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Hoskisson PA, Barona-Gómez F, Rozen DE. Phenotypic heterogeneity in Streptomyces colonies. Curr Opin Microbiol 2024; 78:102448. [PMID: 38447313 DOI: 10.1016/j.mib.2024.102448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/30/2024] [Accepted: 02/06/2024] [Indexed: 03/08/2024]
Abstract
Streptomyces are a large genus of multicellular bacteria best known for their prolific production of bioactive natural products. In addition, they play key roles in the mineralisation of insoluble resources, such as chitin and cellulose. Because of their multicellular mode of growth, colonies of interconnected hyphae extend over a large area that may experience different conditions in different parts of the colony. Here, we argue that within-colony phenotypic heterogeneity can allow colonies to simultaneously respond to divergent inputs from resources or competitors that are spatially and temporally dynamic. We discuss causal drivers of heterogeneity, including competitors, precursor availability, metabolic diversity and division of labour, that facilitate divergent phenotypes within Streptomyces colonies. We discuss the adaptive causes and consequences of within-colony heterogeneity, highlight current knowledge (gaps) and outline key questions for future studies.
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Affiliation(s)
- Paul A Hoskisson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK
| | | | - Daniel E Rozen
- Institute of Biology, Leiden University, Sylviusweg 72, Leiden, The Netherlands.
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2
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Adamatzky A, Ayres P, Beasley AE, Chiolerio A, Dehshibi MM, Gandia A, Albergati E, Mayne R, Nikolaidou A, Roberts N, Tegelaar M, Tsompanas MA, Phillips N, Wösten HAB. Fungal electronics. Biosystems 2021; 212:104588. [PMID: 34979157 DOI: 10.1016/j.biosystems.2021.104588] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 11/30/2021] [Accepted: 12/03/2021] [Indexed: 12/31/2022]
Abstract
Fungal electronics is a family of living electronic devices made of mycelium bound composites or pure mycelium. Fungal electronic devices are capable of changing their impedance and generating spikes of electrical potential in response to external control parameters. Fungal electronics can be embedded into fungal materials and wearables or used as stand alone sensing and computing devices.
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Affiliation(s)
| | - Phil Ayres
- The Centre for Information Technology and Architecture, Royal Danish Academy, Copenhagen, Denmark
| | | | - Alessandro Chiolerio
- Unconventional Computing Laboratory, UWE, Bristol, UK; Center for Bioinspired Soft Robotics, Istituto Italiano di Tecnologia, Via Morego 30, 10163 Genova, Italy
| | - Mohammad M Dehshibi
- Department of Computer Science, Multimedia and Telecommunications, Universitat Oberta de Catalunya, Barcelona, Spain
| | - Antoni Gandia
- Institute for Plant Molecular and Cell Biology, CSIC-UPV, Valencia, Spain
| | - Elena Albergati
- Department of Design, Politecnico di Milano, Milan, Italy; MOGU S.r.l., Inarzo, Italy
| | - Richard Mayne
- Unconventional Computing Laboratory, UWE, Bristol, UK
| | | | - Nic Roberts
- Unconventional Computing Laboratory, UWE, Bristol, UK
| | - Martin Tegelaar
- Microbiology, Department of Biology, University of Utrecht, Utrecht, The Netherlands
| | | | - Neil Phillips
- Unconventional Computing Laboratory, UWE, Bristol, UK
| | - Han A B Wösten
- Microbiology, Department of Biology, University of Utrecht, Utrecht, The Netherlands
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3
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Morita Y, Katakura Y, Takegawa K, Higuchi Y. Correlative Localization Analysis Between mRNA and Enhanced Green Fluorescence Protein-Fused Protein by a Single-Molecule Fluorescence in situ Hybridization Using an egfp Probe in Aspergillus oryzae. FRONTIERS IN FUNGAL BIOLOGY 2021; 2:721398. [PMID: 37744096 PMCID: PMC10512357 DOI: 10.3389/ffunb.2021.721398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 09/09/2021] [Indexed: 09/26/2023]
Abstract
Although subcellular localization analysis of proteins fused with enhanced green fluorescence protein (EGFP) has been widely conducted in filamentous fungi, little is known about the localization of messenger RNAs (mRNAs) encoding the EGFP-fused proteins. In this study, we performed single-molecule fluorescence in situ hybridization (smFISH) using an egfp probe to simultaneously visualize EGFP-fused proteins and their mRNAs in the hyphal cells of the filamentous fungus Aspergillus oryzae. We investigated the subcellular localization of mRNAs encoding cytoplasmic EGFP, an actin marker protein Lifeact tagged with EGFP, and several EGFP-fused proteins AoSec22, AoSnc1, AoVam3, and AoUapC that localize to the endoplasmic reticulum (ER), the apical vesicle cluster Spitzenkörper, vacuolar membrane, and plasma membrane, respectively. Visualization of these mRNAs by smFISH demonstrated that each mRNA exhibited distinct localization patterns likely depending on the mRNA sequence. In particular, we revealed that mRNAs encoding Lifeact-EGFP, EGFP-AoSec22, EGFP-AoVam3, and AoUapC-EGFP, but not cytoplasmic EGFP and EGFP-AoSnc1, were preferentially localized at the apical cell, suggesting certain mechanisms to regulate the existence of these transcripts among hyphal regions. Our findings provide the distinct localization information of each mRNA in the hyphal cells of A. oryzae.
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Affiliation(s)
| | | | | | - Yujiro Higuchi
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
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4
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Varahan S, Laxman S. Bend or break: how biochemically versatile molecules enable metabolic division of labor in clonal microbial communities. Genetics 2021; 219:iyab109. [PMID: 34849891 PMCID: PMC8633146 DOI: 10.1093/genetics/iyab109] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 06/29/2021] [Indexed: 02/05/2023] Open
Abstract
In fluctuating nutrient environments, isogenic microbial cells transition into "multicellular" communities composed of phenotypically heterogeneous cells, showing functional specialization. In fungi (such as budding yeast), phenotypic heterogeneity is often described in the context of cells switching between different morphotypes (e.g., yeast to hyphae/pseudohyphae or white/opaque transitions in Candida albicans). However, more fundamental forms of metabolic heterogeneity are seen in clonal Saccharomyces cerevisiae communities growing in nutrient-limited conditions. Cells within such communities exhibit contrasting, specialized metabolic states, and are arranged in distinct, spatially organized groups. In this study, we explain how such an organization can stem from self-organizing biochemical reactions that depend on special metabolites. These metabolites exhibit plasticity in function, wherein the same metabolites are metabolized and utilized for distinct purposes by different cells. This in turn allows cell groups to function as specialized, interdependent cross-feeding systems which support distinct metabolic processes. Exemplifying a system where cells exhibit either gluconeogenic or glycolytic states, we highlight how available metabolites can drive favored biochemical pathways to produce new, limiting resources. These new resources can themselves be consumed or utilized distinctly by cells in different metabolic states. This thereby enables cell groups to sustain contrasting, even apparently impossible metabolic states with stable transcriptional and metabolic signatures for a given environment, and divide labor in order to increase community fitness or survival. We speculate on possible evolutionary implications of such metabolic specialization and division of labor in isogenic microbial communities.
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Affiliation(s)
- Sriram Varahan
- Institute for Stem Cell Science and Regenerative Medicine (inStem), Bengaluru 560065, India
| | - Sunil Laxman
- Institute for Stem Cell Science and Regenerative Medicine (inStem), Bengaluru 560065, India
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5
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Beasley AE, Ayres P, Tegelaar M, Tsompanas MA, Adamatzky A. On electrical gates on fungal colony. Biosystems 2021; 209:104507. [PMID: 34403720 DOI: 10.1016/j.biosystems.2021.104507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/08/2021] [Accepted: 08/09/2021] [Indexed: 10/20/2022]
Abstract
Mycelium networks are promising substrates for designing unconventional computing devices providing rich topologies and geometries where signals propagate and interact. Fulfilling our long-term objectives of prototyping electrical analog computers from living mycelium networks, including networks hybridised with nanoparticles, we explore the possibility of implementing Boolean logical gates based on electrical properties of fungal colonies. We converted a 3D image-data stack of Aspergillus niger fungal colony to an Euclidean graph and modelled the colony as resistive and capacitive (RC) networks, where electrical parameters of edges were functions of the edges' lengths. We found that and, or and and-not gates are implementable in RC networks derived from the geometrical structure of the real fungal colony.
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Affiliation(s)
- Alexander E Beasley
- Centre for Engineering Research, University of Hertfordshire, UK; Unconventional Computing Laboratory, UWE, Bristol, UK
| | - Phil Ayres
- The Centre for Information Technology and Architecture, Royal Danish Academy, Copenhagen, Denmark
| | - Martin Tegelaar
- Microbiology Department, University of Utrecht, Utrecht, The Netherlands
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6
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Howell G, Bleichrodt RJ. Single Cell Analysis and Sorting of Aspergillus fumigatus by Flow Cytometry. Bio Protoc 2021; 11:e3993. [PMID: 34124294 DOI: 10.21769/bioprotoc.3993] [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: 10/28/2020] [Revised: 01/18/2021] [Accepted: 02/28/2021] [Indexed: 11/02/2022] Open
Abstract
Experimental results in fungal biology research are usually obtained as average measurements across whole populations of cells, whilst ignoring what is happening at the single cell level. Microscopy has allowed us to study single-cell behavior, but it has low throughput and cannot be used to select individual cells for downstream experiments. Here we present a method that allows for the analysis and selection of single fungal cells in high throughput by flow cytometry and fluorescence activated cell sorting (FACS), respectively. This protocol can be adapted for every fungal species that produces cells of up to 70 microns in diameter. After initial setting of the flow cytometry gates, which takes a single day, accurate single cell analysis and sorting can be performed. This method yields a throughput of thousands of cells per second. Selected cells can be subjected to downstream experiments to study single-cell behavior.
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Affiliation(s)
- Gareth Howell
- Manchester Collaborative Centre for Inflammation Research (MCCIR), Infection, Immunity, Inflammation and Repair, University of Manchester, United Kingdom
| | - Robert-Jan Bleichrodt
- Manchester Fungal Infection Group (MFIG), Infection, Immunity and Respiratory Medicine, University of Manchester, United Kingdom.,Microbiology, Department of Biology, Utrecht University, The Netherlands
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7
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Aspergillus fumigatus, One Uninucleate Species with Disparate Offspring. J Fungi (Basel) 2021; 7:jof7010030. [PMID: 33419224 PMCID: PMC7825634 DOI: 10.3390/jof7010030] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 12/22/2020] [Accepted: 12/29/2020] [Indexed: 12/18/2022] Open
Abstract
Establishment of a fungal infection due to Aspergillus fumigatus relies on the efficient germination of the airborne conidia once they penetrate the respiratory tract. However, the features of conidial germination have been poorly explored and understood in this fungal species as well as in other species of filamentous fungi. We show here that the germination of A. fumigatus is asynchronous. If the nutritional environment and extensive gene deletions can modify the germination parameters for A. fumigatus, the asynchrony is maintained in all germinative conditions tested. Even though the causes for this asynchrony of conidial germination remain unknown, asynchrony is essential for the completion of the biological cycle of this filamentous fungus.
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8
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Keizer EM, Wösten HAB, de Cock H. EphA2-Dependent Internalization of A. fumigatus Conidia in A549 Lung Cells Is Modulated by DHN-Melanin. Front Microbiol 2020; 11:534118. [PMID: 33123097 PMCID: PMC7573251 DOI: 10.3389/fmicb.2020.534118] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 09/18/2020] [Indexed: 12/15/2022] Open
Abstract
Dectin-1 and ephrin type-A receptor 2 (EphA2) receptors recognize β-glucan present in the fungal cell wall. Inhibition of Dectin-1 with the monoclonal 2a11 antibody was shown to reduce internalization of conidia of the human pathogen Aspergillus fumigatus into epithelial cells. In this study, we investigated the role of the EphA2 receptor present on A549 epithelial type II lung cells in the interaction with A. fumigatus conidia. We assessed whether EphA2 is involved in association and internalization of conidia by receptor inhibition by an antibody or by using the kinase inhibitor dasatinib. A 50% reduction of internalization of conidia was observed when this receptor was blocked with either the EphA2-specific monoclonal antibody or dasatinib, which was similar when Dectin-1 was inhibited with the 2a11 monoclonal antibody. Inhibition of both receptors reduced the internalization to 40%. EphA2 inhibition was also assessed in a hydrophobin deletion strain (ΔrodA) that exposes more β-glucan and a dihydroxynaphthalene (DHN)-melanin deletion strain (ΔpksP) that exposes more glucosamine and glycoproteins. The ΔrodA strain behaved similar to the wild-type strain with or without EphA2 inhibition. In contrast, the ΔpksP mutant showed an increase in association to the A549 cells and a decrease in internalization. Internalization was not further decreased by EphA2 inhibition. Taken together, the presence of DHN-melanin in the spore cell wall results in an EphA2-dependent internalization of conidia of A. fumigatus into A549 cells.
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Affiliation(s)
- Esther M Keizer
- Microbiology & Institute of Biomembranes, Department of Biology, Utrecht University, Utrecht, Netherlands
| | - Han A B Wösten
- Microbiology & Institute of Biomembranes, Department of Biology, Utrecht University, Utrecht, Netherlands
| | - Hans de Cock
- Microbiology & Institute of Biomembranes, Department of Biology, Utrecht University, Utrecht, Netherlands
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9
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Higuchi Y, Takegawa K. Single-Molecule FISH Reveals Subcellular Localization of α-Amylase and Actin mRNAs in the Filamentous Fungus Aspergillus oryzae. Front Microbiol 2020; 11:578862. [PMID: 33072046 PMCID: PMC7536267 DOI: 10.3389/fmicb.2020.578862] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 09/01/2020] [Indexed: 11/13/2022] Open
Abstract
The machinery for mRNA localization is one of crucial molecular structures allowing cellular spatiotemporal organization of protein synthesis. Although the molecular mechanisms underlying mRNA localization have been thoroughly investigated in unicellular organisms, little is known about multicellular and multinuclear filamentous fungi. Here, we conducted single-molecule fluorescence in situ hybridization (smFISH) to first visualize the mRNA molecules of α-amylase, which are encoded by amyB, and which are thought to be abundantly secreted from the hyphal tips of the industrially important fungus Aspergillus oryzae. Consistent with previous biochemical studies, fluorescein amidite (FAM) fluorescence derived from amyB expression was observed in A. oryzae hyphae cultured in a minimal medium containing maltose instead of glucose as the sole carbon source. Moreover, after more than 1 h incubation with fresh maltose-containing medium, the fluorescence of amyB mRNAs was observed throughout the cells, suggesting α-amylase secretion potentially from each cell, instead of the hyphal tip only. Furthermore, in cultures with complete medium containing maltose, amyB mRNAs were excluded from the tip regions, where no nuclei exist. In contrast, mRNAs of actin, encoded by actA, were localized mainly to the tip, where actin proteins also preferentially reside. Collectively, our smFISH analyses revealed distinct localization patterns of α-amylase and actin mRNAs in A. oryzae hyphal cells.
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Affiliation(s)
- Yujiro Higuchi
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | - Kaoru Takegawa
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
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10
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Adamatzky A, Tegelaar M, Wosten HA, Powell AL, Beasley AE, Mayne R. On Boolean gates in fungal colony. Biosystems 2020; 193-194:104138. [DOI: 10.1016/j.biosystems.2020.104138] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 03/27/2020] [Accepted: 03/27/2020] [Indexed: 12/21/2022]
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11
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Cell Wall Composition Heterogeneity between Single Cells in Aspergillus fumigatus Leads to Heterogeneous Behavior during Antifungal Treatment and Phagocytosis. mBio 2020; 11:mBio.03015-19. [PMID: 32398317 PMCID: PMC7218287 DOI: 10.1128/mbio.03015-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The fungus Aspergillus fumigatus can cause invasive lung diseases in immunocompromised patients resulting in high mortality. Treatment using antifungal compounds is often unsuccessful. Average population measurements hide what is happening at the individual cell level. We set out to test what impact individual differences between the cell walls of fungal conidia have on their behavior. We show that a population of cells having the same genetic background gives rise to subpopulations of cells that exhibit distinct behavior (phenotypic heterogeneity). This cell heterogeneity is dependent on the strain type, gene deletions, cell age, and environmental conditions. By looking at the individual cell level, we discovered subpopulations of cells that show differential fitness during antifungal treatment and uptake by immune cells. Aspergillus fumigatus can cause a variety of lung diseases in immunocompromised patients, including life-threatening invasive aspergillosis. There are only three main classes of antifungal drugs currently used to treat aspergillosis, and antifungal resistance is increasing. Experimental results in fungal biology research are usually obtained as average measurements across whole populations while ignoring what is happening at the single cell level. In this study, we show that conidia with the same genetic background in the same cell population at a similar developmental stage show heterogeneity in their cell wall labeling at the single cell level. We present a rigorous statistical method, newly applied to quantify the level of cell heterogeneity, which allows for direct comparison of the heterogeneity observed between treatments. We show the extent of cell wall labeling heterogeneity in dormant conidia and how the level of heterogeneity changes during germination. The degree of heterogeneity is influenced by deletions of cell wall synthesizing genes and environmental conditions, including medium composition, method of inoculation, age of conidia, and the presence of antifungals. This heterogeneity results in subpopulations of germinating conidia with heterogeneous fitness to the antifungal caspofungin, which targets cell wall synthesis and heterogeneous sensitivity of dormant conidia to phagocytosis by macrophages.
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12
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Op De Beeck M, Troein C, Siregar S, Gentile L, Abbondanza G, Peterson C, Persson P, Tunlid A. Regulation of fungal decomposition at single-cell level. THE ISME JOURNAL 2020; 14:896-905. [PMID: 31896790 PMCID: PMC7082364 DOI: 10.1038/s41396-019-0583-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 12/11/2019] [Accepted: 12/18/2019] [Indexed: 11/13/2022]
Abstract
Filamentous fungi play a key role as decomposers in Earth's nutrient cycles. In soils, substrates are heterogeneously distributed in microenvironments. Hence, individual hyphae of a mycelium may experience very different environmental conditions simultaneously. In the current work, we investigated how fungi cope with local environmental variations at single-cell level. We developed a method based on infrared spectroscopy that allows the direct, in-situ chemical imaging of the decomposition activity of individual hyphal tips. Colonies of the ectomycorrhizal Basidiomycete Paxillus involutus were grown on liquid media, while parts of colonies were allowed to colonize lignin patches. Oxidative decomposition of lignin by individual hyphae growing under different conditions was followed for a period of seven days. We identified two sub-populations of hyphal tips: one with low decomposition activity and one with much higher activity. Active cells secreted more extracellular polymeric substances and oxidized lignin more strongly. The ratio of active to inactive hyphae strongly depended on the environmental conditions in lignin patches, but was further mediated by the decomposition activity of entire mycelia. Phenotypic heterogeneity occurring between genetically identical hyphal tips may be an important strategy for filamentous fungi to cope with heterogeneous and constantly changing soil environments.
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Affiliation(s)
- Michiel Op De Beeck
- Department of Biology, Microbial Ecology Group, Lund University, Ecology Building, SE-223 62, Lund, Sweden.
| | - Carl Troein
- Department of Astronomy and Theoretical Physics, Computational Biology and Biological Physics, Lund University, Sölvegatan 14A, SE-223 62, Lund, Sweden
| | - Syahril Siregar
- Department of Astronomy and Theoretical Physics, Computational Biology and Biological Physics, Lund University, Sölvegatan 14A, SE-223 62, Lund, Sweden
| | - Luigi Gentile
- Department of Biology, Microbial Ecology Group, Lund University, Ecology Building, SE-223 62, Lund, Sweden
- Department of Chemistry and CSGI, University of Bari Aldo Moro, IT- 701 21, Bari, Italy
| | - Giuseppe Abbondanza
- Department of Physics, Synchrotron Radiation Research, Lund University, SE- 223 62, Lund, Sweden
| | - Carsten Peterson
- Department of Astronomy and Theoretical Physics, Computational Biology and Biological Physics, Lund University, Sölvegatan 14A, SE-223 62, Lund, Sweden
| | - Per Persson
- Department of Biology, Microbial Ecology Group, Lund University, Ecology Building, SE-223 62, Lund, Sweden
- Centre for Environmental and Climate Research (CEC), Lund University, Ecology Building, SE-223 62, Lund, Sweden
| | - Anders Tunlid
- Department of Biology, Microbial Ecology Group, Lund University, Ecology Building, SE-223 62, Lund, Sweden
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13
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Spatial induction of genes encoding secreted proteins in micro-colonies of Aspergillus niger. Sci Rep 2020; 10:1536. [PMID: 32001779 PMCID: PMC6992626 DOI: 10.1038/s41598-020-58535-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 01/13/2020] [Indexed: 11/21/2022] Open
Abstract
Aspergillus niger is used by the industry to produce enzymes and metabolites such as citric acid. In liquid cultures, it can grow as a dispersed mycelium or as micro-colonies with a width in the micrometer to millimeter range. Here, it was assessed whether expression of genes encoding secreted enzymes depends on mycelium morphology. To this end, expression of the reporter gene gfp from the promoters of the glucoamylase gene glaA, the feruloyl esterase gene faeA and the α-glucuronidase gene aguA was causally related to micro-colony size within a liquid shaken culture. Data could be fitted by hyperbolic functions, implying that the genes encoding these secreted proteins are expressed in a shell at the periphery of the micro-colony. The presence of such a shell was confirmed by confocal microscopy. Modelling predicted that the width of these zones was 13 to 156 µm depending on growth medium and micro-colony diameter. Together, data indicate that the highest productive micro-colonies are those colonies that have a radius ≤ the width of the peripheral expression zone.
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14
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Apical but not sub-apical hyphal compartments are self-sustaining in growth. Antonie van Leeuwenhoek 2020; 113:697-706. [PMID: 31919791 PMCID: PMC7138781 DOI: 10.1007/s10482-020-01383-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 01/02/2020] [Indexed: 12/26/2022]
Abstract
It was recently demonstrated that apical compartments of Aspergillus niger hyphae are self-sustaining in growth. This was shown by assessing the growth rate of individual hyphae before and after dissection of the second compartment. Using the same methodology, it is here demonstrated that single apical compartments of the septate fungi Penicillium chrysogenum and Schizophyllum commune as well as the 500-µm-apical region of the non-septate fungus Rhizopus stolonifer are also self-sustaining in growth. In contrast, single 2nd compartments (obtained by dissection of the first and third compartment) of the septate fungi or the region between 500 and 1000 µm from tips of R. stolonifer were severely impacted in their growth rate. In addition, it is shown that existing or newly formed branches originating from the 2nd compartments function as a backup system for hyphal growth when the apical part of the hypha of the three studied fungi is damaged. Together, it is concluded that the apical compartments/zones of the studied fungi are self-sustaining in growth. In contrast, the subapical region is not self-sustaining but functions as a backup once the apical zone is damaged. This back up system is relevant in nature because the apices of hyphae are the first to be exposed to (a)biotic stress conditions when entering an unexplored substrate.
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15
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Tegelaar M, Bleichrodt RJ, Nitsche B, Ram AFJ, Wösten HAB. Subpopulations of hyphae secrete proteins or resist heat stress in Aspergillus oryzae colonies. Environ Microbiol 2019; 22:447-455. [PMID: 31736205 PMCID: PMC6972715 DOI: 10.1111/1462-2920.14863] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 10/17/2019] [Accepted: 11/14/2019] [Indexed: 01/19/2023]
Abstract
Hyphae at the outer part of colonies of Aspergillus niger and Aspergillus oryzae are heterogeneous with respect to transcriptional and translational activity. This heterogeneity is maintained by Woronin body mediated closure of septal pores that block interhyphal mixing of cytoplasm. Indeed, heterogeneity between hyphae is abolished in ΔhexA strains that lack Woronin bodies. The subpopulation of hyphae with high transcriptional and translational activity secretes enzymes that degrade the substrate resulting in breakdown products that serve as nutrients. The role of hyphae with low transcriptional and translational activity was not yet known. Here, we show that this subpopulation is more resistant to environmental stress in A. oryzae, in particular to temperature stress, when compared to hyphae with high transcriptional and translational activity. Notably, all hyphae of the ΔhexA strain of A. oryzae were sensitive to heat stress explained by the reduced heterogeneity in this strain. Together, we show that different subpopulations of hypha secrete proteins and resist heat stress showing the complexity of a fungal mycelium.
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Affiliation(s)
- Martin Tegelaar
- Microbiology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | | | - Benjamin Nitsche
- Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands
| | - Arthur F J Ram
- Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands
| | - Han A B Wösten
- Microbiology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
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16
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Iradi-Serrano M, Tola-García L, Cortese MS, Ugalde U. The Early Asexual Development Regulator fluG Codes for a Putative Bifunctional Enzyme. Front Microbiol 2019; 10:778. [PMID: 31057506 PMCID: PMC6478659 DOI: 10.3389/fmicb.2019.00778] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 03/27/2019] [Indexed: 11/13/2022] Open
Abstract
FluG is a long recognized early regulator of asexual development in Aspergillus nidulans. fluG null mutants show profuse aerial growth and no conidial production. Initial studies reported sequence homology of FluG with a prokaryotic type I glutamine synthetase, but catalytic activity has not been demonstrated. In this study, we conducted an in-depth analysis of the FluG sequence, which revealed a single polypeptide containing a putative N-terminal amidohydrolase region linked to a putative C-terminal γ-glutamyl ligase region. Each region corresponded, separately and completely, to respective single function bacterial enzymes. Separate expression of these regions confirmed that the C-terminal region was essential for asexual development. The N-terminal region alone did not support conidial development, but contributed to increased conidial production under high nutrient availability. Point mutations directed at respective key catalytic residues in each region demonstrated that they were essential for biological function. Moreover, the substitution of the N- and C-terminal regions with homologs from Lactobacillus paracasei and Pseudomonas aeruginosa, respectively, maintained functionality, albeit with altered characteristics. Taken together, the results lead us to conclude that FluG is a bifunctional enzyme that participates in an as yet unidentified metabolic or signaling pathway involving a γ-glutamylated intermediate that contributes to developmental fate.
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Affiliation(s)
| | | | | | - Unai Ugalde
- Microbial Biochemistry Laboratory, Department of Applied Chemistry, Faculty of Chemistry, University of the Basque Country, San Sebastian, Spain
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17
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Schmieder SS, Stanley CE, Rzepiela A, van Swaay D, Sabotič J, Nørrelykke SF, deMello AJ, Aebi M, Künzler M. Bidirectional Propagation of Signals and Nutrients in Fungal Networks via Specialized Hyphae. Curr Biol 2019; 29:217-228.e4. [PMID: 30612903 DOI: 10.1016/j.cub.2018.11.058] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 10/05/2018] [Accepted: 11/23/2018] [Indexed: 11/15/2022]
Abstract
Intercellular distribution of nutrients and coordination of responses to internal and external cues via endogenous signaling molecules are hallmarks of multicellular organisms. Vegetative mycelia of multicellular fungi are syncytial networks of interconnected hyphae resulting from hyphal tip growth, branching, and fusion. Such mycelia can reach considerable dimensions and, thus, different parts can be exposed to quite different environmental conditions. Our knowledge about the mechanisms by which fungal mycelia can adjust nutrient gradients or coordinate their defense response to fungivores is scarce, in part due to limitations in technologies currently available for examining different parts of a mycelium over longer time periods at the microscopic level. Here, we combined a tailor-made microfluidic platform with time-lapse fluorescence microscopy to visualize the dynamic response of the vegetative mycelium of a basidiomycete to two different stimuli. The microfluidic platform allows simultaneous monitoring at both the colony and single-hypha level. We followed the dynamics of the distribution of a locally administered nutrient analog and the defense response to spatially confined predation by a fungivorous nematode. Although both responses of the mycelium were constrained locally, we observed long-distance propagation for both the nutrient analog and defense response in a subset of hyphae. This propagation along hyphae occurred in both acropetal and basipetal directions and, intriguingly, the direction was found to alternate every 3 hr in an individual hypha. These results suggest that multicellular fungi have, as of yet, undescribed mechanisms to coordinate the distribution of nutrients and their behavioral response upon attack by fungivores.
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Affiliation(s)
- Stefanie S Schmieder
- Department of Biology, Institute of Microbiology, ETH Zürich, Zürich, Switzerland
| | - Claire E Stanley
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zürich, Zürich, Switzerland
| | - Andrzej Rzepiela
- Scientific Center for Optical and Electron Microscopy, ETH Zürich, Switzerland
| | - Dirk van Swaay
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zürich, Zürich, Switzerland
| | - Jerica Sabotič
- Department of Biotechnology, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Simon F Nørrelykke
- Scientific Center for Optical and Electron Microscopy, ETH Zürich, Switzerland
| | - Andrew J deMello
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zürich, Zürich, Switzerland
| | - Markus Aebi
- Department of Biology, Institute of Microbiology, ETH Zürich, Zürich, Switzerland
| | - Markus Künzler
- Department of Biology, Institute of Microbiology, ETH Zürich, Zürich, Switzerland.
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18
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Zacchetti B, Wösten HA, Claessen D. Multiscale heterogeneity in filamentous microbes. Biotechnol Adv 2018; 36:2138-2149. [DOI: 10.1016/j.biotechadv.2018.10.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 09/15/2018] [Accepted: 10/01/2018] [Indexed: 12/20/2022]
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19
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Characterization of Aspergillus niger Isolated from the International Space Station. mSystems 2018; 3:mSystems00112-18. [PMID: 30246146 PMCID: PMC6143729 DOI: 10.1128/msystems.00112-18] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 08/20/2018] [Indexed: 11/20/2022] Open
Abstract
The initial characterization of the Aspergillus niger isolate JSC-093350089, collected from U.S. segment surfaces of the International Space Station (ISS), is reported, along with a comparison to the extensively studied strain ATCC 1015. Whole-genome sequencing of the ISS isolate enabled its phylogenetic placement within the A. niger/welwitschiae/lacticoffeatus clade and revealed that the genome of JSC-093350089 is within the observed genetic variance of other sequenced A. niger strains. The ISS isolate exhibited an increased rate of growth and pigment distribution compared to a terrestrial strain. Analysis of the isolate's proteome revealed significant differences in the molecular phenotype of JSC-093350089, including increased abundance of proteins involved in the A. niger starvation response, oxidative stress resistance, cell wall modulation, and nutrient acquisition. Together, these data reveal the existence of a distinct strain of A. niger on board the ISS and provide insight into the characteristics of melanized fungal species inhabiting spacecraft environments. IMPORTANCE A thorough understanding of how fungi respond and adapt to the various stimuli encountered during spaceflight presents many economic benefits and is imperative for the health of crew. As A. niger is a predominant ISS isolate frequently detected in built environments, studies of A. niger strains inhabiting closed systems may reveal information fundamental to the success of long-duration space missions. This investigation provides valuable insights into the adaptive mechanisms of fungi in extreme environments as well as countermeasures to eradicate unfavorable microbes. Further, it enhances understanding of host-microbe interactions in closed systems, which can help NASA's Human Research Program maintain a habitat healthy for crew during long-term manned space missions.
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20
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Zhang T, Ren P, De Jesus M, Chaturvedi V, Chaturvedi S. Green Fluorescent Protein Expression in Pseudogymnoascus destructans to Study Its Abiotic and Biotic Lifestyles. Mycopathologia 2018; 183:805-814. [PMID: 29987576 DOI: 10.1007/s11046-018-0285-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 06/28/2018] [Indexed: 12/11/2022]
Abstract
Pseudogymnoascus destructans (Pd) is the etiologic agent of bat White-nose syndrome, a disease that has caused the unprecedented reduction in the hibernating bat populations across eastern North America. The Pd pathogenesis appears to be a complex adaptation of fungus in its abiotic (caves and mines) and biotic (bats) environments. There is a general lack of experimental tools for the study of Pd biology. We described the successful expression of codon-optimized synthetic green fluorescent protein sGFP in Pd. The sGFP(S65T) gene was first fused in frame with the Aspergillus nidulans promoter in the tumor-inducing plasmid pRF-HUE, and the resulting plasmid pHUE-sGFP(S65T) was transformed into Pd by Agrobacterium tumefaciens-mediated transformation system. The integration of sGFP(S65T) in Pd genome was analyzed by PCR, and single integration frequency of approximately 66% was confirmed by Southern hybridization. Fluorescent microscopy and flow cytometric analyses of two randomly selected transformants with single integration revealed high expression of sGFP in both spores and hyphal structures. The biology of mutants as judged by sporulation, growth rate, and urease production was not altered indicating sGFP is not toxic to Pd. Thus, we have generated a valuable tool that will facilitate the elucidation of Pd biology, ecology, and pathogenicity in real time.
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Affiliation(s)
- Tao Zhang
- Mycology Laboratory, Wadsworth Center, New York State Department of Health, Albany, NY, USA
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, People's Republic of China
| | - Ping Ren
- Mycology Laboratory, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Magdia De Jesus
- Immunology and Infectious Disease Laboratory, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Vishnu Chaturvedi
- Mycology Laboratory, Wadsworth Center, New York State Department of Health, Albany, NY, USA.
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, USA.
| | - Sudha Chaturvedi
- Mycology Laboratory, Wadsworth Center, New York State Department of Health, Albany, NY, USA.
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, USA.
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21
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Tegelaar M, Wösten HAB. Functional distinction of hyphal compartments. Sci Rep 2017; 7:6039. [PMID: 28729612 PMCID: PMC5519613 DOI: 10.1038/s41598-017-06422-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 06/12/2017] [Indexed: 12/02/2022] Open
Abstract
Hyphae of higher fungi grow at their tips and are compartmentalized by porous septa that enable inter-compartmental cytoplasmic streaming. Woronin bodies discontinue cytoplasmic streaming by plugging the septal pores. Here, it was assessed whether apical compartments of Aspergillus niger sustain their own growth or whether their growth depends on subapical compartments. Hyphae of wildtype and the ΔhexA strain, lacking Woronin bodies, had a similar morphology and growth rate. A total of 58% and 17% of the hyphae continued growing, respectively, after dissecting the 2nd compartment. Extension rate of the apical compartments that continued growing was not affected, even when the carbon or nitrogen source was limiting. Thus, apical compartments are self-sustaining in growth. It was also shown that the first 8 subapical compartments of the wildtype, but not of the ΔhexA strain, function as a backup system for growth by forming new branches when their apical neighbouring compartment has been damaged. This backup system is pivotal in nature because of the life style of fungi to continuously explore their surrounding substrate that may prove hostile.
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Affiliation(s)
- Martin Tegelaar
- Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Han A B Wösten
- Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
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22
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Abstract
Filamentous fungi are a large and ancient clade of microorganisms that occupy a broad range of ecological niches. The success of filamentous fungi is largely due to their elongate hypha, a chain of cells, separated from each other by septa. Hyphae grow by polarized exocytosis at the apex, which allows the fungus to overcome long distances and invade many substrates, including soils and host tissues. Hyphal tip growth is initiated by establishment of a growth site and the subsequent maintenance of the growth axis, with transport of growth supplies, including membranes and proteins, delivered by motors along the cytoskeleton to the hyphal apex. Among the enzymes delivered are cell wall synthases that are exocytosed for local synthesis of the extracellular cell wall. Exocytosis is opposed by endocytic uptake of soluble and membrane-bound material into the cell. The first intracellular compartment in the endocytic pathway is the early endosomes, which emerge to perform essential additional functions as spatial organizers of the hyphal cell. Individual compartments within septated hyphae can communicate with each other via septal pores, which allow passage of cytoplasm or organelles to help differentiation within the mycelium. This article introduces the reader to more detailed aspects of hyphal growth in fungi.
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23
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Production of taxadiene by engineering of mevalonate pathway in Escherichia coli
and endophytic fungus Alternaria alternata
TPF6. Biotechnol J 2017; 12. [DOI: 10.1002/biot.201600697] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 02/13/2017] [Accepted: 02/16/2017] [Indexed: 11/07/2022]
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24
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Maturation of conidia on conidiophores of Aspergillus niger. Fungal Genet Biol 2017; 98:61-70. [DOI: 10.1016/j.fgb.2016.12.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 12/12/2016] [Accepted: 12/19/2016] [Indexed: 11/23/2022]
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25
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Zhang Z, Claessen D, Rozen DE. Understanding Microbial Divisions of Labor. Front Microbiol 2016; 7:2070. [PMID: 28066387 PMCID: PMC5174093 DOI: 10.3389/fmicb.2016.02070] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 12/07/2016] [Indexed: 12/27/2022] Open
Abstract
Divisions of labor are ubiquitous in nature and can be found at nearly every level of biological organization, from the individuals of a shared society to the cells of a single multicellular organism. Many different types of microbes have also evolved a division of labor among its colony members. Here we review several examples of microbial divisions of labor, including cases from both multicellular and unicellular microbes. We first discuss evolutionary arguments, derived from kin selection, that allow divisions of labor to be maintained in the face of non-cooperative cheater cells. Next we examine the widespread natural variation within species in their expression of divisions of labor and compare this to the idea of optimal caste ratios in social insects. We highlight gaps in our understanding of microbial caste ratios and argue for a shift in emphasis from understanding the maintenance of divisions of labor, generally, to instead focusing on its specific ecological benefits for microbial genotypes and colonies. Thus, in addition to the canonical divisions of labor between, e.g., reproductive and vegetative tasks, we may also anticipate divisions of labor to evolve to reduce the costly production of secondary metabolites or secreted enzymes, ideas we consider in the context of streptomycetes. The study of microbial divisions of labor offers opportunities for new experimental and molecular insights across both well-studied and novel model systems.
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Affiliation(s)
- Zheren Zhang
- Institute of Biology, Leiden University Leiden, Netherlands
| | | | - Daniel E Rozen
- Institute of Biology, Leiden University Leiden, Netherlands
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26
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Hewitt SK, Foster DS, Dyer PS, Avery SV. Phenotypic heterogeneity in fungi: Importance and methodology. FUNGAL BIOL REV 2016. [DOI: 10.1016/j.fbr.2016.09.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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27
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Escobar N, Ordonez SR, Wösten HAB, Haas PJA, de Cock H, Haagsman HP. Hide, Keep Quiet, and Keep Low: Properties That Make Aspergillus fumigatus a Successful Lung Pathogen. Front Microbiol 2016; 7:438. [PMID: 27092115 PMCID: PMC4821987 DOI: 10.3389/fmicb.2016.00438] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 03/18/2016] [Indexed: 12/29/2022] Open
Abstract
Representatives of the genus Aspergillus are opportunistic fungal pathogens. Their conidia can reach the alveoli by inhalation and can give rise to infections in immunocompromised individuals. Aspergillus fumigatus is the causal agent of invasive aspergillosis in nearly 90% of the cases. It is not yet well-established what makes this fungus more pathogenic than other aspergilli such as A. niger. Here, we show that A. fumigatus and A. niger conidia adhere with similar efficiency to lung epithelial A549 cells but A. fumigatus conidia internalized 17% more efficiently. Conidia of both aspergilli were taken up in phagolysosomes 8 h after the challenge. These organelles only acidified in the case of A. niger, which is probably due to the type of melanin coating of the conidia. Viability of both types of conidia was not affected after uptake in the phagolysosomes. Germination of A. fumigatus and A. niger conidia in the presence of epithelial cells was delayed when compared to conidia in the medium. However, germination of A. niger conidia was still higher than that of A. fumigatus 10 h after exposure to A549 cells. Remarkably, A. fumigatus hyphae grew mainly parallel to the epithelium, while growth direction of A. niger hyphae was predominantly perpendicular to the plane of the cells. Neutrophils reduced germination and hyphal growth of A. niger, but not of A fumigatus, in presence of epithelial cells. Taken together, efficient internalization, delayed germination, and hyphal growth parallel to the epithelium gives a new insight into what could be the causes for the success of A. fumigatus compared to A. niger as an opportunistic pathogen in the lung.
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Affiliation(s)
- Natalia Escobar
- Department of Microbiology, Institute of Biomembranes, Utrecht UniversityUtrecht, Netherlands
| | - Soledad R. Ordonez
- Department of Infectious Diseases and Immunology, Division Molecular Host Defence, Utrecht UniversityUtrecht, Netherlands
| | - Han A. B. Wösten
- Department of Microbiology, Institute of Biomembranes, Utrecht UniversityUtrecht, Netherlands
| | - Pieter-Jan A. Haas
- Department of Medical Microbiology, University Medical Center UtrechtUtrecht, Netherlands
| | - Hans de Cock
- Department of Microbiology, Institute of Biomembranes, Utrecht UniversityUtrecht, Netherlands
| | - Henk P. Haagsman
- Department of Infectious Diseases and Immunology, Division Molecular Host Defence, Utrecht UniversityUtrecht, Netherlands
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28
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Bleichrodt RJ, Vinck A, Read ND, Wösten HAB. Selective transport between heterogeneous hyphal compartments via the plasma membrane lining septal walls of Aspergillus niger. Fungal Genet Biol 2015. [PMID: 26212073 DOI: 10.1016/j.fgb.2015.06.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Hyphae of ascomycetes are compartmentalized by septa. The central pore in these septa allows for cytoplasmic streaming. However, many of these pores are closed by Woronin bodies in Aspergillus, which prevents cytoplasmic mixing and thus maintains hyphal heterogeneity. Here, glucose uptake and transport was studied in Aspergillus niger. Glucose uptake was higher in the hyphal population with high transcriptional activity when compared to the population with low transcriptional activity. Glucose was transported from the colony center to the periphery, but not vice versa. This unidirectional flow was similar in the wild-type and the ΔhexA strain that does not form Woronin bodies. This indicated that septal plugging by Woronin bodies does not impact long distance glucose transport. Indeed, the glucose analogue 2-NBDG (2-(N-[7-nitrobenz-2-oxa-1,3-diazol-4-yl]amino)-2-deoxyglucose) translocated to neighboring hyphal compartments despite Woronin body mediated plugging of the septum that separated these compartments. Notably, 2-NBDG accumulated in septal cross walls, indicating that intercompartmental glucose transport is mediated by transporters that reside in the plasma membrane lining the septal cross-wall. The presence of such transporters would thus enable selective transport between heterogeneous compartments.
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Affiliation(s)
- Robert-Jan Bleichrodt
- Microbiology and Kluyver Center for Genomics of Industrial Fermentation, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands; Manchester Fungal Infection Group, Institute of Inflammation and Repair, University of Manchester, CTF Building, 46 Grafton Street, Manchester M13 9NT, United Kingdom.
| | - Arman Vinck
- Microbiology and Kluyver Center for Genomics of Industrial Fermentation, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
| | - Nick D Read
- Manchester Fungal Infection Group, Institute of Inflammation and Repair, University of Manchester, CTF Building, 46 Grafton Street, Manchester M13 9NT, United Kingdom.
| | - Han A B Wösten
- Microbiology and Kluyver Center for Genomics of Industrial Fermentation, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
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29
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Abstract
UNLABELLED Pores in fungal septa enable cytoplasmic streaming between hyphae and their compartments. Consequently, the mycelium can be considered unicellular. However, we show here that Woronin bodies close ~50% of the three most apical septa of growing hyphae of Aspergillus niger. The incidence of closure of the 9th and 10th septa was even ≥94%. Intercompartmental streaming of photoactivatable green fluorescent protein (PA-GFP) was not observed when the septa were closed, but open septa acted as a barrier, reducing the mobility rate of PA-GFP ~500 times. This mobility rate decreased with increasing septal age and under stress conditions, likely reflecting a regulatory mechanism affecting septal pore diameter. Modeling revealed that such regulation offers effective control of compound concentration between compartments. Modeling also showed that the incidence of septal closure in A. niger had an even stronger impact on cytoplasmic continuity. Cytoplasm of hyphal compartments was shown not to be in physical contact when separated by more than 4 septa. Together, data show that apical compartments of growing hyphae behave unicellularly, while older compartments have a multicellular organization. IMPORTANCE The hyphae of higher fungi are compartmentalized by porous septa that enable cytosolic streaming. Therefore, it is believed that the mycelium shares cytoplasm. However, it is shown here that the septa of Aspergillus niger are always closed in the oldest part of the hyphae, and therefore, these compartments are physically isolated from each other. In contrast, only part of the septa is closed in the youngest part of the hyphae. Still, compartments in this hyphal part are physically isolated when separated by more than 4 septa. Even open septa act as a barrier for cytoplasmic mixing. The mobility rate through such septa reduces with increasing septal age and under stress conditions. Modeling shows that the septal pore width is set such that its regulation offers maximal control of compound concentration levels within the compartments. Together, we show for the first time that Aspergillus hyphae switch from a unicellular to multicellular organization.
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30
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Meyer V, Fiedler M, Nitsche B, King R. The Cell Factory Aspergillus Enters the Big Data Era: Opportunities and Challenges for Optimising Product Formation. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2015; 149:91-132. [PMID: 25616499 DOI: 10.1007/10_2014_297] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Living with limits. Getting more from less. Producing commodities and high-value products from renewable resources including waste. What is the driving force and quintessence of bioeconomy outlines the lifestyle and product portfolio of Aspergillus, a saprophytic genus, to which some of the top-performing microbial cell factories belong: Aspergillus niger, Aspergillus oryzae and Aspergillus terreus. What makes them so interesting for exploitation in biotechnology and how can they help us to address key challenges of the twenty-first century? How can these strains become trimmed for better growth on second-generation feedstocks and how can we enlarge their product portfolio by genetic and metabolic engineering to get more from less? On the other hand, what makes it so challenging to deduce biological meaning from the wealth of Aspergillus -omics data? And which hurdles hinder us to model and engineer industrial strains for higher productivity and better rheological performance under industrial cultivation conditions? In this review, we will address these issues by highlighting most recent findings from the Aspergillus research with a focus on fungal growth, physiology, morphology and product formation. Indeed, the last years brought us many surprising insights into model and industrial strains. They clearly told us that similar is not the same: there are different ways to make a hypha, there are more protein secretion routes than anticipated and there are different molecular and physical mechanisms which control polar growth and the development of hyphal networks. We will discuss new conceptual frameworks derived from these insights and the future scientific advances necessary to create value from Aspergillus Big Data.
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Affiliation(s)
- Vera Meyer
- Department Applied and Molecular Microbiology, Institute of Biotechnology, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355, Berlin, Germany,
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31
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Stanley CE, Stöckli M, van Swaay D, Sabotič J, Kallio PT, Künzler M, deMello AJ, Aebi M. Probing bacterial–fungal interactions at the single cell level. Integr Biol (Camb) 2014; 6:935-45. [DOI: 10.1039/c4ib00154k] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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32
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de Bekker C, Merrow M, Hughes DP. From behavior to mechanisms: an integrative approach to the manipulation by a parasitic fungus (Ophiocordyceps unilateralis s.l.) of its host ants (Camponotus spp.). Integr Comp Biol 2014; 54:166-76. [PMID: 24907198 DOI: 10.1093/icb/icu063] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Co-evolution of parasites and their hosts has led to certain parasites adaptively manipulating the behavior of their hosts. Although the number of examples from different taxa for this phenomenon is growing, the mechanisms underlying parasite-induced manipulation of hosts' behavior are still poorly understood. The development of laboratory infections integrating various disciplines within the life sciences is an important step in that direction. Here, we advocate for such an integrative approach using the parasitic fungi of the genus Ophiocordyceps that induce an adaptive biting behavior in Camponotus ants as an example. We emphasize the use of behavioral assays under controlled laboratory conditions, the importance of temporal aspects of the behavior (possibly involving the circadian clock), and the need to approach colonizing parasites as organizations with a division of labor.
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Affiliation(s)
- Charissa de Bekker
- *Department of Entomology and Biology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, State College, PA 16802, USA; Institute of Medical Psychology, Faculty of Medicine, Ludwig Maximilians Universität München, 80336 Munich, Germany
| | - Martha Merrow
- *Department of Entomology and Biology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, State College, PA 16802, USA; Institute of Medical Psychology, Faculty of Medicine, Ludwig Maximilians Universität München, 80336 Munich, Germany
| | - David P Hughes
- *Department of Entomology and Biology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, State College, PA 16802, USA; Institute of Medical Psychology, Faculty of Medicine, Ludwig Maximilians Universität München, 80336 Munich, Germany
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33
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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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Monitoring the metabolic state of fungal hyphae and the presence of melanin by nonlinear spectral imaging. Appl Environ Microbiol 2013; 79:6345-50. [PMID: 23934488 DOI: 10.1128/aem.02291-13] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Label-free nonlinear spectral imaging microscopy (NLSM) records two-photon-excited fluorescence emission spectra of endogenous fluorophores within the specimen. Here, NLSM is introduced as a novel, minimally invasive method to analyze the metabolic state of fungal hyphae by monitoring the autofluorescence of NAD(P)H and flavin adenine dinucleotide (FAD). Moreover, the presence of melanin was analyzed by NLSM. NAD(P)H, FAD, and melanin were used as biomarkers for freshness of mushrooms of Agaricus bisporus (white button mushroom) that had been stored at 4°C for 0 to 17 days. During this period, the mushrooms did not show changes in morphology or color detectable by eye. In contrast, FAD/NAD(P)H and melanin/NAD(P)H ratios increased over time. For instance, these ratios increased from 0.92 to 2.02 and from 0.76 to 1.53, respectively, at the surface of mushroom caps that had been harvested by cutting the stem. These ratios were lower under the skin than at the surface of fresh mushrooms (0.78 versus 0.92 and 0.41 versus 0.76, respectively), indicative of higher metabolism and lower pigment formation within the fruiting body. Signals were different not only between tissues of the mushroom but also between neighboring hyphae. These data show that NLSM can be used to determine the freshness of mushrooms and to monitor the postharvest browning process at an early stage. Moreover, these data demonstrate the potential of NLSM to address a broad range of fundamental and applied microbiological processes.
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Wösten HAB, van Veluw GJ, de Bekker C, Krijgsheld P. Heterogeneity in the mycelium: implications for the use of fungi as cell factories. Biotechnol Lett 2013; 35:1155-64. [PMID: 23592308 DOI: 10.1007/s10529-013-1210-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 04/05/2013] [Indexed: 11/29/2022]
Abstract
Fungi are widely used as cell factories for the production of pharmaceutical compounds, enzymes and metabolites. Fungi form colonies that consist of a network of hyphae. During the last two decades it has become clear that fungal colonies within a liquid culture are heterogeneous in size and gene expression. Heterogeneity in growth, secretion, and RNA composition can even be found between and within zones of colonies. These findings imply that productivity in a bioreactor may be increased by reducing the heterogeneity within the culture. The results also imply that molecular mechanisms underlying productivity of fungi in bioreactors should not be studied at the culture level but at the level of micro-colony populations or even at zonal or hyphal level.
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Affiliation(s)
- Han A B Wösten
- Department of Microbiology, Kluyver Centre for Genomics of Industrial Fermentation Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
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37
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Krijgsheld P, Bleichrodt R, van Veluw G, Wang F, Müller W, Dijksterhuis J, Wösten H. Development in Aspergillus. Stud Mycol 2013; 74:1-29. [PMID: 23450714 PMCID: PMC3563288 DOI: 10.3114/sim0006] [Citation(s) in RCA: 232] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The genus Aspergillus represents a diverse group of fungi that are among the most abundant fungi in the world. Germination of a spore can lead to a vegetative mycelium that colonizes a substrate. The hyphae within the mycelium are highly heterogeneous with respect to gene expression, growth, and secretion. Aspergilli can reproduce both asexually and sexually. To this end, conidiophores and ascocarps are produced that form conidia and ascospores, respectively. This review describes the molecular mechanisms underlying growth and development of Aspergillus.
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Affiliation(s)
- P. Krijgsheld
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - R. Bleichrodt
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - G.J. van Veluw
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - F. Wang
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - W.H. Müller
- Biomolecular Imaging, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - J. Dijksterhuis
- Applied and Industrial Mycology, CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - H.A.B. Wösten
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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38
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PREFACE. Stud Mycol 2013. [DOI: 10.1016/s0166-0616(14)60082-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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39
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Systems metabolic engineering in an industrial setting. Appl Microbiol Biotechnol 2013; 97:2319-26. [DOI: 10.1007/s00253-013-4738-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 01/22/2013] [Accepted: 01/23/2013] [Indexed: 10/27/2022]
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Jedd G, Pieuchot L. Multiple modes for gatekeeping at fungal cell-to-cell channels. Mol Microbiol 2012; 86:1291-4. [PMID: 23127137 DOI: 10.1111/mmi.12074] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/15/2012] [Indexed: 12/23/2022]
Abstract
Cell-to-cell channels appear to be indispensable for successful multicellular organization and arose independently in animals, plants and fungi. Most of the fungi obtain nutrients from the environment by growing in an exploratory and invasive manner, and this ability depends on multicellular filaments known as hyphae. These cells grow by tip extension and can be divided into compartments by cell walls that typically retain a central pore that allows intercellular transport and cooperation. In the major clade of filamentous Ascomycota, integrity of this coenocytic organization is maintained by Woronin body organelles, which function as emergency patches of septal pores. In this issue of Molecular Microbiology, Bleichrodt and co-workers show that Woronin bodies can also form tight reversible associations with the pore and further link this to variation in levels of compartmental gene expression. These data define an additional modality of Woronin body-dependent gatekeeping. This commentary focuses on the implications of this work and the potential role of different modes of pore gating in controlling the growth and development of fungal tissues.
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Affiliation(s)
- Gregory Jedd
- Temasek Life Sciences Laboratory and Department of Biological Sciences, National University of Singapore, Singapore.
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41
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Bleichrodt RJ, van Veluw GJ, Recter B, Maruyama JI, Kitamoto K, Wösten HAB. Hyphal heterogeneity in Aspergillus oryzae is the result of dynamic closure of septa by Woronin bodies. Mol Microbiol 2012; 86:1334-44. [PMID: 23106143 DOI: 10.1111/mmi.12077] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/15/2012] [Indexed: 11/24/2022]
Abstract
Hyphae of higher fungi are compartmentalized by septa. These septa contain a central pore that allows for inter-compartmental and inter-hyphal cytoplasmic streaming. The cytoplasm within the mycelium is therefore considered to be a continuous system. In this study, however, we demonstrate by laser dissection that 40% of the apical septa of exploring hyphae of Aspergillus oryzae are closed. Closure of septa correlated with the presence of a peroxisome-derived organelle, known as Woronin body, near the septal pore. The location of Woronin bodies in the hyphae was dynamic and, as a result, plugging of the septal pore was reversible. Septal plugging was abolished in a ΔAohex1 strain that cannot form Woronin bodies. Notably, hyphal heterogeneity was also affected in the ΔAohex1 strain. Wild-type strains of A. oryzae showed heterogeneous distribution of GFP between neighbouring hyphae at the outer part of the colony when the reporter was expressed from the promoter of the glucoamylase gene glaA or the α-glucuronidase gene aguA. In contrast, GFP fluorescence showed a normal distribution in the case of the ΔAohex1 strain. Taken together, it is concluded that Woronin bodies maintain hyphal heterogeneity in a fungal mycelium by impeding cytoplasmic continuity.
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Affiliation(s)
- Robert-Jan Bleichrodt
- Department of Microbiology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
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42
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van Veluw GJ, Teertstra WR, de Bekker C, Vinck A, van Beek N, Muller WH, Arentshorst M, van der Mei HC, Ram AFJ, Dijksterhuis J, Wösten HAB. Heterogeneity in liquid shaken cultures of Aspergillus niger inoculated with melanised conidia or conidia of pigmentation mutants. Stud Mycol 2012; 74:47-57. [PMID: 23449476 PMCID: PMC3563290 DOI: 10.3114/sim0008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Black pigmented conidia of Aspergillus niger give rise to micro-colonies when incubated in liquid shaken medium. These micro-colonies are heterogeneous with respect to gene expression and size. We here studied the biophysical properties of the conidia of a control strain and of strains in which the fwnA, olvA or brnA gene is inactivated. These strains form fawn-, olive-, and brown-coloured conidia, respectively. The ΔolvA strain produced larger conidia (3.8 μm) when compared to the other strains (3.2-3.3 μm). Moreover, the conidia of the ΔolvA strain were highly hydrophilic, whereas those of the other strains were hydrophobic. The zeta potential of the ΔolvA conidia in medium was also more negative when compared to the control strain. This was accompanied by the near absence of a rodlet layer of hydrophobins. Using the Complex Object Parametric Analyzer and Sorter it was shown that the ratio of individual hyphae and micro-colonies in liquid shaken cultures of the deletion strains was lower when compared to the control strain. The average size of the micro-colonies of the control strain was also smaller (628 μm) than that of the deletion strains (790-858 μm). The size distribution of the micro-colonies of the ΔfwnA strain was normally distributed, while that of the other strains could be explained by assuming a population of small and a population of large micro-colonies. In the last set of experiments it was shown that relative expression levels of gpdA, and AmyR and XlnR regulated genes correlate in individual hyphae at the periphery of micro-colonies. This indicates the existence of transcriptionally and translationally highly active and lowly active hyphae as was previously shown in macro-colonies. However, the existence of distinct populations of hyphae with high and low transcriptional and translational activity seems to be less robust when compared to macro-colonies grown on solid medium.
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Affiliation(s)
- G J van Veluw
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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Bleichrodt R, Vinck A, Krijgsheld P, van Leeuwen MR, Dijksterhuis J, Wösten HAB. Cytosolic streaming in vegetative mycelium and aerial structures of Aspergillus niger. Stud Mycol 2012; 74:31-46. [PMID: 23450745 PMCID: PMC3563289 DOI: 10.3114/sim0007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Aspergillus niger forms aerial hyphae and conidiophores after a period of vegetative growth. The hyphae within the mycelium of A. niger are divided by septa. The central pore in these septa allows for cytoplasmic streaming. Here, we studied inter- and intra-compartmental streaming of the reporter protein GFP in A. niger. Expression of the gene encoding nuclear targeted GFP from the gpdA or glaA promoter resulted in strong fluorescence of nuclei within the vegetative hyphae and weak fluorescence in nuclei within the aerial structures. These data and nuclear run on experiments showed that gpdA and glaA are higher expressed in the vegetative mycelium when compared to aerial hyphae, conidiophores and conidia. Notably, gpdA or glaA driven expression of the gene encoding cytosolic GFP resulted in strongly fluorescent vegetative hyphae and aerial structures. Apparently, GFP streams from vegetative hyphae into aerial structures. This was confirmed by monitoring fluorescence of photo-activatable GFP (PA-GFP). In contrast, PA-GFP did not stream from aerial structures to vegetative hyphae. Streaming of PA-GFP within vegetative hyphae or within aerial structures of A. niger occurred at a rate of 10–15 μm s-1. Taken together, these results not only show that GFP streams from the vegetative mycelium to aerial structures but it also indicates that its encoding RNA is not streaming. Absence of RNA streaming would explain why distinct RNA profiles were found in aerial structures and the vegetative mycelium by nuclear run on analysis and micro-array analysis.
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Affiliation(s)
- R Bleichrodt
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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44
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Schubert M, Bleuler-Martinez S, Butschi A, Wälti MA, Egloff P, Stutz K, Yan S, Wilson IBH, Hengartner MO, Aebi M, Allain FHT, Künzler M. Plasticity of the β-trefoil protein fold in the recognition and control of invertebrate predators and parasites by a fungal defence system. PLoS Pathog 2012; 8:e1002706. [PMID: 22615566 PMCID: PMC3355094 DOI: 10.1371/journal.ppat.1002706] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 04/02/2012] [Indexed: 11/29/2022] Open
Abstract
Discrimination between self and non-self is a prerequisite for any defence mechanism; in innate defence, this discrimination is often mediated by lectins recognizing non-self carbohydrate structures and so relies on an arsenal of host lectins with different specificities towards target organism carbohydrate structures. Recently, cytoplasmic lectins isolated from fungal fruiting bodies have been shown to play a role in the defence of multicellular fungi against predators and parasites. Here, we present a novel fruiting body lectin, CCL2, from the ink cap mushroom Coprinopsis cinerea. We demonstrate the toxicity of the lectin towards Caenorhabditis elegans and Drosophila melanogaster and present its NMR solution structure in complex with the trisaccharide, GlcNAcβ1,4[Fucα1,3]GlcNAc, to which it binds with high specificity and affinity in vitro. The structure reveals that the monomeric CCL2 adopts a β-trefoil fold and recognizes the trisaccharide by a single, topologically novel carbohydrate-binding site. Site-directed mutagenesis of CCL2 and identification of C. elegans mutants resistant to this lectin show that its nematotoxicity is mediated by binding to α1,3-fucosylated N-glycan core structures of nematode glycoproteins; feeding with fluorescently labeled CCL2 demonstrates that these target glycoproteins localize to the C. elegans intestine. Since the identified glycoepitope is characteristic for invertebrates but absent from fungi, our data show that the defence function of fruiting body lectins is based on the specific recognition of non-self carbohydrate structures. The trisaccharide specifically recognized by CCL2 is a key carbohydrate determinant of pollen and insect venom allergens implying this particular glycoepitope is targeted by both fungal defence and mammalian immune systems. In summary, our results demonstrate how the plasticity of a common protein fold can contribute to the recognition and control of antagonists by an innate defence mechanism, whereby the monovalency of the lectin for its ligand implies a novel mechanism of lectin-mediated toxicity.
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Affiliation(s)
- Mario Schubert
- Institute of Molecular Biology and Biophysics, ETH Zürich, Zürich, Switzerland
| | | | - Alex Butschi
- Institute of Molecular Life Sciences, University of Zürich, Switzerland
| | | | - Pascal Egloff
- Institute of Microbiology, ETH Zürich, Zürich, Switzerland
| | - Katrin Stutz
- Institute of Molecular Life Sciences, University of Zürich, Switzerland
| | - Shi Yan
- Department of Chemistry, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Iain B. H. Wilson
- Department of Chemistry, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | | | - Markus Aebi
- Institute of Microbiology, ETH Zürich, Zürich, Switzerland
| | | | - Markus Künzler
- Institute of Microbiology, ETH Zürich, Zürich, Switzerland
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Krijgsheld P, Altelaar AFM, Post H, Ringrose JH, Müller WH, Heck AJR, Wösten HAB. Spatially resolving the secretome within the mycelium of the cell factory Aspergillus niger. J Proteome Res 2012; 11:2807-18. [PMID: 22443316 DOI: 10.1021/pr201157b] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Aspergillus niger is an important cell factory for the industrial production of enzymes. These enzymes are released into the culture medium, from which they can be easily isolated. Here, we determined with stable isotope dimethyl labeling the secretome of five concentric zones of 7-day-old xylose-grown colonies of A. niger that had either or not been treated with cycloheximide. As expected, cycloheximide blocked secretion of proteins at the periphery of the colony. Unexpectedly, protein release was increased by cycloheximide in the intermediate and central zones of the mycelium when compared to nontreated colonies. Electron microscopy indicated that this is due to partial degradation of the cell wall. In total, 124 proteins were identified in cycloheximide-treated colonies, of which 19 secreted proteins had not been identified before. Within the pool of 124 proteins, 53 secreted proteins were absent in nontreated colonies, and additionally, 35 proteins were released ≥4-fold in the central and subperipheral zones of cycloheximide-treated colonies when compared to nontreated colonies. The composition of the secretome in each of the five concentric zones differed. This study thus describes spatial release of proteins in A. niger, which is instrumental in understanding how fungi degrade complex substrates in nature.
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Affiliation(s)
- Pauline Krijgsheld
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentation, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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46
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Abstract
Genetic variation between individuals is essential to evolution and adaptation. However, intra-organismic genetic variation also shapes the life histories of many organisms, including filamentous fungi. A single fungal syncytium can harbor thousands or millions of mobile and potentially genotypically different nuclei, each having the capacity to regenerate a new organism. Because the dispersal of asexual or sexual spores propagates individual nuclei in many of these species, selection acting at the level of nuclei creates the potential for competitive and cooperative genome dynamics. Recent work in Neurospora crassa and Sclerotinia sclerotiorum has illuminated how nuclear populations are coordinated for fungal growth and other behaviors and has revealed both molecular and physical mechanisms for preventing and policing inter-genomic conflict. Recent results from population-level genomic studies in a variety of filamentous fungi suggest that nuclear exchange between mycelia and recombination between heterospecific nuclei may be of more importance to fungal evolution, diversity and the emergence of newly virulent strains than has previously been recognized.
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Affiliation(s)
- Marcus Roper
- Department of Mathematics, University of California, Berkeley, USA
- Mathematics Institute, University of Warwick, Coventry CV4 7AL, UK
| | - Chris Ellison
- Department of Plant and Microbial Biology, University of California, Berkeley, USA
| | - John W. Taylor
- Department of Plant and Microbial Biology, University of California, Berkeley, USA
| | - N. Louise Glass
- Department of Plant and Microbial Biology, University of California, Berkeley, USA
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47
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de Bekker C, Bruning O, Jonker MJ, Breit TM, Wösten HAB. Single cell transcriptomics of neighboring hyphae of Aspergillus niger. Genome Biol 2011; 12:R71. [PMID: 21816052 PMCID: PMC3245611 DOI: 10.1186/gb-2011-12-8-r71] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 08/04/2011] [Indexed: 11/10/2022] Open
Abstract
Single cell profiling was performed to assess differences in RNA accumulation in neighboring hyphae of the fungus Aspergillus niger. A protocol was developed to isolate and amplify RNA from single hyphae or parts thereof. Microarray analysis resulted in a present call for 4 to 7% of the A. niger genes, of which 12% showed heterogeneous RNA levels. These genes belonged to a wide range of gene categories.
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Affiliation(s)
- Charissa de Bekker
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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48
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Heterogeneity of Aspergillus niger microcolonies in liquid shaken cultures. Appl Environ Microbiol 2010; 77:1263-7. [PMID: 21169437 DOI: 10.1128/aem.02134-10] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The fungus Aspergillus niger forms (sub)millimeter microcolonies within a liquid shaken culture. Here, we show that such microcolonies are heterogeneous with respect to size and gene expression. Microcolonies of strains expressing green fluorescent protein (GFP) from the promoter of the glucoamlyase gene glaA or the ferulic acid esterase gene faeA were sorted on the basis of diameter and fluorescence using the Complex Object Parametric Analyzer and Sorter (COPAS) technology. Statistical analysis revealed that the liquid shaken culture consisted of two populations of microcolonies that differ by 90 μm in diameter. The population of small microcolonies of strains expressing GFP from the glaA or faeA promoter comprised 39% and 25% of the culture, respectively. Two populations of microcolonies could also be distinguished when the expression of GFP in these strains was analyzed. The population expressing a low level of GFP consisted of 68% and 44% of the culture, respectively. We also show that mRNA accumulation is heterogeneous within microcolonies of A. niger. Central and peripheral parts of the mycelium were isolated with laser microdissection and pressure catapulting (LMPC), and RNA from these samples was used for quantitative PCR analysis. This analysis showed that the RNA content per hypha was about 45 times higher at the periphery than in the center of the microcolony. Our data imply that the protein production of A. niger can be improved in industrial fermentations by reducing the heterogeneity within the culture.
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