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Camenzind T, Philipp Grenz K, Lehmann J, Rillig MC. Soil fungal mycelia have unexpectedly flexible stoichiometric C:N and C:P ratios. Ecol Lett 2020; 24:208-218. [DOI: 10.1111/ele.13632] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/21/2020] [Accepted: 09/30/2020] [Indexed: 01/06/2023]
Affiliation(s)
- Tessa Camenzind
- Institute of Biology Freie Universität Berlin Altensteinstr. 6 Berlin14195Germany
- Berlin‐Brandenburg Institute of Advanced Biodiversity Research (BBIB) Berlin14195Germany
| | - Kay Philipp Grenz
- Institute of Biology Freie Universität Berlin Altensteinstr. 6 Berlin14195Germany
| | - Johannes Lehmann
- Soil and Crop Sciences School of Integrative Plant Science Cornell University Ithaca NY14853USA
| | - Matthias C. Rillig
- Institute of Biology Freie Universität Berlin Altensteinstr. 6 Berlin14195Germany
- Berlin‐Brandenburg Institute of Advanced Biodiversity Research (BBIB) Berlin14195Germany
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2
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Zhu Z, Yang M, Bai Y, Ge F, Wang S. Antioxidant-related catalase CTA1 regulates development, aflatoxin biosynthesis, and virulence in pathogenic fungus Aspergillus flavus. Environ Microbiol 2020; 22:2792-2810. [PMID: 32250030 DOI: 10.1111/1462-2920.15011] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/17/2020] [Accepted: 03/31/2020] [Indexed: 11/29/2022]
Abstract
Reactive oxygen species (ROS) induce the synthesis of a myriad of secondary metabolites, including aflatoxins. It raises significant concern as it is a potent environmental contaminant. In Aspergillus flavus., antioxidant enzymes link ROS stress response with coordinated gene regulation of aflatoxin biosynthesis. In this study, we characterized the function of a core component of the antioxidant enzyme catalase (CTA1) of A. flavus. Firstly, we verified the presence of cta1 corresponding protein (CTA1) by Western blot analysis and mass-spectrometry based analysis. Then, the functional study revealed that the growth, sporulation and sclerotia formation significantly increased, while aflatoxins production and virulence were decreased in the cta1 deletion mutant as compared with the WT and complementary strains. Furthermore, the absence of the cta1 gene resulted in a significant rise in the intracellular ROS level, which in turn added to the oxidative stress level of cells. A further quantitative proteomics investigation hinted that in vivo, CTA1 might maintain the ROS level to facilitate the aflatoxin synthesis. All in all, the pleiotropic phenotype of A. flavus CTA1 deletion mutant revealed that the antioxidant system plays a crucial role in fungal development, aflatoxins biosynthesis and virulence.
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Affiliation(s)
- Zhuo Zhu
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Mingkun Yang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Youhuang Bai
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Feng Ge
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Shihua Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
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Emri T, Vékony V, Gila B, Nagy F, Forgács K, Pócsi I. Autolytic hydrolases affect sexual and asexual development of Aspergillus nidulans. Folia Microbiol (Praha) 2018; 63:619-626. [PMID: 29603054 DOI: 10.1007/s12223-018-0601-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 03/21/2018] [Indexed: 11/24/2022]
Abstract
Radial growth, asexual sporulation, and cleistothecia formation as well as extracellular chitinase and proteinase formation of Aspergillus nidulans were monitored in surface cultures in order to study the physiological role of extracellular hydrolase production in carbon-stressed cultures. We set up carbon-stressed and carbon-overfed experimental conditions by varying the starting glucose concentration within the range of 2.5 and 40 g/L. Glucose starvation induced radial growth and hydrolase production and enhanced the maturation of cleistothecia; meanwhile, glucose-rich conditions enhanced mycelial biomass, conidia, and cleistothecia production. Double deletion of chiB and engA (encoding an extracellular endochitinase and a β-1,3-endoglucanase, respectively) decreased conidia production under carbon-stressed conditions, suggesting that these autolytic hydrolases can support conidia formation by releasing nutrients from the cell wall polysaccharides of dead hyphae. Double deletion of prtA and pepJ (both genes encode extracellular proteases) reduced the number of cleistothecia even under carbon-rich conditions except in the presence of casamino acids, which supports the view that sexual development and amino acid metabolism are tightly connected to each other in this fungus.
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Affiliation(s)
- Tamás Emri
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, Debrecen, 4032, Hungary. .,Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, P.O. Box 63, Debrecen, 4010, Hungary.
| | - Viktória Vékony
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, Debrecen, 4032, Hungary
| | - Barnabás Gila
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, Debrecen, 4032, Hungary
| | - Flóra Nagy
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, Debrecen, 4032, Hungary
| | - Katalin Forgács
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, Debrecen, 4032, Hungary
| | - István Pócsi
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, Debrecen, 4032, Hungary
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Kappel L, Gaderer R, Flipphi M, Seidl-Seiboth V. The N-acetylglucosamine catabolic gene cluster in Trichoderma reesei is controlled by the Ndt80-like transcription factor RON1. Mol Microbiol 2016; 99:640-57. [PMID: 26481444 PMCID: PMC4950302 DOI: 10.1111/mmi.13256] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2015] [Indexed: 11/28/2022]
Abstract
Chitin is an important structural constituent of fungal cell walls composed of N-acetylglucosamine (GlcNAc) monosaccharides, but catabolism of GlcNAc has not been studied in filamentous fungi so far. In the yeast Candida albicans, the genes encoding the three enzymes responsible for stepwise conversion of GlcNAc to fructose-6-phosphate are clustered. In this work, we analysed GlcNAc catabolism in ascomycete filamentous fungi and found that the respective genes are also clustered in these fungi. In contrast to C. albicans, the cluster often contains a gene for an Ndt80-like transcription factor, which we named RON1 (regulator of N-acetylglucosamine catabolism 1). Further, a gene for a glycoside hydrolase 3 protein related to bacterial N-acetylglucosaminidases can be found in the GlcNAc gene cluster in filamentous fungi. Functional analysis in Trichoderma reesei showed that the transcription factor RON1 is a key activator of the GlcNAc gene cluster and essential for GlcNAc catabolism. Furthermore, we present an evolutionary analysis of Ndt80-like proteins in Ascomycota. All GlcNAc cluster genes, as well as the GlcNAc transporter gene ngt1, and an additional transcriptional regulator gene, csp2, encoding the homolog of Neurospora crassa CSP2/GRHL, were functionally characterised by gene expression analysis and phenotypic characterisation of knockout strains in T. reesei.
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Affiliation(s)
- Lisa Kappel
- Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, Austria
| | - Romana Gaderer
- Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, Austria
| | - Michel Flipphi
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Verena Seidl-Seiboth
- Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, Austria
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5
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Manzanares-Miralles L, Sarikaya-Bayram Ö, Smith EB, Dolan SK, Bayram Ö, Jones GW, Doyle S. Quantitative proteomics reveals the mechanism and consequence of gliotoxin-mediated dysregulation of the methionine cycle in Aspergillus niger. J Proteomics 2016; 131:149-162. [DOI: 10.1016/j.jprot.2015.10.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/14/2015] [Accepted: 10/18/2015] [Indexed: 12/25/2022]
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Martins I, Hartmann DO, Alves PC, Martins C, Garcia H, Leclercq CC, Ferreira R, He J, Renaut J, Becker JD, Silva Pereira C. Elucidating how the saprophytic fungus Aspergillus nidulans uses the plant polyester suberin as carbon source. BMC Genomics 2014; 15:613. [PMID: 25043916 PMCID: PMC4117967 DOI: 10.1186/1471-2164-15-613] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 07/16/2014] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Lipid polymers in plant cell walls, such as cutin and suberin, build recalcitrant hydrophobic protective barriers. Their degradation is of foremost importance for both plant pathogenic and saprophytic fungi. Regardless of numerous reports on fungal degradation of emulsified fatty acids or cutin, and on fungi-plant interactions, the pathways involved in the degradation and utilisation of suberin remain largely overlooked. As a structural component of the plant cell wall, suberin isolation, in general, uses harsh depolymerisation methods that destroy its macromolecular structure. We recently overcame this limitation isolating suberin macromolecules in a near-native state. RESULTS Suberin macromolecules were used here to analyse the pathways involved in suberin degradation and utilisation by Aspergillus nidulans. Whole-genome profiling data revealed the complex degrading enzymatic machinery used by this saprophytic fungus. Initial suberin modification involved ester hydrolysis and ω-hydroxy fatty acid oxidation that released long chain fatty acids. These fatty acids were processed through peroxisomal β-oxidation, leading to up-regulation of genes encoding the major enzymes of these pathways (e.g. faaB and aoxA). The obtained transcriptome data was further complemented by secretome, microscopic and spectroscopic analyses. CONCLUSIONS Data support that during fungal growth on suberin, cutinase 1 and some lipases (e.g. AN8046) acted as the major suberin degrading enzymes (regulated by FarA and possibly by some unknown regulatory elements). Suberin also induced the onset of sexual development and the boost of secondary metabolism.
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Affiliation(s)
- Isabel Martins
- />Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Diego O Hartmann
- />Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Paula C Alves
- />Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Celso Martins
- />Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
- />Instituto de Biologia Experimental e Tecnológica (iBET), Av. da República, 2781-901 Oeiras, Portugal
| | - Helga Garcia
- />Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Céline C Leclercq
- />Proteomics Platform, Centre de Recherche Public - Gabriel Lippmann, Belvaux, Luxembourg
| | - Rui Ferreira
- />Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Ji He
- />Cancer Genomics Research Laboratory, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, (previously, the Scientific Computing department, Samuel Roberts Noble Foundation, USA, 8717 Grovemont Circle, 20877 Gaithersburg, MD USA
| | - Jenny Renaut
- />Proteomics Platform, Centre de Recherche Public - Gabriel Lippmann, Belvaux, Luxembourg
| | - Jörg D Becker
- />Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal
| | - Cristina Silva Pereira
- />Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
- />Instituto de Biologia Experimental e Tecnológica (iBET), Av. da República, 2781-901 Oeiras, Portugal
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7
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Pusztahelyi T, Pócsi I. Chitinase but N-acetyl-β-D-glucosaminidase production correlates to the biomass decline in Penicillium and Aspergillus species. Acta Microbiol Immunol Hung 2014; 61:131-43. [PMID: 24939682 DOI: 10.1556/amicr.61.2014.2.4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Hydrolytic enzyme production is typical of the autolysis in filamentous fungi; however, less attention has been given to the physiological role of the enzymes. Here, the aim was to investigate the possible relation of the chitinolytic enzymes to the changes in the biomass in some filamentous fungi of high importance for pharmaceutical or food industry. In Penicillium and Aspergillus filamentous fungi, which showed different characteristics in submerged cultures, the growth and biomass decline rates were calculated and correlated to the chitinase and N-acetyl-β-D-glucosaminidase enzyme productions. Correlation was found between the biomass decrease rate and the chitinase level at the stationary growth phase; while chitinase production covariates negatively with N-acetyl-β-D-glucosaminidase activities. The chitinase production and the intensive autolysis hindered the production of N-acetyl-β-D-glucosaminidase and, therefore, could hinder the cell death in the cultures.
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Affiliation(s)
- Tünde Pusztahelyi
- 1 University of Debrecen Central Laboratory, Faculty of Agricultural and Food Sciences and Environmental Management, Centre for Agricultural Sciences Böaszöarményi út 138 H-4032 Debrecen Hungary
| | - István Pócsi
- 2 University of Debrecen Department of Microbial Biotechnology and Cell Biology, Faculty of Science and Technology Egyetem tér 1 H-4032 Debrecen Hungary
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8
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Martins I, Garcia H, Varela A, Núñez O, Planchon S, Galceran MT, Renaut J, Rebelo LPN, Silva Pereira C. Investigating Aspergillus nidulans secretome during colonisation of cork cell walls. J Proteomics 2013; 98:175-88. [PMID: 24316358 DOI: 10.1016/j.jprot.2013.11.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 10/30/2013] [Accepted: 11/23/2013] [Indexed: 11/19/2022]
Abstract
UNLABELLED Cork, the outer bark of Quercus suber, shows a unique compositional structure, a set of remarkable properties, including high recalcitrance. Cork colonisation by Ascomycota remains largely overlooked. Herein, Aspergillus nidulans secretome on cork was analysed (2DE). Proteomic data were further complemented by microscopic (SEM) and spectroscopic (ATR-FTIR) evaluation of the colonised substrate and by targeted analysis of lignin degradation compounds (UPLC-HRMS). Data showed that the fungus formed an intricate network of hyphae around the cork cell walls, which enabled polysaccharides and lignin superficial degradation, but probably not of suberin. The degradation of polysaccharides was suggested by the identification of few polysaccharide degrading enzymes (β-glucosidases and endo-1,5-α-l-arabinosidase). Lignin degradation, which likely evolved throughout a Fenton-like mechanism relying on the activity of alcohol oxidases, was supported by the identification of small aromatic compounds (e.g. cinnamic acid and veratrylaldehyde) and of several putative high molecular weight lignin degradation products. In addition, cork recalcitrance was corroborated by the identification of several protein species which are associated with autolysis. Finally, stringent comparative proteomics revealed that A. nidulans colonisation of cork and wood share a common set of enzymatic mechanisms. However the higher polysaccharide accessibility in cork might explain the increase of β-glucosidase in cork secretome. BIOLOGICAL SIGNIFICANCE Cork degradation by fungi remains largely overlook. Herein we aimed at understanding how A. nidulans colonise cork cell walls and how this relates to wood colonisation. To address this, the protein species consistently present in the secretome were analysed, as well as major alterations occurring in the substrate, including lignin degradation compounds being released. The obtained data demonstrate that this fungus has superficially attacked the cork cell walls apparently by using both enzymatic and Fenton-like reactions. Only a few polysaccharide degrading enzymes could be detected in the secretome which was dominated by protein species associated with autolysis. Lignin degradation was corroborated by the identification of some degradation products, but the suberin barrier in the cell wall remained virtually intact. Comparative proteomics revealed that cork and wood colonisation share a common set of enzymatic mechanisms.
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Affiliation(s)
- Isabel Martins
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal; Instituto de Biologia Experimental e Tecnológica (IBET), Apartado 12, 2781-901 Oeiras, Portugal
| | - Helga Garcia
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Adélia Varela
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal; Instituto Nacional de Investigação Agrária e Veterinária, (INIAV), Av. da República, Quinta do Marquês, 2784-505 Oeiras, Portugal
| | - Oscar Núñez
- Department of Analytical Chemistry, University of Barcelona, Diagonal 645, E-08028 Barcelona, Spain
| | - Sébastien Planchon
- Proteomics Platform, Centre de Recherche Public -Gabriel Lippmann, Belvaux, Luxembourg
| | - Maria Teresa Galceran
- Department of Analytical Chemistry, University of Barcelona, Diagonal 645, E-08028 Barcelona, Spain
| | - Jenny Renaut
- Proteomics Platform, Centre de Recherche Public -Gabriel Lippmann, Belvaux, Luxembourg
| | - Luís P N Rebelo
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Cristina Silva Pereira
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal; Instituto de Biologia Experimental e Tecnológica (IBET), Apartado 12, 2781-901 Oeiras, Portugal.
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9
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Kang JY, Chun J, Jun SC, Han DM, Chae KS, Jahng KY. The MpkB MAP kinase plays a role in autolysis and conidiation of Aspergillus nidulans. Fungal Genet Biol 2013; 61:42-9. [DOI: 10.1016/j.fgb.2013.09.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 09/23/2013] [Accepted: 09/26/2013] [Indexed: 12/23/2022]
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10
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Martins I, Hartmann DO, Alves PC, Planchon S, Renaut J, Leitão MC, Rebelo LP, Silva Pereira C. Proteomic alterations induced by ionic liquids in Aspergillus nidulans and Neurospora crassa. J Proteomics 2013; 94:262-78. [DOI: 10.1016/j.jprot.2013.09.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Revised: 09/13/2013] [Accepted: 09/27/2013] [Indexed: 02/03/2023]
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11
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van Munster JM, Nitsche BM, Krijgsheld P, van Wijk A, Dijkhuizen L, Wösten HA, Ram AF, van der Maarel MJEC. Chitinases CtcB and CfcI modify the cell wall in sporulating aerial mycelium of Aspergillus niger. Microbiology (Reading) 2013; 159:1853-1867. [DOI: 10.1099/mic.0.067967-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Jolanda M. van Munster
- Microbial Physiology Research Group, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Benjamin M. Nitsche
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Kluyver Centre for Genomics of Industrial Fermentation, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Pauline Krijgsheld
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentation, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Alle van Wijk
- Aquatic Biotechnology and Bioproduct Engineering Department, Institute for Technology and Management (ITM), University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Lubbert Dijkhuizen
- Microbial Physiology Research Group, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Han A. Wösten
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentation, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Arthur F. Ram
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Kluyver Centre for Genomics of Industrial Fermentation, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Marc J. E. C. van der Maarel
- Aquatic Biotechnology and Bioproduct Engineering Department, Institute for Technology and Management (ITM), University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Microbial Physiology Research Group, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
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12
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Yang J, Yu Y, Li J, Zhu W, Geng Z, Jiang D, Wang Y, Zhang KQ. Characterization and functional analyses of the chitinase-encoding genes in the nematode-trapping fungus Arthrobotrys oligospora. Arch Microbiol 2013; 195:453-62. [PMID: 23661195 DOI: 10.1007/s00203-013-0894-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 04/08/2013] [Accepted: 04/11/2013] [Indexed: 01/17/2023]
Abstract
Nematode-trapping fungi can secrete many extracellular hydrolytic enzymes such as serine proteases and chitinases to digest and penetrate nematode/egg-cuticles. However, little is known about the structure and function of chitinases in these fungi. In this study, 16 ORFs encoding putative chitinases, which all belong to glycoside hydrolase (GH) family 18, were identified from the Arthrobotrys oligospora genome. Bioinformatics analyses showed that these 16 putative chitinases differ in their functional domains, molecular weights and pI. Phylogenetic analysis grouped these A. oligospora chitinases into four clades: clades I, II, III and IV, respectively, including an A. oligospora-specific subclade (Clade IV-B) that contained high-molecular weight chitinases (≥100 kDa). Transcriptional analysis of A. oligospora chitinases suggested that the expression of most chitinases was repressed by carbon starvation, and all chitinases were up-regulated under nitrogen starvation. However, chitinase AO-190 was up-regulated under carbon and/or nitrogen starvation. Moreover, several chitinases (such as AO-59, AO-190 and AO-801) were up-regulated in the presence of chitinous substrates or a plant pathogenic fungus, indicating that they could play a role in biocontrol applications of A. oligospora. Our results provided a basis for further understanding the functions, diversities and evolutionary relationships between chitinase genes in nematode-trapping fungi.
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Affiliation(s)
- Jinkui Yang
- Laboratory for Conservation and Utilization of Bio-Resources, and Key Laboratory of Microbial Diversity in Southwest China, Ministry of Education, Yunnan University, Kunming 650091, People's Republic of China.
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13
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Kovács Z, Szarka M, Kovács S, Boczonádi I, Emri T, Abe K, Pócsi I, Pusztahelyi T. Effect of cell wall integrity stress and RlmA transcription factor on asexual development and autolysis in Aspergillus nidulans. Fungal Genet Biol 2013; 54:1-14. [PMID: 23485399 DOI: 10.1016/j.fgb.2013.02.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Revised: 02/13/2013] [Accepted: 02/14/2013] [Indexed: 11/24/2022]
Abstract
The cell wall integrity (CWI) signaling pathway is responsible for cell wall remodeling and reinforcement upon cell wall stress, which is proposed to be universal in fungal cultures. In Aspergillus nidulans, both the deletion of rlmA encoding the RlmA transcription factor in CWI signaling and low concentrations of the cell wall polymer intercalating agent Congo Red caused significant physiological changes. The gene deletion mutant ΔrlmA strain showed decreased CWI and oxidative stress resistances, which indicated the connection between the CWI pathway and the oxidative stress response system. The Congo Red stress resulted in alterations in the cell wall polymer composition in submerged cultures due to the induction of the biosynthesis of the alkali soluble fraction as well as the hydrolysis of cell wall biopolymers. Both RlmA and RlmA-independent factors induced by Congo Red stress regulated the expression of glucanase (ANID_00245, engA) and chitinase (chiB, chiA) genes, which promoted the autolysis of the cultures and also modulated the pellet sizes. CWI stress and rlmA deletion affected the expression of brlA encoding the early conidiophore development regulator transcription factor BrlA and, as a consequence, the formation of conidiophores was significantly changed in submerged cultures. Interestingly, the number of conidiospores increased in surface cultures of the ΔrlmA strain. The in silico analysis of genes putatively regulated by RlmA and the CWI transcription factors AnSwi4/AnSwi6 in the SBF complex revealed only a few jointly regulated genes, including ugmA and srrA coding for UgmA UDP-galactopyranose mutase and SrrA stress response regulator, respectively.
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Affiliation(s)
- Zsuzsanna Kovács
- Department of Microbial Biotechnology and Cell Biology, Faculty of Science and Technology, University of Debrecen, H-4010 Debrecen, Hungary
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14
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Nitsche BM, Jørgensen TR, Akeroyd M, Meyer V, Ram AFJ. The carbon starvation response of Aspergillus niger during submerged cultivation: insights from the transcriptome and secretome. BMC Genomics 2012; 13:380. [PMID: 22873931 PMCID: PMC3527191 DOI: 10.1186/1471-2164-13-380] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 07/26/2012] [Indexed: 01/13/2023] Open
Abstract
Background Filamentous fungi are confronted with changes and limitations of their carbon source during growth in their natural habitats and during industrial applications. To survive life-threatening starvation conditions, carbon from endogenous resources becomes mobilized to fuel maintenance and self-propagation. Key to understand the underlying cellular processes is the system-wide analysis of fungal starvation responses in a temporal and spatial resolution. The knowledge deduced is important for the development of optimized industrial production processes. Results This study describes the physiological, morphological and genome-wide transcriptional changes caused by prolonged carbon starvation during submerged batch cultivation of the filamentous fungus Aspergillus niger. Bioreactor cultivation supported highly reproducible growth conditions and monitoring of physiological parameters. Changes in hyphal growth and morphology were analyzed at distinct cultivation phases using automated image analysis. The Affymetrix GeneChip platform was used to establish genome-wide transcriptional profiles for three selected time points during prolonged carbon starvation. Compared to the exponential growth transcriptome, about 50% (7,292) of all genes displayed differential gene expression during at least one of the starvation time points. Enrichment analysis of Gene Ontology, Pfam domain and KEGG pathway annotations uncovered autophagy and asexual reproduction as major global transcriptional trends. Induced transcription of genes encoding hydrolytic enzymes was accompanied by increased secretion of hydrolases including chitinases, glucanases, proteases and phospholipases as identified by mass spectrometry. Conclusions This study is the first system-wide analysis of the carbon starvation response in a filamentous fungus. Morphological, transcriptomic and secretomic analyses identified key events important for fungal survival and their chronology. The dataset obtained forms a comprehensive framework for further elucidation of the interrelation and interplay of the individual cellular events involved.
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Affiliation(s)
- Benjamin M Nitsche
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands.
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Tóth V, Nagy CT, Pócsi I, Emri T. The echinocandin B producer fungus Aspergillus nidulans var. roseus ATCC 58397 does not possess innate resistance against its lipopeptide antimycotic. Appl Microbiol Biotechnol 2012; 95:113-22. [PMID: 22555909 DOI: 10.1007/s00253-012-4027-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 03/12/2012] [Accepted: 03/13/2012] [Indexed: 12/01/2022]
Abstract
Aspergillus nidulans var. roseus ATCC 58397 is an echinocandin B (ECB) producer ascomycete with great industrial importance. As demonstrated by ECB/caspofungin sensitivity assays, A. nidulans var. roseus does not possess any inherent resistance to echinocandins, and its tolerance to these lipopeptide antimycotics are even lower than those of the non-producer A. nidulans FGSC A4 strain. Under ECB producing conditions or ECB exposures, A. nidulans var. roseus induced its ECB tolerance via up-regulating elements of the chitin biosynthetic machinery and, hence, through changing dynamically the composition of its own cell wall. Importantly, although the specific β-1,3-glucan synthase activity was elevated, these changes reduced the β-glucan content of hyphae considerably, but the expression of fksA, encoding the catalytic subunit of β-1,3-glucan synthase, the putative target of echinocandins in the aspergilli, was not affected. These data suggest that compensatory chitin biosynthesis is the centerpiece of the induced ECB tolerance of A. nidulans var. roseus. It is important to note that the induced tolerance to ECB (although resulted in paradoxical growth at higher ECB concentrations) was accompanied with reduced growth rate and, under certain conditions, even sensitized the fungus to other stress-generating agents like SDS. We hypothesize that although ECB-resistant mutants may arise in vivo in A. nidulans var. roseus cultures, their widespread propagation is severely restricted by the disadvantageous physiological effects of such mutations.
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Affiliation(s)
- Viktória Tóth
- Department of Microbial Biotechnology and Cell Biology, Faculty of Science and Technology, University of Debrecen, 4032 Debrecen, Hungary
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Kamerewerd J, Zadra I, Kürnsteiner H, Kück U. PcchiB1, encoding a class V chitinase, is affected by PcVelA and PcLaeA, and is responsible for cell wall integrity in Penicillium chrysogenum. MICROBIOLOGY-SGM 2011; 157:3036-3048. [PMID: 21816879 DOI: 10.1099/mic.0.051896-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Penicillin production in Penicillium chrysogenum is controlled by PcVelA and PcLaeA, two components of the regulatory velvet-like complex. Comparative microarray analysis with mutants lacking PcVelA or PcLaeA revealed a set of 62 common genes affected by the loss of both components. A downregulated gene in both knockout strains is PcchiB1, potentially encoding a class V chitinase. Under nutrient-depleted conditions, transcript levels of PcchiB1 are strongly upregulated, and the gene product contributes to more than 50 % of extracellular chitinase activity. Functional characterization by generating PcchiB1-disruption strains revealed that PcChiB1 is responsible for cell wall integrity and pellet formation in P. chrysogenum. Further, fluorescence microscopy with a DsRed-labelled chitinase suggests a cell wall association of the protein. An unexpected phenotype occurred when knockout strains were grown on media containing N-acetylglucosamine as the sole C and N source, where, in contrast to the recipient, a penicillin producer strain, the mutants and an ancestral strain show distinct mycelial growth. We discuss the relevance of this class V chitinase for morphology in an industrially important fungus.
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Affiliation(s)
- Jens Kamerewerd
- Christian Doppler Laboratory for 'Fungal Biotechnology', Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Ivo Zadra
- Anti Infectives Microbiology, Sandoz GmbH, Biochemiestraße 10, 6250 Kundl, Austria
| | - Hubert Kürnsteiner
- Anti Infectives Microbiology, Sandoz GmbH, Biochemiestraße 10, 6250 Kundl, Austria
| | - Ulrich Kück
- Christian Doppler Laboratory for 'Fungal Biotechnology', Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany
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Szilágyi M, Kwon NJ, Dorogi C, Pócsi I, Yu JH, Emri T. The extracellular β-1,3-endoglucanase EngA is involved in autolysis of Aspergillus nidulans. J Appl Microbiol 2010; 109:1498-508. [PMID: 20602653 DOI: 10.1111/j.1365-2672.2010.04782.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS To elucidate the roles of the β-1,3-endoglucanase EngA in autolysis of the filamentous fungus Aspergillus nidulans and to identify the common regulatory elements of autolytic hydrolases. METHODS AND RESULTS A β-1,3-endoglucanase was purified from carbon-starving cultures of A. nidulans. This enzyme is found to be encoded by the engA gene (locus ID: AN0472.3). Functional and gene-expression studies demonstrated that EngA is involved in the autolytic cell wall degradation resulting from carbon starvation of the fungus. Moreover, regulation of engA is found to be dependent on the FluG/BrlA asexual sporulation signalling pathway in submerged culture. The deletion of either engA or chiB (encoding an endochitinase) caused highly reduced production of hydrolases in general. CONCLUSIONS The β-1,3-endoglucanase EngA plays a pivotal role in fungal autolysis, and activities of both EngA and ChiB are necessary to orchestrate the expression of autolytic hydrolases. The production of cell wall-degrading enzymes was coordinately controlled in a highly sophisticated and complex manner. SIGNIFICANCE AND IMPACT OF THE STUDY No information was available on the autolytic glucanase(s) of the euascomycete A. nidulans. This study demonstrates that EngA is a key element in fungal autolysis, and normal activities of both EngA and ChiB are crucial for balanced production of hydrolases.
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Affiliation(s)
- M Szilágyi
- Department of Microbial Biotechnology and Cell Biology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
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18
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AtfA bZIP-type transcription factor regulates oxidative and osmotic stress responses in Aspergillus nidulans. Mol Genet Genomics 2010; 283:289-303. [PMID: 20131067 DOI: 10.1007/s00438-010-0513-z] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Accepted: 01/18/2010] [Indexed: 12/18/2022]
Abstract
The aim of the study was to demonstrate that the bZIP-type transcription factor AtfA regulates different types of stress responses in Aspergillus nidulans similarly to Atf1, the orthologous 'all-purpose' transcription factor of Schizosaccharomyces pombe. Heterologous expression of atfA in a S. pombe Deltaatf1 mutant restored the osmotic stress tolerance of fission yeast in surface cultures to the same level as recorded in complementation studies with the atf1 gene, and a partial complementation of the osmotic and oxidative-stress-sensitive phenotypes was also achieved in submerged cultures. AtfA is therefore a true functional ortholog of fission yeast's Atf1. As demonstrated by RT-PCR experiments, elements of both oxidative (e.g. catalase B) and osmotic (e.g. glycerol-3-phosphate dehydrogenase B) stress defense systems were transcriptionally regulated by AtfA in a stress-type-specific manner. Deletion of atfA resulted in oxidative-stress-sensitive phenotypes while the high-osmolarity stress sensitivity of the fungus was not affected significantly. In A. nidulans, the glutathione/glutathione disulfide redox status of the cells as well as apoptotic cell death and autolysis seemed to be controlled by regulatory elements other than AtfA. In conclusion, the orchestrations of stress responses in the aspergilli and in fission yeast share several common features, but further studies are needed to answer the important question of whether a fission yeast-like core environmental stress response also operates in the euascomycete genus Aspergillus.
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Chitinases are essential for sexual development but not vegetative growth in Cryptococcus neoformans. EUKARYOTIC CELL 2009; 8:1692-705. [PMID: 19734369 DOI: 10.1128/ec.00227-09] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Cryptococcus neoformans is an opportunistic pathogen that mainly infects immunocompromised individuals. The fungal cell wall of C. neoformans is an excellent target for antifungal therapies since it is an essential organelle that provides cell structure and integrity. Importantly, it is needed for localization or attachment of known virulence factors, including melanin, phospholipase, and the polysaccharide capsule. The polysaccharide fraction of the cryptococcal cell wall is a complex structure composed of chitin, chitosan, and glucans. Chitin is an indispensable component of many fungal cell walls that contributes significantly to cell wall strength and integrity. Fungal cell walls are very dynamic, constantly changing during cell division and morphogenesis. Hydrolytic enzymes, such as chitinases, have been implicated in the maintenance of cell wall plasticity and separation of the mother and daughter cells at the bud neck during vegetative growth in yeast. In C. neoformans we identified four predicted endochitinases, CHI2, CHI21, CHI22, and CHI4, and a predicted exochitinase, hexosaminidase, HEX1. Enzymatic analysis indicated that Chi2, Chi22, and Hex1 actively degraded chitinoligomeric substrates. Chi2 and Hex1 activity was associated mostly with the cellular fraction, and Chi22 activity was more prominent in the supernatant. The enzymatic activity of Hex1 increased when grown in media containing only N-acetylglucosamine as a carbon source, suggesting that its activity may be inducible by chitin degradation products. Using a quadruple endochitinase deletion strain, we determined that the endochitinases do not affect the growth or morphology of C. neoformans during asexual reproduction. However, mating assays indicated that Chi2, Chi21, and Chi4 are each involved in sexual reproduction. In summary, the endochitinases were found to be dispensable for routine vegetative growth but not sexual reproduction.
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López-Mondéjar R, Catalano V, Kubicek CP, Seidl V. The beta-N-acetylglucosaminidases NAG1 and NAG2 are essential for growth of Trichoderma atroviride on chitin. FEBS J 2009; 276:5137-48. [PMID: 19674110 DOI: 10.1111/j.1742-4658.2009.07211.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The chitinolytic enzyme machinery of fungi consists of chitinases and beta-N-acetylglucosaminidases. These enzymes are important during the fungal life cycle for degradation of exogenous chitin, which is the second most abundant biopolymer, as well as fungal cell-wall remodelling. In addition, involvement of chitinolytic enzymes in the lysis of the host cell wall in mycoparasitic Trichoderma spp. has been reported. In view of the fact that fungi have on average 15-20 chitinases, but only two beta-N-acetylglucosaminidases, the question arises how important the latter enzymes actually are for various aspects of chitin degradation. In this study, the role of two beta-N-acetylglucosaminidases, NAG1 and NAG2, was analysed in the mycoparasitic fungus Trichoderma atroviride. No beta-N-acetylglucosaminidase activity was detected in T. atrovirideDeltanag1Deltanag2 strains, suggesting that NAG1 and NAG2 are the only enzymes in T. atroviride that possess this activity. Deltanag1Deltanag2 strains were not able to grow on chitin and chitobiose, but the presence of either NAG1 or NAG2 was sufficient to restore growth on chitinous carbon sources in solid media. Our results demonstrated that T. atroviride cannot metabolize chitobiose but only the monomer N-acetylglucosamine, and that N-acetylglucosaminidases are therefore essential for the use of chitin as a nutrient source. NAG1 is predominantly secreted into the medium, whereas NAG2 mainly remains attached to the cell wall. No physiological changes or reduction of the mycoparasitic potential of T. atroviride was detected in the double knockout strains, suggesting that the use of chitin as carbon source is only of minor importance for these processes.
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Affiliation(s)
- Rubén López-Mondéjar
- Research Area Gene Technology and Applied Biochemistry, Institute of Chemical Engineering, Vienna University of Technology, Austria
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21
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Pócsi I, Leiter E, Kwon NJ, Shin KS, Kwon GS, Pusztahelyi T, Emri T, Abuknesha RA, Price RG, Yu JH. Asexual sporulation signalling regulates autolysis of Aspergillus nidulans via modulating the chitinase ChiB production. J Appl Microbiol 2009; 107:514-23. [PMID: 19486415 DOI: 10.1111/j.1365-2672.2009.04237.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS Elucidation of the regulation of ChiB production in Aspergillus nidulans. METHODS AND RESULTS Mutational inactivation of the A. nidulans chiB gene resulted in a nonautolytic phenotype. To better understand the mechanisms controlling both developmental progression and fungal autolysis, we examined a range of autolysis-associated parameters in A. nidulans developmental and/or autolytic mutants. Investigation of disorganization of mycelial pellets, loss of biomass, extra-/intracellular chitinase activities, ChiB production and chiB mRNA levels in various cultures revealed that, in submerged cultures, initialization of autolysis and stationary phase-induced ChiB production are intimately coupled, and that both processes are controlled by the FluG-BrlA asexual sporulation regulatory pathway. ChiB production does not affect the progression of apoptotic cell death in the aging A. nidulans cultures. CONCLUSIONS The endochitinase ChiB plays an important role in autolysis of A. nidulans, and its production is initiated by FluG-BrlA signalling. Despite the fact that apoptosis is an inseparable part of fungal autolysis, its regulation is independent to FluG-initiated sporulation signalling. SIGNIFICANCE AND IMPACT OF THE STUDY Deletion of chiB and fluG homologues in industrial filamentous fungal strains may stabilize the hyphal structures in the autolytic phase of growth and limit the release of autolytic hydrolases into the culture medium.
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Affiliation(s)
- I Pócsi
- Department of Microbial Biotechnology and Cell Biology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary.
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PepJ is a new extracellular proteinase of Aspergillus nidulans. Folia Microbiol (Praha) 2009; 54:105-9. [DOI: 10.1007/s12223-009-0015-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2008] [Revised: 01/06/2009] [Indexed: 10/20/2022]
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23
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Differential roles of the ChiB chitinase in autolysis and cell death of Aspergillus nidulans. EUKARYOTIC CELL 2009; 8:738-46. [PMID: 19286987 DOI: 10.1128/ec.00368-08] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Autolysis is a natural event that occurs in most filamentous fungi. Such self-degradation of fungal cells becomes a predominant phenomenon in the absence of the regulator of G protein signaling FlbA in Aspergillus nidulans. Among a number of potential hydrolytic enzymes in the A. nidulans genome, the secreted endochitinase ChiB was shown to play a major role in autolysis. In this report, we investigate the roles of ChiB in fungal autolysis and cell death processes through genetic, biochemical, and cellular analyses using a set of critical mutants. Determination of mycelial mass revealed that, while the flbA deletion (DeltaflbA) mutant autolyzed completely after a 3-day incubation, the DeltaflbA DeltachiB double mutant escaped from hyphal disintegration. These results indicate that ChiB is necessary for the DeltaflbA-induced autolysis. However, importantly, both DeltaflbA and DeltaflbA DeltachiB strains displayed dramatically reduced cell viability compared to the wild type. These imply that ChiB is dispensable for cell death and that autolysis and cell death are separate processes. Liquid chromatography-tandem mass spectrometry analyses of the proteins that accumulate at high levels in the DeltaflbA and DeltaflbA DeltachiB mutants identify chitinase (ChiB), dipeptidyl peptidase V (DppV), O-glycosyl compound hydrolase, beta-N-acetylhexosaminidase (NagA), and myo-inositol-1-phosphate synthase (InoB). Functional characterization of these four genes reveals that the deletion of nagA results in reduced cell death. A working model bridging G protein signaling and players in autolysis/cell death is proposed.
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Erdei E, Pusztahelyi T, Miskei M, Barna T, Pócsi I. Characterization and heterologous expression of an age-dependent fungal/bacterial type chitinase of Aspergillus nidulans. Acta Microbiol Immunol Hung 2008; 55:351-61. [PMID: 18800599 DOI: 10.1556/amicr.55.2008.3.6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Under carbon starvation, Aspergillus nidulans produced a fungal/bacterial type chitinase, ChiB. The chiB gene was cloned and subcloned into pJC40 expression vector containing a 10XHis fusion tag, and the ChiB protein was expressed heterologously in Escherichia coli. Recombinant and native ChiB enzymes shared the same optimal pH ranges and showed similar substrate specificities with endo-acting cleavage patterns.
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Affiliation(s)
- Eva Erdei
- Department of Microbial Biotechnology and Cell Biology, Faculty of Science and Technology, University of Debrecen, H-4010 Debrecen, Hungary
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25
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Fliegerová K, Hoffmann K, Mrázek J, Voigt K. The design of oligonucleotide primers for the universal amplification of the N-acetylglucosaminidase gene (nag1) in Chytridiomycetes with emphasis on the anaerobic Neocallimastigales. Folia Microbiol (Praha) 2008; 53:209-13. [PMID: 18661293 DOI: 10.1007/s12223-008-0027-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Revised: 01/17/2008] [Indexed: 11/29/2022]
Abstract
The common feature of all chytridiomycetous fungi, aerobic as well as anaerobic, is an abundance of chitin in their cell wall. The genes coding for chitinases have therefore been widely used as phylogenetic markers in ascomycetes. As their utility for Chytridiomycetes has not been determined we chose the gene encoding an enzyme involved in chitin degradation and energy metabolism, the beta-(1,4)-N-acetylglucosaminidase (nag1). Primer pair Nag-forward and Nag-reverse was used to create PCR product from 5 strains of anaerobic and 7 strains of aerobic chytrids. However, Blast search of sequenced amplicons showed that these primers are specific only for fungus Emericella nidulans. Amino acid alignment of Nag1 proteins of fungal, protozoal and bacterial origin available in GenBank database was therefore performed. Five amino acid regions were found to be conserved enough to serve as a suitable domain for the design of a set of primers for the universal amplification of the nag1 gene in the Neocallimastigales fungi.
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Affiliation(s)
- K Fliegerová
- Institute of Animal Physiology and Genetics, v.v.i., Academy of Sciences of the Czech Republic, Prague, Czechia.
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Simůnek J, Tishchenko G, Koppová I. Chitinolytic activities of Clostridium sp. JM2 isolated from stool of human administered per orally by chitosan. Folia Microbiol (Praha) 2008; 53:249-54. [PMID: 18661303 DOI: 10.1007/s12223-008-0037-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Revised: 01/17/2008] [Indexed: 11/28/2022]
Abstract
The novel chitinolytic bacterium Clostridium beijerinckii strain JM2 was isolated from the stool of healthy volunteers supplied daily per orally with 3 g of chitosan. The bacterium grown on colloidal chitin produced a complete array of chitinolytic enzymes. Significant activities of endochitinase, exochitinase and chitosanase were excreted into the medium (301, 282 and 268 nkat/microg protein, respectively). The high cellular activity of N-acetyl-beta-glucosaminidase (NAGase) and chitosanase were detected (732.4 and 154 nkat/microg protein, respectively). NAGase activity represented the main activity associated with the cellular fraction. The activities of both enzymes tested increased from 20 to 50 degrees C; the optimum reaction temperature estimated being 50 degrees C. Endochitinase as well as NAGase showed an activity in the pH interval of 4.0-8.0; the optimum pH values were 6.5 and 6.0, respectively. The extracellular endochitinase complex consisted of six isoenzymes with molar mass of 32-76 kDa; in the cellular fraction five bands with molar mass of 45-86 kDa were detected. Exochitinase activity was demonstrated in the form of three bands (with molar mass of 30-57 kDa), NAGase activity displayed one band of 45 kDa.
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Affiliation(s)
- J Simůnek
- Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, 142 20 Prague, Czechia.
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Yamazaki H, Tanaka A, Kaneko JI, Ohta A, Horiuchi H. Aspergillus nidulans ChiA is a glycosylphosphatidylinositol (GPI)-anchored chitinase specifically localized at polarized growth sites. Fungal Genet Biol 2008; 45:963-72. [PMID: 18420434 DOI: 10.1016/j.fgb.2008.02.008] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Revised: 02/25/2008] [Accepted: 02/25/2008] [Indexed: 11/26/2022]
Abstract
It is believed that chitinases play important physiological roles in filamentous fungi since chitin is one of the major cell wall components in these organisms. In this paper we investigated a chitinase gene, chiA, of Aspergillus nidulans and found that the gene product of chiA consists of a signal sequence, a region including chitinase consensus motifs, a Ser/Thr/Pro-rich region and a glycosylphosphatidylinositol (GPI)-anchor attachment motif. Phosphatidylinositol-specific phospholipase C treatment of the fusion protein of ChiA and enhanced green fluorescent protein (EGFP)-ChiA-EGFP-caused a change in its hydrophobicity, indicating that ChiA is a GPI-anchored protein. ChiA-EGFP localized at the germ tubes of conidia, at hyphal branching sites and hyphal tips. chiA expression was specifically high during conidia germination and in the marginal growth regions of colonies. These results suggest that ChiA functions as a GPI-anchored chitinase at the sites where cell wall remodeling and/or cell wall maturation actively take place.
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Affiliation(s)
- Harutake Yamazaki
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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Regulation of autolysis in Aspergillus nidulans. Appl Biochem Biotechnol 2008; 151:211-20. [PMID: 18975147 DOI: 10.1007/s12010-008-8174-7] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Accepted: 02/05/2008] [Indexed: 10/22/2022]
Abstract
In terms of cell physiology, autolysis is the centerpiece of carbon-starving fungal cultures. In the filamentous fungus model organism Aspergillus nidulans, the last step of carbon-starvation-triggered autolysis was the degradation of the cell wall of empty hyphae, and this process was independent of concomitantly progressing cell death at the level of regulation. Autolysis-related proteinase and chitinase activities were induced via FluG signaling, which initiates sporulation and inhibits vegetative growth in surface cultures of A. nidulans. Extracellular hydrolase production was also subjected to carbon repression, which was only partly dependent on CreA, the main carbon catabolite repressor in this fungus. These data support the view that one of the main functions of autolysis is supplying nutrients for sporulation, when no other sources of nutrients are available. The divergent regulation of cell death and cell wall degradation provides the fungus with the option to keep dead hyphae intact to help surviving cells to absorb biomaterials from dead neighboring cells before these are released into the extracellular space. The industrial significance of these observations is also discussed in this paper.
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Seidl V. Chitinases of filamentous fungi: a large group of diverse proteins with multiple physiological functions. FUNGAL BIOL REV 2008. [DOI: 10.1016/j.fbr.2008.03.002] [Citation(s) in RCA: 184] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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