was identified in the secretome of the highly virulent serotype A strain H99. We created an APH1 deletion mutant (Δaph1) and showed that Δaph1-infected Galleria mellonella and mice survived longer than those infected with the wild type (WT), demonstrating that Aph1 contributes to cryptococcal virulence. Phosphate starvation induced APH1 expression and secretion of catalytically active acid phosphatase in the WT, but not in the Δaph1 mutant, indicating that Aph1 is the major extracellular acid phosphatase in C. neoformans and that it is phosphate repressible. DsRed-tagged Aph1 was transported to the fungal cell periphery and vacuoles via endosome-like structures and was enriched in bud necks. A similar pattern of Aph1 localization was observed in cryptococci cocultured with THP-1 monocytes, suggesting that Aph1 is produced during host infection. In contrast to Aph1, but consistent with our previous biochemical data, green fluorescent protein (GFP)-tagged phospholipase B1 (Plb1) was predominantly localized at the cell periphery, with no evidence of endosome-mediated export. Despite use of different intracellular transport routes by Plb1 and Aph1, secretion of both proteins was compromised in a Δsec14-1 mutant. Secretions from the WT, but not from Δaph1, hydrolyzed a range of physiological substrates, including phosphotyrosine, glucose-1-phosphate, β-glycerol phosphate, AMP, and mannose-6-phosphate, suggesting that the role of Aph1 is to recycle phosphate from macromolecules in cryptococcal vacuoles and to scavenge phosphate from the extracellular environment. Infections with the AIDS-related fungal pathogen Cryptococcus neoformans cause more than 600,000 deaths per year worldwide. Strains of Cryptococcus neoformans isolated from patients with AIDS secrete acid phosphatase; however, the identity and role of the enzyme(s) are unknown. We have analyzed the secretome of the highly virulent serotype A strain H99 and identified Aph1, a canonically secreted acid phosphatase. By creating an APH1 deletion mutant and an Aph1-DsRed-expressing strain, we demonstrate that Aph1 is the major extracellular and vacuolar acid phosphatase in C. neoformans and that it is phosphate repressible. Furthermore, we show that Aph1 is produced in cryptococci during coculture with THP-1 monocytes and contributes to fungal virulence in Galleria mellonella and mouse models of cryptococcosis. Our findings suggest that Aph1 is secreted to the environment to scavenge phosphate from a wide range of physiological substrates and is targeted to vacuoles to recycle phosphate from the expendable macromolecules.
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18
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Lim FY, Ames B, Walsh CT, Keller NP. Co-ordination between BrlA regulation and secretion of the oxidoreductase FmqD directs selective accumulation of fumiquinazoline C to conidial tissues in Aspergillus fumigatus. Cell Microbiol 2014; 16:1267-83. [PMID: 24612080 DOI: 10.1111/cmi.12284] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 02/11/2014] [Accepted: 02/12/2014] [Indexed: 01/18/2023]
Abstract
Aerial spores, crucial for propagation and dispersal of the Kingdom Fungi, are commonly the initial inoculum of pathogenic fungi. Natural products (secondary metabolites) have been correlated with fungal spore development and enhanced virulence in the human pathogen Aspergillus fumigatus but mechanisms for metabolite deposition in the spore are unknown. Metabolomic profiling of A. fumigatus deletion mutants of fumiquinazoline (Fq) cluster genes reveal that the first two products of the Fq cluster, FqF and FqA, are produced to comparable levels in all fungal tissues but the final enzymatically derived product, FqC, predominantly accumulates in the fungal spore. Loss of the sporulation-specific transcription factor, BrlA, yields a strain unable to produce FqA or FqC. Fluorescence microscopy showed FmqD, the oxidoreductase required to generate FqC, was secreted via the Golgi apparatus to the cell wall in an actin-dependent manner. In contrast, all other members of the Fq pathway including the putative transporter, FmqE - which had no effect on Fq biosynthesis - were internal to the hyphae. The co-ordination of BrlA-mediated tissue specificity with FmqD secretion to the cell wall presents a previously undescribed mechanism to direct localization of specific secondary metabolites to spores of the differentiating fungus.
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Affiliation(s)
- Fang Yun Lim
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
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19
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Biochemical properties and possible roles of ectophosphatase activities in fungi. Int J Mol Sci 2014; 15:2289-304. [PMID: 24509700 PMCID: PMC3958851 DOI: 10.3390/ijms15022289] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 11/27/2013] [Accepted: 01/14/2014] [Indexed: 12/31/2022] Open
Abstract
Ectophosphatases are surface membrane-bound proteins whose active sites face the extracellular medium. These enzymes have been reported in several microorganisms including a large number of medically relevant fungal species. An effective technique for identifying ectophosphatases is performing phosphatase activity assays using living intact cells. Biochemical characterization of these activities has shown their differential modulation by classical phosphatase inhibitors, divalent metals and pH range. The physiological roles of ectophosphatases are not well established; however, it has been suggested that these enzymes play important roles in nutrition, proliferation, differentiation, adhesion, virulence and infection. Adhesion to host cells is the first step in establishing a fungal infection and ectophosphatases may be one of the first parasite proteins that come into contact with the host cells. Several results indicate that ectophosphatase activities increase the capacity of fungi to adhere to the host cells. In this context, the present review provides an overview of recent discoveries related to the occurrence and possible roles of ectophosphatase activities in fungal cells.
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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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Cosentino-Gomes D, Rocco-Machado N, Santi L, Broetto L, Vainstein MH, Meyer-Fernandes JR, Schrank A, Beys-da-Silva WO. Inhibition of ecto-phosphatase activity in conidia reduces adhesion and virulence of Metarhizium anisopliae on the host insect Dysdercus peruvianus. Curr Microbiol 2013; 66:467-74. [PMID: 23306352 DOI: 10.1007/s00284-012-0296-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 12/03/2012] [Indexed: 01/17/2023]
Abstract
Metarhizium anisopliae is an entomopathogenic fungus with the ability to infect a broad range of arthropods, and have evolved distinct strategies for their attachment to hosts. Here, we describe the characterisation of ecto-phosphatase activity on the conidia surface of M. anisopliae and its relevance in the host interaction process. Ecto-phosphatase activity was linear for 60 min and during this time, was linear with the increase of cell density. The optimum pH was in the acidic range and some divalent metals, such as Cu(2+), Cd(2+) and Zn(2+), inhibited ecto-phosphatase activity. The activity was also reduced by phosphatase inhibitors. Importantly, the inhibition of phosphatase activity in conidia reduced the adhesion to Dysdercus peruvianus (Hemiptera: Pyrrhocoridae) integument and, consequently and indirectly, M. anisopliae infection. The results herein presented show, for the first time, the importance of ecto-phosphatase activity in M. anisopliae conidia and provide the first evidence of its direct involvement in adhesion and host infection.
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Affiliation(s)
- Daniela Cosentino-Gomes
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, CCS, Bloco H, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ 21941-902, Brazil
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22
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Sousa Lima P, Bailão EFLC, Silva MG, Castro NDS, Báo SN, Orlandi I, Vai M, Almeida Soares CM. Characterization of the Paracoccidioides beta-1,3-glucanosyltransferase family. FEMS Yeast Res 2012; 12:685-702. [DOI: 10.1111/j.1567-1364.2012.00819.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 05/29/2012] [Accepted: 06/06/2012] [Indexed: 11/24/2022] Open
Affiliation(s)
- Patrícia Sousa Lima
- Laboratório de Biologia Molecular; Instituto de Ciências Biológicas; Universidade Federal de Goiás; Goiás; Brazil
| | | | - Mirelle Garcia Silva
- Laboratório de Biologia Molecular; Instituto de Ciências Biológicas; Universidade Federal de Goiás; Goiás; Brazil
| | - Nadya da Silva Castro
- Laboratório de Biologia Molecular; Instituto de Ciências Biológicas; Universidade Federal de Goiás; Goiás; Brazil
| | - Sônia Nair Báo
- Laboratório de Microscopia Eletrônica; Universidade de Brasília; Brasília; Brazil
| | - Ivan Orlandi
- Dipartimento di Biotecnologie e Bioscienze; Università degli Studi di Milano-Bicocca; Milan; Italy
| | - Marina Vai
- Dipartimento di Biotecnologie e Bioscienze; Università degli Studi di Milano-Bicocca; Milan; Italy
| | - Célia Maria Almeida Soares
- Laboratório de Biologia Molecular; Instituto de Ciências Biológicas; Universidade Federal de Goiás; Goiás; Brazil
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23
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A glycosylphosphatidylinositol anchor is required for membrane localization but dispensable for cell wall association of chitin deacetylase 2 in Cryptococcus neoformans. mBio 2012; 3:mBio.00007-12. [PMID: 22354955 PMCID: PMC3280450 DOI: 10.1128/mbio.00007-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Cell wall proteins (CWPs) mediate important cellular processes in fungi, including adhesion, invasion, biofilm formation, and flocculation. The current model of fungal cell wall organization includes a major class of CWPs covalently bound to β-1,6-glucan via a remnant of a glycosylphosphatidylinositol (GPI) anchor. This model was established by studies of ascomycetes more than a decade ago, and relatively little work has been done with other fungi, although the presumption has been that proteins identified in the cell wall which contain a predicted GPI anchor are covalently linked to cell wall glucans. The pathogenic basidiomycete Cryptococcus neoformans encodes >50 putatively GPI-anchored proteins, some of which have been identified in the cell wall. One of these proteins is chitin deacetylase 2 (Cda2), an enzyme responsible for converting chitin to chitosan, a cell wall polymer recently established as a virulence factor for C. neoformans infection of mammalian hosts. Using a combination of biochemistry, molecular biology, and genetics, we show that Cda2 is GPI anchored to membranes but noncovalently associated with the cell wall by means independent of both its GPI anchor and β-1,6-glucan. We also show that Cda2 produces chitosan when localized to the plasma membrane, but association with the cell wall is not essential for this process, thereby providing insight into the mechanism of chitosan biosynthesis. These results increase our understanding of the surface of C. neoformans and provide models of cell walls likely applicable to other undercharacterized basidiomycete pathogenic fungi. The surface of a pathogenic microbe is a major interface with its host. In fungi, the outer surface consists of a complex matrix known as the cell wall, which includes polysaccharides, proteins, and other molecules. The mammalian host recognizes many of these surface molecules and mounts appropriate responses to combat the microbial infection. Cryptococcus neoformans is a serious fungal pathogen that kills over 600,000 people annually. It converts most of its chitin, a cell wall polysaccharide, to chitosan, which is necessary for virulence. Chitin deacetylase enzymes have been identified in the cell wall, and our studies were undertaken to understand how the deacetylase is linked to the wall and where it has activity. Our results have implications for the current model of chitosan biosynthesis and further challenge the paradigm of covalent linkages between cell wall proteins and polysaccharides through a lipid modification of the protein.
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24
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Pritsch K, Courty PE, Churin JL, Cloutier-Hurteau B, Ali MA, Damon C, Duchemin M, Egli S, Ernst J, Fraissinet-Tachet L, Kuhar F, Legname E, Marmeisse R, Müller A, Nikolova P, Peter M, Plassard C, Richard F, Schloter M, Selosse MA, Franc A, Garbaye J. Optimized assay and storage conditions for enzyme activity profiling of ectomycorrhizae. MYCORRHIZA 2011; 21:589-600. [PMID: 21344212 DOI: 10.1007/s00572-011-0364-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Accepted: 01/28/2011] [Indexed: 05/30/2023]
Abstract
The aim of a joint effort by different research teams was to provide an improved procedure for enzyme activity profiling of field-sampled ectomycorrhizae, including recommendations on the best conditions and maximum duration for storage of ectomycorrhizal samples. A more simplified and efficient protocol compared to formerly published procedures was achieved by using manufactured 96-filter plates in combination with a vacuum manifold and by optimizing incubation times. Major improvements were achieved by performing the series of eight enzyme assays with a single series of root samples instead of two series, reducing the time needed for sample preparation, minimizing error-prone steps such as pipetting and morphotyping, and facilitating subsequent DNA analyses due to the reduced sequencing effort. The best preservation of samples proved to be storage in soil at 4-6 °C in the form of undisturbed soil cores containing roots. Enzyme activities were maintained for up to 4 weeks under these conditions. Short-term storage of washed roots and ectomycorrhizal tips overnight in water did not cause substantial changes in enzyme activity profiles. No optimal means for longer-term storage by freezing at -20 °C or storage in 100% ethanol were recommended.
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Affiliation(s)
- Karin Pritsch
- Institute of Soil Ecology, German Research Center for Environmental Health (GmbH), 85764, Neuherberg, Germany.
| | - Pierre Emanuel Courty
- UMR 1136, Interactions Arbres Micro-organismes, Centre INRA de Nancy, 54280, Champenoux, France
- Botanical Institute, University of Basel, 4056, Basel, Switzerland
| | - Jean-Louis Churin
- UMR 1136, Interactions Arbres Micro-organismes, Centre INRA de Nancy, 54280, Champenoux, France
| | - Benoit Cloutier-Hurteau
- UMR 1222, Ecologie Fonctionelle et Biogéochimie des Sols, INRA/IRD/SupAgro, 34060, Montpellier Cedex 01, France
| | - Muhammad Arif Ali
- UMR 1222, Ecologie Fonctionelle et Biogéochimie des Sols, INRA/IRD/SupAgro, 34060, Montpellier Cedex 01, France
| | - Coralie Damon
- UMR CNRS 5557 d'Ecologie Microbienne, Université de Lyon, Université Lyon 1, 69622, Villeurbanne Cedex, France
| | - Myriam Duchemin
- UMR 1222, Ecologie Fonctionelle et Biogéochimie des Sols, INRA/IRD/SupAgro, 34060, Montpellier Cedex 01, France
| | - Simon Egli
- Swiss Federal Research Institute WSL, 8903, Birmensdorf, Switzerland
| | - Jana Ernst
- Institute of Soil Ecology, Terrestrial Ecogenetics, German Research Center for Environmental Health (GmbH), 85764, Neuherberg, Germany
| | - Laurence Fraissinet-Tachet
- UMR CNRS 5557 d'Ecologie Microbienne, Université de Lyon, Université Lyon 1, 69622, Villeurbanne Cedex, France
| | - Francisco Kuhar
- Biodiversidad y Biología Experimental, CABA, Universidad de Buenos Aires, Buenos Aires, 1428, Argentina
- Institute of Soil Ecology, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764, Neuherberg, Germany
| | - Elvira Legname
- UMR 1222, Ecologie Fonctionelle et Biogéochimie des Sols, INRA/IRD/SupAgro, 34060, Montpellier Cedex 01, France
| | - Roland Marmeisse
- UMR CNRS 5557 d'Ecologie Microbienne, Université de Lyon, Université Lyon 1, 69622, Villeurbanne Cedex, France
| | - Alex Müller
- Swiss Federal Research Institute WSL, 8903, Birmensdorf, Switzerland
| | - Petia Nikolova
- Institute of Soil Ecology, German Research Center for Environmental Health (GmbH), 85764, Neuherberg, Germany
| | - Martina Peter
- Swiss Federal Research Institute WSL, 8903, Birmensdorf, Switzerland
| | - Claude Plassard
- UMR 1222, Ecologie Fonctionelle et Biogéochimie des Sols, INRA/IRD/SupAgro, 34060, Montpellier Cedex 01, France
| | - Franck Richard
- UMR 5175, Centre d'Ecologie Fonctionnelle et Evolutive, 34293, Montpellier 5, France
| | - Michael Schloter
- Institute of Soil Ecology, Terrestrial Ecogenetics, German Research Center for Environmental Health (GmbH), 85764, Neuherberg, Germany
| | - Marc-André Selosse
- UMR 5175, Centre d'Ecologie Fonctionnelle et Evolutive, 34293, Montpellier 5, France
| | - Alain Franc
- UMR Biodivers Genes & Communautes, INRA Pierroton, 33612, Cestas, France
| | - Jean Garbaye
- UMR 1136, Interactions Arbres Micro-organismes, Centre INRA de Nancy, 54280, Champenoux, France
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25
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Dick CF, Dos-Santos ALA, Meyer-Fernandes JR. Inorganic phosphate as an important regulator of phosphatases. Enzyme Res 2011; 2011:103980. [PMID: 21755037 PMCID: PMC3132463 DOI: 10.4061/2011/103980] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Accepted: 05/03/2011] [Indexed: 11/20/2022] Open
Abstract
Cellular metabolism depends on the appropriate concentration of intracellular inorganic phosphate (Pi). Pi starvation-responsive genes appear to be involved in multiple metabolic pathways, implying a complex Pi regulation system in microorganisms and plants. A group of enzymes is required for absorption and maintenance of adequate phosphate levels, which is released from phosphate esters and anhydrides. The phosphatase system is particularly suited for the study of regulatory mechanisms because phosphatase activity is easily measured using specific methods and the difference between the repressed and derepressed levels of phosphatase activity is easily detected. This paper analyzes the protein phosphatase system induced during phosphate starvation in different organisms.
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Affiliation(s)
- Claudia Fernanda Dick
- Instituto de Microbiologia Professor Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brazil
- Laboratório de Bioquímica Celular, Instituto de Bioquímica Medica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brazil
| | - André Luiz Araújo Dos-Santos
- Laboratório de Bioquímica Celular, Instituto de Bioquímica Medica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brazil
| | - José Roberto Meyer-Fernandes
- Laboratório de Bioquímica Celular, Instituto de Bioquímica Medica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brazil
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Possible roles of ectophosphatases in host-parasite interactions. J Parasitol Res 2011; 2011:479146. [PMID: 21603194 PMCID: PMC3095255 DOI: 10.1155/2011/479146] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Revised: 02/07/2011] [Accepted: 03/01/2011] [Indexed: 11/17/2022] Open
Abstract
The interaction and survival of pathogens in hostile environments and in confrontation with host immune responses are important mechanisms for the establishment of infection. Ectophosphatases are enzymes localized at the plasma membrane of cells, and their active sites face the external medium rather than the cytoplasm. Once activated, these enzymes are able to hydrolyze phosphorylated substrates in the extracellular milieu. Several studies demonstrated the presence of surface-located ecto-phosphatases in a vast number of pathogenic organisms, including bacteria, protozoa, and fungi. Little is known about the role of ecto-phosphatases in host-pathogen interactions. The present paper provides an overview of recent findings related to the virulence induced by these surface molecules in protozoa and fungi.
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27
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Vieira DP, Paletta-Silva R, Saraiva EM, Lopes AH, Meyer-Fernandes JR. Leishmania chagasi: An ecto-3′-nucleotidase activity modulated by inorganic phosphate and its possible involvement in parasite–macrophage interaction. Exp Parasitol 2011; 127:702-7. [DOI: 10.1016/j.exppara.2010.11.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 09/03/2010] [Accepted: 11/10/2010] [Indexed: 01/22/2023]
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28
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Louche J, Ali MA, Cloutier-Hurteau B, Sauvage FX, Quiquampoix H, Plassard C. Efficiency of acid phosphatases secreted from the ectomycorrhizal fungus Hebeloma cylindrosporum to hydrolyse organic phosphorus in podzols. FEMS Microbiol Ecol 2010; 73:323-35. [PMID: 20533944 DOI: 10.1111/j.1574-6941.2010.00899.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Ectomycorrhizal fungi may improve the phosphate nutrition of their host plants by secreting, into the soil solution, acid phosphatases (AcPases) able to release orthophosphate (Pi) from soil organic phosphorus (Po). Using cation-exchange chromatography, we separated four fractions with AcPase activity secreted by the ectomycorrhizal fungus Hebeloma cylindrosporum grown in a pure culture under P-starved conditions. Each AcPase active fraction displayed strong ability in vitro to hydrolyse a wide range of phosphate monoesters, but none of them efficiently hydrolysed phytate. Their efficiency to release Pi from soil NaHCO(3)-extractable Po was studied in a sandy podzol used intact or autoclaved. Soils were collected in a 15-year-old Pinus pinaster stand, receiving regular fertilization or not. Autoclaving increased the NaHCO(3)-extractable Po concentrations by 55% in unfertilized and by 32-43% in fertilized soils. The efficiency of each AcPase fraction was affected significantly by the soil fertilization regime and the soil treatment (intact vs. autoclaved). The proportion of labile Po enzyme ranged from 0% to 11% and 14% to 48% after 1 h of incubation in bicarbonate solutions extracted from intact and autoclaved soils, respectively. This work suggests that AcPases secreted from H. cylindrosporum could be efficient in recycling Po pools from soil microorganisms that may be delivered by soil autoclaving.
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Affiliation(s)
- Julien Louche
- UMR 1222 Ecologie Fonctionnelle et Biogéochimie des Sols (INRA-IRD-SupAgro, UMR 210), Montpellier, France
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29
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Purification and characterization of an acid phosphatase from Trichoderma harzianum. Biotechnol Lett 2010; 32:1083-8. [DOI: 10.1007/s10529-010-0264-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Accepted: 03/23/2010] [Indexed: 10/19/2022]
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30
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Trypanosoma rangeli: Differential expression of ecto-phosphatase activities in response to inorganic phosphate starvation. Exp Parasitol 2010; 124:386-93. [DOI: 10.1016/j.exppara.2009.12.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Revised: 11/16/2009] [Accepted: 12/12/2009] [Indexed: 01/25/2023]
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31
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Portela MB, Kneipp LF, Ribeiro de Souza IP, Holandino C, Alviano CS, Meyer-Fernandes JR, De Araújo Soares RM. Ectophosphatase activity in Candida albicans influences fungal adhesion: study between HIV-positive and HIV-negative isolates. Oral Dis 2010; 16:431-7. [DOI: 10.1111/j.1601-0825.2009.01644.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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32
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Müller IB, Knöckel J, Eschbach ML, Bergmann B, Walter RD, Wrenger C. Secretion of an acid phosphatase provides a possible mechanism to acquire host nutrients by Plasmodium falciparum. Cell Microbiol 2010; 12:677-91. [PMID: 20070315 DOI: 10.1111/j.1462-5822.2010.01426.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
As an intracellular proliferating parasite, Plasmodium falciparum exploits the human host to acquire nutrients. However, nutrients such as nucleotides and cofactors are mostly phosphorylated in the host cell cytosol and thus have to be dephosphorylated in order to be taken up by the parasite. Here we report the functional characterization of a unique secreted phosphatase in P. falciparum, which is expressed throughout the developmental stages in the red blood cell. We show that this enzyme, formerly described as anchoring glideosome-associated protein 50 (GAP50), reveals a broad substrate profile with preference for di- and triphosphates at pH 5-7. Bioinformatic studies of the protein sequence identified an N-terminal signal anchor (SA) as well as a C-terminal transmembrane domain. By means of live microscopy of parasites transfected with GFP-fusions of this secreted acid phosphatase (PfSAP), we demonstrate that PfSAP enters the secretory pathway en route to the parasite periphery - mediated by SA - and is subsequently engulfed into the food vacuole. We corroborate this with independent data where acid phosphatase activity is visualized in close proximity to hemozoin. The biochemical as well as the trafficking results support the proposed role of PfSAP in the acquisition of host nutrients by dephosphorylation.
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Affiliation(s)
- Ingrid B Müller
- Bernhard Nocht Institute for Tropical Medicine, Department of Biochemistry, Hamburg, Germany.
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33
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Prados-Rosales R, Luque-Garcia JL, Martínez-López R, Gil C, Di Pietro A. The Fusarium oxysporum
cell wall proteome under adhesion-inducing conditions. Proteomics 2009; 9:4755-69. [DOI: 10.1002/pmic.200800950] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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34
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Trypanosoma rangeli: A possible role for ecto-phosphatase activity on cell proliferation. Exp Parasitol 2009; 122:242-6. [DOI: 10.1016/j.exppara.2009.03.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Revised: 01/06/2009] [Accepted: 03/06/2009] [Indexed: 12/16/2022]
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35
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El-Shora HM, Metwally M. Effect of Phytohormones and Group Selective Reagents on Acid Phosphatase from Cladosporium cladosporioides. ACTA ACUST UNITED AC 2008. [DOI: 10.3923/ajbkr.2009.1.11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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36
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Taylor RD, Saparno A, Blackwell B, Anoop V, Gleddie S, Tinker NA, Harris LJ. Proteomic analyses of Fusarium graminearum grown under mycotoxin-inducing conditions. Proteomics 2008; 8:2256-65. [PMID: 18452225 DOI: 10.1002/pmic.200700610] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Non-gel-based quantitative proteomics technology was used to profile protein expression differences when Fusarium graminearum was induced to produce trichothecenes in vitro. As F. graminearum synthesizes and secretes trichothecenes early in the cereal host invasion process, we hypothesized that proteins contributing to infection would also be induced under conditions favouring mycotoxin synthesis. Protein samples were extracted from three biological replicates of a time course study and subjected to iTRAQ (isobaric tags for relative and absolute quantification) analysis. Statistical analysis of a filtered dataset of 435 proteins revealed 130 F. graminearum proteins that exhibited significant changes in expression, of which 72 were upregulated relative to their level at the initial phase of the time course. There was good agreement between upregulated proteins identified by 2-D PAGE/MS/MS and iTRAQ. RT-PCR and northern hybridization confirmed that genes encoding proteins which were upregulated based on iTRAQ were also transcriptionally active under mycotoxin producing conditions. Numerous candidate pathogenicity proteins were identified using this technique. These will provide leads in the search for mechanisms and markers of host invasion and novel antifungal targets.
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Affiliation(s)
- Rebecca D Taylor
- Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, Ottawa, Ontario, Canada
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37
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Fonseca-de-Souza AL, Dick CF, Dos Santos ALA, Meyer-Fernandes JR. A Mg(2+)-dependent ecto-phosphatase activity on the external surface of Trypanosoma rangeli modulated by exogenous inorganic phosphate. Acta Trop 2008; 107:153-8. [PMID: 18599005 DOI: 10.1016/j.actatropica.2008.05.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Revised: 05/16/2008] [Accepted: 05/22/2008] [Indexed: 11/30/2022]
Abstract
In this work, we characterized a Mg(2+)-dependent ecto-phosphatase activity present in live Trypanosoma rangeli epimastigotes. This enzyme showed capacity to hydrolyze the artificial substrate for phosphatases, p-nitrophenylphosphate (p-NPP). At saturating concentration of p-NPP, half-maximal p-NPP hydrolysis was obtained with 0.23mM Mg(2+). Ca(2+) had no effect on the basal phosphatase activity, could not substitute Mg(2+) as an activator and in contrast inhibited the p-NPP hydrolysis stimulated by Mg(2+). The dependence on p-NPP concentration showed a normal Michaelis-Menten kinetics for this phosphatase activity with values of V(max) of 8.94+/-0.36 nmol p-NP x h(-1) x 10(-7) cells and apparent K(m) of 1.04+/-0.16 mM p-NPP. Mg(2+)-dependent ecto-phosphatase activity was stimulated by the alkaline pH range. Experiments using inhibitors, such as, sodium fluoride, sodium orthovanadate and ammonium molybdate, inhibited the Mg(2+)-dependent ecto-phosphatase activity. Inorganic phosphate (Pi), a product of phosphatases, inhibited reversibly in 50% this activity. Okadaic acid and microcystin-LR, specific phosphoserine/threonine phosphatase inhibitors, inhibited significantly the Mg(2+)-dependent ecto-phosphatase activity. In addition, this phosphatase activity was able to recognize as substrates only o-phosphoserine and o-phosphothreonine, while o-phosphotyrosine was not a good substrate for this phosphatase. Epimastigote forms of T. rangeli exhibit a typical growth curve, achieving the stationary phase around fifth or sixth day and the Mg(2+)-dependent ecto-phosphatase activity decreased around 10-fold with the cell growth progression. Cells maintained at Pi-deprived medium (2 mM Pi) present Mg(2+)-dependent ecto-phosphatase activity approximately threefold higher than that maintained at Pi-supplemented medium (50 mM Pi).
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Affiliation(s)
- André L Fonseca-de-Souza
- Laboratório de Bioquímica Celular, Instituto de Bioquímica Medica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, UFRJ, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ, Brazil
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38
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Abstract
The cell wall is composed of a polysaccharide-based three-dimensional network. Considered for a long time as an inert exoskeleton, the cell wall is now seen as a dynamic structure that is continuously changing as a result of the modification of culture conditions and environmental stresses. Although the cell wall composition varies among fungal species, chemogenomic comparative analysis have led to a better understanding of the genes and mechanisms involved in the construction of the common central core composed of branched beta1,3 glucan-chitin. Because of its essential biological role, unique biochemistry and structural organization and the absence in mammalian cells of most of its constitutive components, the cell wall is an attractive target for the development of new antifungal agents. Genomic as well as drug studies have shown that the death of the fungus can result from inhibition of cell wall polysaccharide synthases. To date, only beta1,3 glucan synthase inhibitors have been launched clinically and many more targets remain to be explored.
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Affiliation(s)
- Jean-Paul Latgé
- Unite des Aspergillus, Institut Pasteur, 25, rue du Dr Roux, 75015 Paris, France.
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39
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Xander P, Vigna AF, Feitosa LDS, Pugliese L, Bailão AM, Soares CMDA, Mortara RA, Mariano M, Lopes JD. A surface 75-kDa protein with acid phosphatase activity recognized by monoclonal antibodies that inhibit Paracoccidioides brasiliensis growth. Microbes Infect 2007; 9:1484-92. [PMID: 17913543 DOI: 10.1016/j.micinf.2007.08.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Revised: 07/26/2007] [Accepted: 08/05/2007] [Indexed: 11/20/2022]
Abstract
Paracoccidioides brasiliensis is a thermo-dimorphic fungus responsible for paracoccidioidomycosis (PCM), a systemic granulomatous mycosis prevalent in Latin America. The fungus releases many antigens which may be transiently bound to its cell surface. Some of them may show enzymatic functions essential for maintaining many cell processes and survival of the microorganism at different conditions. In this study, we report the characterization of a secreted 75kDa protein from P. brasiliensis with phosphatase activity. Biologic function of the molecule was demonstrated using two specific mAbs produced and characterized as IgM and IgG isotypes. Confocal microscopy and flow cytometry analysis demonstrated that both mAbs recognized the protein on the fungus surface, mainly in its budding sites. In vitro experiments showed that fungal growth was inhibited by blocking the protein with mAbs. In addition, opsonized yeast cells with both mAbs facilitated phagocytosis by murine peritoneal macrophages. Passive immunization using mAbs before P. brasiliensis mice infection reduced colony-forming units (CFU) in the lungs as compared with controls. Histopathology showed smaller inflammation, absence of yeast cells and no granuloma formation.
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Affiliation(s)
- Patrícia Xander
- Disciplina de Imunologia, Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, UNIFESP, Rua Botucatu 862, 04023-901 São Paulo, Brazil
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40
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Kiffer-Moreira T, de Sá Pinheiro AA, Alviano WS, Barbosa FM, Souto-Padrón T, Nimrichter L, Rodrigues ML, Alviano CS, Meyer-Fernandes JR. An ectophosphatase activity inCandida parapsilosisinfluences the interaction of fungi with epithelial cells. FEMS Yeast Res 2007; 7:621-8. [PMID: 17419773 DOI: 10.1111/j.1567-1364.2007.00223.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
This study describes the biochemical characterization of a phosphatase activity present on the cell surface of Candida parapsilosis, a common cause of candidemia. Intact yeasts hydrolyzed p-nitrophenylphosphate to p-nitrophenol at a rate of 24.30+/-2.63 nmol p-nitrophenol h(-1) 10(-7) cells. The cell wall distribution of the Ca. parapsilosis enzyme was demonstrated by transmission electron microscopy. The duration of incubation of the yeast cells with the substrate and cell density influenced enzyme activity linearly. Values of V(max) and apparent K(m) for p-nitrophenylphosphate hydrolysis were 26.80+/-1.13 nmol p-nitrophenol h(-1) 10(-7) cells and 0.47+/-0.05 mM p-nitrophenylphosphate, respectively. The ectophosphatase activity was strongly inhibited at high pH as well as by classical inhibitors of acid phosphatases, such as sodium orthovanadate, sodium molybdate, sodium fluoride, and inorganic phosphate, the final product of the reaction. Only the inhibition caused by sodium orthovanadate was irreversible. Different phophorylated amino acids were used as substrates for the Ca. parapsilosis ectoenzyme, and the highest rate of phosphate hydrolysis was achieved using phosphotyrosine. A direct relationship between ectophosphatase activity and adhesion to host cells was established. In these assays, irreversible inhibition of enzyme activity resulted in decreased levels of yeast adhesion to epithelial cells.
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Affiliation(s)
- Tina Kiffer-Moreira
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, Brazil
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41
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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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42
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Collopy-Junior I, Esteves FF, Nimrichter L, Rodrigues ML, Alviano CS, Meyer-Fernandes JR. An ectophosphatase activity in Cryptococcus neoformans. FEMS Yeast Res 2006; 6:1010-7. [PMID: 17042750 DOI: 10.1111/j.1567-1364.2006.00105.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
There is increasing evidence in the literature showing that fungal pathogens express biologically active ectoenzymes. The expression of surface phosphatases at the cell surface of Cryptococcus neoformans, the etiologic agent of cryptococcosis, was evaluated in the present study. Different isolates of C. neoformans express ectophosphatase activity, which is not influenced by capsule size or serotype. The cryptococcal enzyme is an acid phosphatase, inhibited by classic inhibitors of ectophosphatases, including ammonium molybdate and sodium salts of fluoride and orthovanadate. Only the inhibition of enzyme activity caused by sodium orthovanadate has been shown to be irreversible. The cryptococcal ectoenzyme is also inhibited by Zn2+ and inorganic phosphate, the final product of reactions catalyzed by phosphatases. The ectophosphatase from C. neoformans efficiently releases phosphate groups from different phosphorylated amino acids, giving a higher rate of phosphate removal when phosphothreonine is used as a substrate. Yeast cells with irreversibly inhibited ectophosphatases are less capable of adhering to animal epithelial cells than fungi fully expressing enzyme activity, suggesting that ectoenzyme expression can contribute to the pathogenesis of C. neoformans.
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Affiliation(s)
- Itallo Collopy-Junior
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, CCS, Bloco H, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ, Brazil
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43
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Krause K, Kothe E. Use of RNA fingerprinting to identify fungal genes specifically expressed during ectomycorrhizal interaction. J Basic Microbiol 2006; 46:387-99. [PMID: 17009294 DOI: 10.1002/jobm.200610153] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The ecosystem soil is characterized by interactions between microorganisms and plants including mycorrhiza--mutualistic interactions between fungi and plant roots. Species of the basidiomycete genus Tricholoma form ectomycorrhiza with tree roots which is characterized by morphological and metabolic changes of both partners, yet molecular mechanisms of the interaction are poorly understood. We performed differential display with arbitrarily primed RT-PCR using ectomycorrhiza between the basidiomycete Tricholoma vaccinum and its compatible host spruce (Picea abies) to isolate mycorrhiza-specific fungal gene fragments. 76 differentially expressed PCR fragments were verified and checked for plant or fungal origin and expression pattern. Of 20 fungal fragments with mycorrhiza-specific expression, sequence analyses were performed to identify homologs with known function of the encoded protein. Among the genes identified were orthologs to an aldehyde dehydrogenase, an alcohol dehydrogenase and a protein of the MATE transporter family, all with possible function in plant pathogen response. A phospholipase B, a beta-glucosidase and a binding protein of basic amino acids might play a role in nutrient exchange and growth in planta. A protein similar to inactive E2 compounds of ubiquitin-conjugating enzymes like CROC-1 and MMS2, a Ras protein and an APS kinase were placed in signal transduction and two retrotransposons of the Ty3-gypsy and the Ty1-copia family are expressed most likely due to stress.
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Affiliation(s)
- Katrin Krause
- University of Jena, Dept. Microbiology, Microbial Phytopathology, Neugasse 25, D-07743 Jena, Germany.
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44
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Chabane S, Sarfati J, Ibrahim-Granet O, Du C, Schmidt C, Mouyna I, Prevost MC, Calderone R, Latgé JP. Glycosylphosphatidylinositol-anchored Ecm33p influences conidial cell wall biosynthesis in Aspergillus fumigatus. Appl Environ Microbiol 2006; 72:3259-67. [PMID: 16672465 PMCID: PMC1472355 DOI: 10.1128/aem.72.5.3259-3267.2006] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ECM33 encodes a glycosylphosphatidylinositol-anchored protein whose orthologs in yeast are essential for sporulation. Aspergillus fumigatus Ecm33p is unique and has an apparent mass of 55 kDa. Disruption of A. fumigatus ECM33 results in a mutant with several morphogenetic aberrations, including the following: (i) a defect in conidial separation, (ii) an increase in the diameter of the conidia of the mutant associated with an increase in the concentration of the cell wall chitin, (iii) conidia that were sensitive to the absence of aeration during long-term storage, and (iv) conidia that were more resistant to killing by phagocytes, whereas the mycelium was more easily killed by neutrophils.
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Affiliation(s)
- Sandrine Chabane
- Aspergillus Unit, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France
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45
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Tasaki Y, Azwan A, Yazaki J, Hara T, Joh T. Structure and expression of two genes encoding secreted acid phosphatases under phosphate-deficient conditions in Pholiota nameko strain N2. Curr Genet 2006; 49:323-32. [PMID: 16453113 DOI: 10.1007/s00294-006-0058-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Revised: 12/22/2005] [Accepted: 12/25/2005] [Indexed: 10/25/2022]
Abstract
Twenty-three polypeptides secreted in response to a deficiency of inorganic phosphate (Pi) were previously found by two-dimensional polyacrylamide gel electrophoresis analysis in mycelia of Pholiota nameko strain N2. In this study, N-terminal sequencing revealed three of them to be identical to known acid phosphatases of P. nameko strain N114. Two cDNAs and the corresponding genomic DNAs of genes PNAP1 and PNAP2 which encode two of the three acid phosphatases were cloned. The deduced amino acid sequences of PNAP1 and PNAP2 showed high similarity to other fungal acid phosphatases and contained a putative catalytic active site of acid phosphatase. PNAP1 and PNAP2 are comprised of five and seven exons interrupted by four and six introns, respectively. Their promoter regions include two cis-acting elements found in Pi deficiency-inducible genes of Saccharomyces cerevisiae, together with several known functional elements such as a TATA box. Northern blot analysis showed that PNAP1 and PNAP2 are expressed in response to a deficiency of Pi.
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Affiliation(s)
- Yuji Tasaki
- Department of Materials Engineering, Nagaoka National College of Technology, 888, Nishikatagai, Nagaoka, 940-8532, Niigata, Japan.
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46
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Tekaia F, Latgé JP. Aspergillus fumigatus: saprophyte or pathogen? Curr Opin Microbiol 2005; 8:385-92. [PMID: 16019255 DOI: 10.1016/j.mib.2005.06.017] [Citation(s) in RCA: 261] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2005] [Accepted: 06/22/2005] [Indexed: 11/18/2022]
Abstract
Large-scale genome comparisons have shown that no gene sets are shared exclusively by both Aspergillus fumigatus and any other human pathogen sequenced to date, such as Candida or Cryptococcus species. By contrast, and in agreement with the environmental occurrence of this fungus in decaying vegetation, the enzymatic machinery required by a fungus to colonize plant substrates has been found in the A. fumigatus genome. In addition, the proteome of this fungus contains numerous efflux pumps, including >100 major facilitators that help the fungus to resist either natural aggressive molecules present in the environment or antifungal drugs in humans. Environment sensing, counteracting reactive oxidants, and retrieving essential nutriments from the environment are general metabolic traits that are associated with the growth of the saprotrophic mold A. fumigatus in an unfriendly environment such as its human host.
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Affiliation(s)
- Fredj Tekaia
- Unité de Génétique Moléculaire des Levures, URA 2171 CNRS and UFR 927, Université Pierre et Marie Curie, Institut Pasteur, 25, rue du Dr Roux, 75015 Paris, France
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De Groot PWJ, Ram AF, Klis FM. Features and functions of covalently linked proteins in fungal cell walls. Fungal Genet Biol 2005; 42:657-75. [PMID: 15896991 DOI: 10.1016/j.fgb.2005.04.002] [Citation(s) in RCA: 194] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2005] [Revised: 04/04/2005] [Accepted: 04/05/2005] [Indexed: 10/25/2022]
Abstract
The cell walls of many ascomycetous yeasts consist of an internal network of stress-bearing polysaccharides, which serve as a scaffold for a dense external layer of glycoproteins. GPI-modified proteins are the most abundant cell wall proteins and often display a common organization. Their C-terminus can link them covalently to the polysaccharide network, they possess an internal serine- and threonine-rich spacer domain, and the N-terminal region contains a functional domain. Other proteins bind to the polysaccharide network through a mild-alkali-sensitive linkage. Many cell wall proteins are carbohydrate/glycan-modifying enzymes; adhesion proteins are prominent; proteins involved in iron uptake are present, and also specialized proteins that probably help the fungus to survive in its natural environment. The protein composition of the cell wall depends on environmental conditions and developmental stage. We present evidence that the cell wall of mycelial species of the Ascomycotina is similarly organized and contains glycoproteins with comparable functions.
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Affiliation(s)
- Piet W J De Groot
- Swammerdam Institute for Life Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
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Morelle W, Bernard M, Debeaupuis JP, Buitrago M, Tabouret M, Latgé JP. Galactomannoproteins of Aspergillus fumigatus. EUKARYOTIC CELL 2005; 4:1308-16. [PMID: 16002656 PMCID: PMC1168957 DOI: 10.1128/ec.4.7.1308-1316.2005] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2005] [Accepted: 05/18/2005] [Indexed: 11/20/2022]
Abstract
Galactofuranose-containing molecules have been repeatedly shown to be important antigens among human fungal pathogens, including Aspergillus fumigatus. Immunogenic galactofuran determinants have been poorly characterized chemically, however. We reported here the characterization of two glycoproteins of A. fumigatus with an N-glycan containing galactofuranose. These proteins are a phospholipase C and a phytase. Chemical characterization of the N-glycan indicates that it is a mixture of Hex(5-13)HexNAc(2) oligosaccharides, the major molecular species corresponding to Hex(6-8)HexNAc(2). The N-glycan contained one galactofuranose unit that was in a terminal nonreducing position attached to the 2 position of Man. This single terminal nonreducing galactofuranose is essential for the immunoreactivity of the N-glycans assessed either with a monoclonal antibody that recognizes a tetra-beta-1,5-galactofuran chain of galactomannan or with Aspergillus-infected patient sera.
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Affiliation(s)
- W Morelle
- Unité des Aspergillus, Institut Pasteur, 25, rue du Docteur Roux, 75724 Paris Cedex 15, France
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Rementeria A, López-Molina N, Ludwig A, Vivanco AB, Bikandi J, Pontón J, Garaizar J. Genes and molecules involved in Aspergillus fumigatus virulence. Rev Iberoam Micol 2005; 22:1-23. [PMID: 15813678 DOI: 10.1016/s1130-1406(05)70001-2] [Citation(s) in RCA: 184] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Aspergillus fumigatus causes a wide range of diseases that include mycotoxicosis, allergic reactions and systemic diseases (invasive aspergillosis) with high mortality rates. Pathogenicity depends on immune status of patients and fungal strain. There is no unique essential virulence factor for development of this fungus in the patient and its virulence appears to be under polygenetic control. The group of molecules and genes associated with the virulence of this fungus includes many cell wall components, such as beta-(1-3)-glucan, galactomannan, galactomannanproteins (Afmp1 and Afmp2), and the chitin synthetases (Chs; chsE and chsG), as well as others. Some genes and molecules have been implicated in evasion from the immune response, such as the rodlets layer (rodA/hyp1 gene) and the conidial melanin-DHN (pksP/alb1 gene). The detoxifying systems for Reactive Oxygen Species (ROS) by catalases (Cat1p and Cat2p) and superoxide dismutases (MnSOD and Cu, ZnSOD), had also been pointed out as essential for virulence. In addition, this fungus produces toxins (14 kDa diffusible substance from conidia, fumigaclavin C, aurasperon C, gliotoxin, helvolic acid, fumagilin, Asp-hemolysin, and ribotoxin Asp fI/mitogilin F/restrictocin), allergens (Asp f1 to Asp f23), and enzymatic proteins as alkaline serin proteases (Alp and Alp2), metalloproteases (Mep), aspartic proteases (Pep and Pep2), dipeptidyl-peptidases (DppIV and DppV), phospholipase C and phospholipase B (Plb1 and Plb2). These toxic substances and enzymes seems to be additive and/or synergistic, decreasing the survival rates of the infected animals due to their direct action on cells or supporting microbial invasion during infection. Adaptation ability to different trophic situations is an essential attribute of most pathogens. To maintain its virulence attributes A. fumigatus requires iron obtaining by hydroxamate type siderophores (ornitin monooxigenase/SidA), phosphorous obtaining (fos1, fos2, and fos3), signal transductional falls that regulate morphogenesis and/or usage of nutrients as nitrogen (rasA, rasB, rhbA), mitogen activated kinases (sakA codified MAP-kinase), AMPc-Pka signal transductional route, as well as others. In addition, they seem to be essential in this field the amino acid biosynthesis (cpcA and homoaconitase/lysF), the activation and expression of some genes at 37 degrees C (Hsp1/Asp f12, cgrA), some molecules and genes that maintain cellular viability (smcA, Prp8, anexins), etc. Conversely, knowledge about relationship between pathogen and immune response of the host has been improved, opening new research possibilities. The involvement of non-professional cells (endothelial, and tracheal and alveolar epithelial cells) and professional cells (natural killer or NK, and dendritic cells) in infection has been also observed. Pathogen Associated Molecular Patterns (PAMP) and Patterns Recognizing Receptors (PRR; as Toll like receptors TLR-2 and TLR-4) could influence inflammatory response and dominant cytokine profile, and consequently Th response to infec tion. Superficial components of fungus and host cell surface receptors driving these phenomena are still unknown, although some molecules already associated with its virulence could also be involved. Sequencing of A. fumigatus genome and study of gene expression during their infective process by using DNA microarray and biochips, promises to improve the knowledge of virulence of this fungus.
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Affiliation(s)
- Aitor Rementeria
- Departamento Inmunología, Microbiología y Parasitología, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Spain.
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Latgé JP, Mouyna I, Tekaia F, Beauvais A, Debeaupuis JP, Nierman W. Specific molecular features in the organization and biosynthesis of the cell wall ofAspergillus fumigatus. Med Mycol 2005; 43 Suppl 1:S15-22. [PMID: 16110787 DOI: 10.1080/13693780400029155] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The cell wall of Aspergillus fumigatus is composed of a branched beta1,3 glucan covalently bound to chitin, beta1,3, beta1,4 glucans, and galactomannan, that is embedded in an amorphous cement composed of alpha1,3 glucan, galactomannan and polygalactosamin. The mycelial cell wall of A. fumigatus is very different from the yeast Saccharomyces cerevisiae cell wall, and in particular lacks beta1,6 glucans and proteins covalently bound to cell wall polysaccharides. The differences in cell wall composition between the mould A. fumigatus and the yeast S. cerevisiae are also reflected at the genomic level where unique features have been identified in A. fumigatus. A single gene codes for the glucan synthase catalytic subumit; this finding has lead to the development of a RNAi methodology for the disruption of essential genes in A. fumigatus. In contrast to the glucan synthase, multiple genes have been found in the chitin synthase and the alpha glucan synthase families; in spite of homologous sequences, each gene in each family have very different function. Similarly homologous mannosyltransferase genes are found in yeast and moulds but they lead to the synthesis of very different N-mannan structures. This chemo-genomic comparative analysis has also suggested that GPI-anchored proteins do not have a role of linker in the three dimensional organization of the fungal cell wall.
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Affiliation(s)
- J P Latgé
- Unité des Aspergillus, Institut Pasteur, Paris, France.
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