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Zhou X, Li Z, Chen K, Wei Y, Cao Z, Yu D. The expansion of oligopeptide transporters in Melampsora larici-populina may reflect its adaptation to a phytoparasitic lifestyle. Gene 2024; 920:148506. [PMID: 38670390 DOI: 10.1016/j.gene.2024.148506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 04/13/2024] [Accepted: 04/23/2024] [Indexed: 04/28/2024]
Abstract
The acquisition of nutrients from host plants by phytopathogenic fungi is critically important for their invasion success. Melampsora larici-populina, an obligate biotrophic pathogenic fungus, causes the poplar leaf rust disease and can severely damage host poplar plants. Previously, we found that oligopeptide transporters (OPTs) have undergone a convergent expansion, which might reflect adaptation to a phytoparasitic lifestyle. Here, we used various methods to evaluate this hypothesis, including conserved motif identification, positive selection signal mining, expression pattern clustering analysis, and neutral selection tests. The motif composition of the five clades in the OPT family differed, and positive selection was observed during clade differentiation. This suggests that OPTs in these five clades may be functionally differentiated, which would increase the range of transported substrates and promote the absorption of more types of nitrogen compounds from the hosts. According to clustering analysis of gene expression patterns, the expression of most genes from the two expanded clades (clade 2 and 4) was up-regulated during the infection of poplar trees, indicating that the expansion of OPTs likely occurred to promote the uptake of oligopeptides from host poplar plants. The MellpOPT4g gene was determined to be under significant balancing selection based on the neutral selection tests, suggesting that it plays a role in the pathogenic process. In conclusion, these three observations provide preliminary evidence supporting our hypothesis, as they indicate that the expansion of OPTs in M. larici-populina has aided the ability of this pathogen to acquire nutrients from host plants.
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Affiliation(s)
- Xianzhen Zhou
- College of Forestry, Northwest A&F University, No. 3 Taicheng Road, Yangling, Shaanxi 712100, China.
| | - Ziye Li
- College of Forestry, Northwest A&F University, No. 3 Taicheng Road, Yangling, Shaanxi 712100, China.
| | - Kaiyue Chen
- College of Forestry, Northwest A&F University, No. 3 Taicheng Road, Yangling, Shaanxi 712100, China.
| | - Yefan Wei
- College of Forestry, Northwest A&F University, No. 3 Taicheng Road, Yangling, Shaanxi 712100, China.
| | - Zhimin Cao
- College of Forestry, Northwest A&F University, No. 3 Taicheng Road, Yangling, Shaanxi 712100, China.
| | - Dan Yu
- College of Forestry, Northwest A&F University, No. 3 Taicheng Road, Yangling, Shaanxi 712100, China.
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2
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Guerillot P, Salamov A, Louet C, Morin E, Frey P, Grigoriev IV, Duplessis S. A Remarkable Expansion of Oligopeptide Transporter Genes in Rust Fungi (Pucciniales) Suggests a Specialization in Nutrient Acquisition for Obligate Biotrophy. PHYTOPATHOLOGY 2023; 113:252-264. [PMID: 36044359 DOI: 10.1094/phyto-04-22-0128-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Nutrient acquisition by rust fungi during their biotrophic growth has been assigned to a few transporters expressed in haustorial infection structures. We performed a comparative genomic analysis of all transporter genes (hereafter termed transportome) classified according to the Transporter Classification Database, focusing specifically on rust fungi (order Pucciniales) versus other species in the Dikarya. We also surveyed expression of transporter genes in the poplar rust fungus for which transcriptomics data are available across the whole life cycle. Despite a significant increase in gene number, rust fungi presented a reduced transportome compared with most fungi in the Dikarya. However, a few transporter families in the subclass Porters showed significant expansions. Notably, three metal transport-related families involved in the import, export, and sequestration of metals were expanded in Pucciniales and expressed at various stages of the rust life cycle, suggesting a tight regulation of metal homeostasis. The most remarkable gene expansion in the Pucciniales was observed for the oligopeptide transporter (OPT) family, with 25 genes on average compared with seven to 14 genes in the other surveyed taxonomical ranks. A phylogenetic analysis showed several specific expansion events at the root of the order Pucciniales with subsequent expansions in rust taxonomical families. The OPT genes showed dynamic expression patterns along the rust life cycle and more particularly during infection of the poplar host tree, suggesting a possible specialization for the acquisition of nitrogen and sulfur through the transport of oligopeptides from the host during biotrophic growth.
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Affiliation(s)
- Pamela Guerillot
- Université de Lorraine, INRAE, UMR 1136 IAM, 54000 Nancy, France
| | - Asaf Salamov
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, U.S.A
| | - Clémentine Louet
- Université de Lorraine, INRAE, UMR 1136 IAM, 54000 Nancy, France
| | - Emmanuelle Morin
- Université de Lorraine, INRAE, UMR 1136 IAM, 54000 Nancy, France
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, U.S.A
| | - Pascal Frey
- Université de Lorraine, INRAE, UMR 1136 IAM, 54000 Nancy, France
| | - Igor V Grigoriev
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, U.S.A
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, CA, U.S.A
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3
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Jing Y, Mu C, Wang H, Shen J, Zoetendal EG, Zhu W. Amino acid utilization allows intestinal dominance of Lactobacillus amylovorus. THE ISME JOURNAL 2022; 16:2491-2502. [PMID: 35896730 PMCID: PMC9561148 DOI: 10.1038/s41396-022-01287-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 06/25/2022] [Accepted: 07/05/2022] [Indexed: 06/15/2023]
Abstract
The mammalian intestine harbors heterogeneous distribution of microbes among which specific taxa (e.g. Lactobacillus) dominate across mammals. Deterministic factors such as nutrient availability and utilization may affect microbial distributions. Due to physiological complexity, mechanisms linking nutrient utilization and the dominance of key taxa remain unclear. Lactobacillus amylovorus is a predominant species in the small intestine of pigs. Employing a pig model, we found that the small intestine was dominated by Lactobacillus and particularly L. amylovorus, and enriched with peptide-bound amino acids (PBAAs), all of which were further boosted after a peptide-rich diet. To investigate the bacterial growth dominance mechanism, a representative strain L. amylovorus S1 was isolated from the small intestine and anaerobically cultured in media with free amino acids or peptides as sole nitrogen sources. L. amylovorus S1 grew preferentially with peptide-rich rather than amino acid-rich substrates, as reflected by enhanced growth and PBAA utilization, and peptide transporter upregulations. Utilization of free amino acids (e.g. methionine, valine, lysine) and expressions of transporters and metabolic enzymes were enhanced simultaneously in peptide-rich substrate. Additionally, lactate was elevated in peptide-rich substrates while acetate in amino acid-rich substrates, indicating distinct metabolic patterns depending on substrate forms. These results suggest that an increased capability of utilizing PBAAs contributes to the dominance of L. amylovorus, indicating amino acid utilization as a deterministic factor affecting intestinal microbial distribution. These findings may provide new insights into the microbe-gut nutrition interplay and guidelines for dietary manipulations toward gut health especially small intestine health.
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Affiliation(s)
- Yujia Jing
- Laboratory of Gastrointestinal Microbiology, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
- National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing, 210095, China
| | - Chunlong Mu
- Laboratory of Gastrointestinal Microbiology, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
- National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing, 210095, China
| | - Huisong Wang
- Laboratory of Gastrointestinal Microbiology, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
- National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing, 210095, China
| | - Junhua Shen
- Laboratory of Gastrointestinal Microbiology, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
- National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing, 210095, China
| | - Erwin G Zoetendal
- Laboratory of Gastrointestinal Microbiology, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
- National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing, 210095, China
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Weiyun Zhu
- Laboratory of Gastrointestinal Microbiology, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China.
- National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing, 210095, China.
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4
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Turning Inside Out: Filamentous Fungal Secretion and Its Applications in Biotechnology, Agriculture, and the Clinic. J Fungi (Basel) 2021; 7:jof7070535. [PMID: 34356914 PMCID: PMC8307877 DOI: 10.3390/jof7070535] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/14/2021] [Accepted: 06/25/2021] [Indexed: 12/15/2022] Open
Abstract
Filamentous fungi are found in virtually every marine and terrestrial habitat. Vital to this success is their ability to secrete a diverse range of molecules, including hydrolytic enzymes, organic acids, and small molecular weight natural products. Industrial biotechnologists have successfully harnessed and re-engineered the secretory capacity of dozens of filamentous fungal species to make a diverse portfolio of useful molecules. The study of fungal secretion outside fermenters, e.g., during host infection or in mixed microbial communities, has also led to the development of novel and emerging technological breakthroughs, ranging from ultra-sensitive biosensors of fungal disease to the efficient bioremediation of polluted environments. In this review, we consider filamentous fungal secretion across multiple disciplinary boundaries (e.g., white, green, and red biotechnology) and product classes (protein, organic acid, and secondary metabolite). We summarize the mechanistic understanding for how various molecules are secreted and present numerous applications for extracellular products. Additionally, we discuss how the control of secretory pathways and the polar growth of filamentous hyphae can be utilized in diverse settings, including industrial biotechnology, agriculture, and the clinic.
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Tanaka M, Gomi K. Induction and Repression of Hydrolase Genes in Aspergillus oryzae. Front Microbiol 2021; 12:677603. [PMID: 34108952 PMCID: PMC8180590 DOI: 10.3389/fmicb.2021.677603] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 04/26/2021] [Indexed: 11/13/2022] Open
Abstract
The filamentous fungus Aspergillus oryzae, also known as yellow koji mold, produces high levels of hydrolases such as amylolytic and proteolytic enzymes. This property of producing large amounts of hydrolases is one of the reasons why A. oryzae has been used in the production of traditional Japanese fermented foods and beverages. A wide variety of hydrolases produced by A. oryzae have been used in the food industry. The expression of hydrolase genes is induced by the presence of certain substrates, and various transcription factors that regulate such expression have been identified. In contrast, in the presence of glucose, the expression of the glycosyl hydrolase gene is generally repressed by carbon catabolite repression (CCR), which is mediated by the transcription factor CreA and ubiquitination/deubiquitination factors. In this review, we present the current knowledge on the regulation of hydrolase gene expression, including CCR, in A. oryzae.
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Affiliation(s)
- Mizuki Tanaka
- Biomolecular Engineering Laboratory, School of Food and Nutritional Science, University of Shizuoka, Shizuoka, Japan
| | - Katsuya Gomi
- Laboratory of Fermentation Microbiology, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
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6
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Bertuzzi M, van Rhijn N, Krappmann S, Bowyer P, Bromley MJ, Bignell EM. On the lineage of Aspergillus fumigatus isolates in common laboratory use. Med Mycol 2021; 59:7-13. [PMID: 32944768 PMCID: PMC7779236 DOI: 10.1093/mmy/myaa075] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 08/03/2020] [Accepted: 09/14/2020] [Indexed: 12/12/2022] Open
Abstract
The origin of isolates routinely used by the community of Aspergillus fumigatus researchers is periodically a matter of intense discussion at our centre, as the construction of recombinant isolates have sometimes followed convoluted routes, the documentation describing their lineages is fragmented, and the nomenclature is confusing. As an aide memoir, not least for our own benefit, we submit the following account and tabulated list of strains (Table 1) in an effort to collate all of the relevant information in a single, easily accessible document. To maximise the accuracy of this record we have consulted widely amongst the community of Medical Mycologists using these strains. All the strains described are currently available from one of these organisations, namely the Fungal Genetics Stock Centre (FGSC), FungiDB, Ensembl Fungi and The National Collection of Pathogenic Fungi (NCPF) at Public Health England. Display items from this manuscript are also featured on FungiDB. LAY ABSTRACT We present a concise overview on the definition, origin and unique genetic makeup of the Aspergillus fumigatus isolates routinely in use by the fungal research community, to aid researchers to describe past and new strains and the experimental differences observed more accurately.
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Affiliation(s)
- Margherita Bertuzzi
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Core Technology Facility, Manchester, UK
- Lydia Becker Institute of Immunology and Inflammation, Biology, Medicine and Health. The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Norman van Rhijn
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Core Technology Facility, Manchester, UK
- Lydia Becker Institute of Immunology and Inflammation, Biology, Medicine and Health. The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Sven Krappmann
- Institute of Clinical Microbiology, Immunology and Hygiene, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nürnberg, Germany
| | - Paul Bowyer
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Core Technology Facility, Manchester, UK
- Lydia Becker Institute of Immunology and Inflammation, Biology, Medicine and Health. The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Michael J Bromley
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Core Technology Facility, Manchester, UK
- Lydia Becker Institute of Immunology and Inflammation, Biology, Medicine and Health. The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Elaine M Bignell
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Core Technology Facility, Manchester, UK
- Lydia Becker Institute of Immunology and Inflammation, Biology, Medicine and Health. The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
- MRC Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
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7
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Tanaka M, Ito K, Matsuura T, Kawarasaki Y, Gomi K. Identification and distinct regulation of three di/tripeptide transporters in Aspergillus oryzae. Biosci Biotechnol Biochem 2020; 85:452-463. [DOI: 10.1093/bbb/zbaa030] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 08/26/2020] [Indexed: 12/24/2022]
Abstract
ABSTRACT
The uptake of di/tripeptides is mediated by the proton-dependent oligopeptide transporter (POT) family. In this study, 3 POT family transporters, designated PotA, PotB, and PotC were identified in Aspergillus oryzae. Growth comparison of deletion mutants of these transporter genes suggested that PotB and PotC are responsible for di/tripeptide uptake. PotA, which had the highest sequence similarity to yeast POT (Ptr2), contributed little to the uptake. Nitrogen starvation induced potB and potC expression, but not potA expression. When 3 dipeptides were provided as nitrogen sources, the expression profiles of these genes were different. PrtR, a transcription factor that regulates proteolytic genes, was involved in regulation of potA and potB but not in potC expression. Only potC expression levels were dramatically reduced by disruption of ubrA, an orthologue of yeast ubiquitin ligase UBR1 responsible for PTR2 expression. Expression of individual POT genes is apparently controlled by different regulatory mechanisms.
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Affiliation(s)
- Mizuki Tanaka
- Biomolecular Engineering Laboratory, School of Food and Nutritional Science, University of Shizuoka, Suruga-ku, Shizuoka, Japan
| | - Keisuke Ito
- Laboratory of Food Chemistry, School of Food and Nutritional Science, University of Shizuoka, Suruga-ku, Shizuoka, Japan
| | - Tomomi Matsuura
- Laboratory of Bioindustrial Genomics, Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai, Japan
| | - Yasuaki Kawarasaki
- Biomolecular Engineering Laboratory, School of Food and Nutritional Science, University of Shizuoka, Suruga-ku, Shizuoka, Japan
| | - Katsuya Gomi
- Laboratory of Bioindustrial Genomics, Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai, Japan
- Laboratory of Fermentation Microbiology, Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai, Japan
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8
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The Aspergillus fumigatus Phosphoproteome Reveals Roles of High-Osmolarity Glycerol Mitogen-Activated Protein Kinases in Promoting Cell Wall Damage and Caspofungin Tolerance. mBio 2020; 11:mBio.02962-19. [PMID: 32019798 PMCID: PMC7002344 DOI: 10.1128/mbio.02962-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Aspergillus fumigatus is an opportunistic human pathogen causing allergic reactions or systemic infections, such as invasive pulmonary aspergillosis in immunocompromised patients. The mitogen-activated protein kinase (MAPK) signaling pathways are essential for fungal adaptation to the human host. Fungal cell survival, fungicide tolerance, and virulence are highly dependent on the organization, composition, and function of the cell wall. Upon cell wall stress, MAPKs phosphorylate multiple target proteins involved in the remodeling of the cell wall. Here, we investigate the global phosphoproteome of the ΔsakA and ΔmpkCA. fumigatus and high-osmolarity glycerol (HOG) pathway MAPK mutants upon cell wall damage. This showed the involvement of the HOG pathway and identified novel protein kinases and transcription factors, which were confirmed by fungal genetics to be involved in promoting tolerance of cell wall damage. Our results provide understanding of how fungal signal transduction networks modulate the cell wall. This may also lead to the discovery of new fungicide drug targets to impact fungal cell wall function, fungicide tolerance, and virulence. The filamentous fungus Aspergillus fumigatus can cause a distinct set of clinical disorders in humans. Invasive aspergillosis (IA) is the most common life-threatening fungal disease of immunocompromised humans. The mitogen-activated protein kinase (MAPK) signaling pathways are essential to the adaptation to the human host. Fungal cell survival is highly dependent on the organization, composition, and function of the cell wall. Here, an evaluation of the global A. fumigatus phosphoproteome under cell wall stress caused by the cell wall-damaging agent Congo red (CR) revealed 485 proteins potentially involved in the cell wall damage response. Comparative phosphoproteome analyses with the ΔsakA, ΔmpkC, and ΔsakA ΔmpkC mutant strains from the osmotic stress MAPK cascades identify their additional roles during the cell wall stress response. Our phosphoproteomics allowed the identification of novel kinases and transcription factors (TFs) involved in osmotic stress and in the cell wall integrity (CWI) pathway. Our global phosphoproteome network analysis showed an enrichment for protein kinases, RNA recognition motif domains, and the MAPK signaling pathway. In contrast to the wild-type strain, there is an overall decrease of differentially phosphorylated kinases and phosphatases in ΔsakA, ΔmpkC, and ΔsakA ΔmpkC mutants. We constructed phosphomutants for the phosphorylation sites of several proteins differentially phosphorylated in the wild-type and mutant strains. For all the phosphomutants, there is an increase in the sensitivity to cell wall-damaging agents and a reduction in the MpkA phosphorylation upon CR stress, suggesting these phosphosites could be important for the MpkA modulation and CWI pathway regulation.
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Xie XL, Wei Y, Song YY, Pan GM, Chen LN, Wang G, Zhang SH. Genetic Analysis of Four Sexual Differentiation Process Proteins (isp4/SDPs) in Chaetomium thermophilum and Thermomyces lanuginosus Reveals Their Distinct Roles in Development. Front Microbiol 2020; 10:2994. [PMID: 31969873 PMCID: PMC6956688 DOI: 10.3389/fmicb.2019.02994] [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: 10/22/2019] [Accepted: 12/10/2019] [Indexed: 12/29/2022] Open
Abstract
Fungal sexual development requires the involvement of a large number of functional genes. Fungal genes encoding sexual differentiation process proteins (SDPs), isps, have been known for decades. isp4/SDP and its homologs function as oligopeptide transporters (OPTs), yet their roles in reproduction are unknown. Here, we genetically analyzed all four isp4/SDP homologs in the sexual species Chaetomium thermophilum and asexual species Thermomyces lanuginosus. Using single gene deletion mutants, we found that T. lanuginosus SDP (TlSDP) participated in asexual sporulation, whereas the other homologs participated in sexual morphogenesis. In complementary tests, C. thermophilum SDPs (CtSDP1-3) restored sporulation defects in TlSDP deletion strains (ΔTlSDP), and their translated proteins, which were localized onto the cytomembrane, possessed OPT activity. Interestingly, CtSDP2 accumulated at the top of the hyphae played a distinct role in determining the sexual cycle, glutathione transport, and lifespan shortening. A unique 72nt-insertion fragment (72INS) was discovered in CtSDP2. Biological analysis of the 72INS deletion and DsRED-tagged fusion strains implied the involvement of 72INS in fungal growth and development. In contrast to TlSDP, which only contributes to conidial production, the three CtSDPs play important roles in sexual and asexual reproduction, and CtSDP2 harbors a unique functional 72INS that initiates sexual morphogenesis.
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Affiliation(s)
- Xiang-Li Xie
- College of Plant Sciences, Jilin University, Changchun, China
| | - Yi Wei
- College of Plant Sciences, Jilin University, Changchun, China
| | - Yan-Yue Song
- College of Plant Sciences, Jilin University, Changchun, China
| | - Guan-Ming Pan
- College of Plant Sciences, Jilin University, Changchun, China
| | - Li-Na Chen
- College of Plant Sciences, Jilin University, Changchun, China
| | - Gang Wang
- School of Life Sciences, Henan University, Kaifeng, China
| | - Shi-Hong Zhang
- College of Plant Sciences, Jilin University, Changchun, China
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10
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Role of Amino Acid Metabolism in the Virulence of Human Pathogenic Fungi. CURRENT CLINICAL MICROBIOLOGY REPORTS 2019. [DOI: 10.1007/s40588-019-00124-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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11
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Liu XH, Zhao JF, Wang T, Wu MB. Design, identification, antifungal evaluation and molecular modeling of chlorotetaine derivatives as new anti-fungal agents. Nat Prod Res 2018; 34:1712-1720. [PMID: 30417659 DOI: 10.1080/14786419.2018.1528582] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
It is feasible to rationally modify existing bioactive components for new drug development, achieving molecules with improved biological activities. In this study, rational modification of chlorotetaine was carried out following in silico molecular modelling to enhance interactions between the fungal oligopeptide transmembrane transporter PTR22 and the ligand. The peptide obtained with the lowest docking energy, Lys-chlorotetaine (LC), displayed an improved antifungal effect compared with chlorotetaine. The lowest minimum inhibitory concentration observed against a tested pathogen was 1.47 µg/mL (Candida krusei CBS573), which was satisfactory. To thoroughly explore the detailed interactions between the transporter and LC, molecular dynamics simulation was also performed, which revealed that LC could bind to the transporter via different intermolecular interactions from chlorotetaine, and predicted electrostatic interactions (salt-bridges) would enable the more efficient release of LC. This study provides a simple and reliable method for the rational modification of oligopeptide antibiotics.
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Affiliation(s)
- Xiao Huan Liu
- School of Biological Science, Jining Medical University, Jining, China
| | - Jiong Feng Zhao
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, China
| | - Tao Wang
- School of Biological Science, Jining Medical University, Jining, China.,Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, China
| | - Mian Bin Wu
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, China.,Zhejiang Key Laboratory of Antifungal Drugs, Taizhou, China
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12
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Shende R, Wong SSW, Rapole S, Beau R, Ibrahim-Granet O, Monod M, Gührs KH, Pal JK, Latgé JP, Madan T, Aimanianda V, Sahu A. Aspergillus fumigatus conidial metalloprotease Mep1p cleaves host complement proteins. J Biol Chem 2018; 293:15538-15555. [PMID: 30139746 PMCID: PMC6177592 DOI: 10.1074/jbc.ra117.001476] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 08/02/2018] [Indexed: 12/30/2022] Open
Abstract
Innate immunity in animals including humans encompasses the complement system, which is considered an important host defense mechanism against Aspergillus fumigatus, one of the most ubiquitous opportunistic human fungal pathogens. Previously, it has been shown that the alkaline protease Alp1p secreted from A. fumigatus mycelia degrades the complement components C3, C4, and C5. However, it remains unclear how the fungal spores (i.e. conidia) defend themselves against the activities of the complement system immediately after inhalation into the lung. Here, we show that A. fumigatus conidia contain a metalloprotease Mep1p, which is released upon conidial contact with collagen and inactivates all three complement pathways. In particular, Mep1p efficiently inactivated the major complement components C3, C4, and C5 and their activation products (C3a, C4a, and C5a) as well as the pattern-recognition molecules MBL and ficolin-1, either by directly cleaving them or by cleaving them to a form that is further broken down by other proteases of the complement system. Moreover, incubation of Mep1p with human serum significantly inhibited the complement hemolytic activity and conidial opsonization by C3b and their subsequent phagocytosis by macrophages. Together, these results indicate that Mep1p associated with and released from A. fumigatus conidia likely facilitates early immune evasion by disarming the complement defense in the human host.
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Affiliation(s)
- Rajashri Shende
- From the Complement Biology Laboratory and
- the Dr. D. Y. Patil Biotechnology and Bioinformatics Institute, Dr. D. Y. Patil Vidyapeeth, Tathawade, Pune-411033, India
| | | | - Srikanth Rapole
- Proteomics Laboratory, National Centre for Cell Science, S. P. Pune University Campus, Ganeshkhind, Pune-411007, India
| | | | | | - Michel Monod
- the Service de Dermatologie, Laboratoire de Mycologie, Centre Hospitalier Universitaire Vaudois, 1011 Lausanne, Switzerland
| | - Karl-Heinz Gührs
- the Leibniz Institute on Aging-Fritz Lipmann Institute, Jena-07745, Germany, and
| | - Jayanta Kumar Pal
- the Dr. D. Y. Patil Biotechnology and Bioinformatics Institute, Dr. D. Y. Patil Vidyapeeth, Tathawade, Pune-411033, India
| | | | - Taruna Madan
- the ICMR-National Institute for Research in Reproductive Health, Parel, Mumbai-400012, India
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13
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Geißel B, Loiko V, Klugherz I, Zhu Z, Wagener N, Kurzai O, van den Hondel CAMJJ, Wagener J. Azole-induced cell wall carbohydrate patches kill Aspergillus fumigatus. Nat Commun 2018; 9:3098. [PMID: 30082817 PMCID: PMC6078979 DOI: 10.1038/s41467-018-05497-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 07/02/2018] [Indexed: 11/26/2022] Open
Abstract
Azole antifungals inhibit the fungal ergosterol biosynthesis pathway, resulting in either growth inhibition or killing of the pathogen, depending on the species. Here we report that azoles have an initial growth-inhibitory (fungistatic) activity against the pathogen Aspergillus fumigatus that can be separated from the succeeding fungicidal effects. At a later stage, the cell wall salvage system is induced. This correlates with successive cell integrity loss and death of hyphal compartments. Time-lapse fluorescence microscopy reveals excessive synthesis of cell wall carbohydrates at defined spots along the hyphae, leading to formation of membrane invaginations and eventually rupture of the plasma membrane. Inhibition of β-1,3-glucan synthesis reduces the formation of cell wall carbohydrate patches and delays cell integrity failure and fungal death. We propose that azole antifungals exert their fungicidal activity by triggering synthesis of cell wall carbohydrate patches that penetrate the plasma membrane, thereby killing the fungus. The elucidated mechanism may be potentially exploited as a novel approach for azole susceptibility testing. Azole antifungals inhibit fungal ergosterol biosynthesis. Here, Geißel et al. show that the fungicidal activity of azoles involves excessive synthesis of cell wall carbohydrates at defined spots along the hyphae, leading to formation of membrane invaginations and eventually rupture of the plasma membrane.
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Affiliation(s)
- Bernadette Geißel
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Medizinische Fakultät, LMU München, Pettenkoferstraße 9a, 80336, Munich, Germany
| | - Veronika Loiko
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Medizinische Fakultät, LMU München, Pettenkoferstraße 9a, 80336, Munich, Germany
| | - Isabel Klugherz
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Medizinische Fakultät, LMU München, Pettenkoferstraße 9a, 80336, Munich, Germany
| | - Zhaojun Zhu
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Medizinische Fakultät, LMU München, Pettenkoferstraße 9a, 80336, Munich, Germany
| | - Nikola Wagener
- Zell- und Entwicklungsbiologie, Department Biologie II, LMU München, Großhaderner Straße 2, 82152, Planegg-Martinsried, Germany
| | - Oliver Kurzai
- Institut für Hygiene und Mikrobiologie, Julius-Maximilians-Universität Würzburg, Josef-Schneider-Straße 2, 97080, Würzburg, Germany.,National Reference Center for Invasive Fungal Infections (NRZMyk), Leibniz-Institut für Naturstoff-Forschung und Infektionsbiologie, Hans-Knöll-Institut, Adolf-Reichwein-Straße 23, 07745, Jena, Germany
| | - Cees A M J J van den Hondel
- Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands
| | - Johannes Wagener
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Medizinische Fakultät, LMU München, Pettenkoferstraße 9a, 80336, Munich, Germany. .,Institut für Hygiene und Mikrobiologie, Julius-Maximilians-Universität Würzburg, Josef-Schneider-Straße 2, 97080, Würzburg, Germany. .,National Reference Center for Invasive Fungal Infections (NRZMyk), Leibniz-Institut für Naturstoff-Forschung und Infektionsbiologie, Hans-Knöll-Institut, Adolf-Reichwein-Straße 23, 07745, Jena, Germany.
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14
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Shemesh E, Hanf B, Hagag S, Attias S, Shadkchan Y, Fichtman B, Harel A, Krüger T, Brakhage AA, Kniemeyer O, Osherov N. Phenotypic and Proteomic Analysis of the Aspergillus fumigatus Δ PrtT, Δ XprG and Δ XprG/Δ PrtT Protease-Deficient Mutants. Front Microbiol 2017; 8:2490. [PMID: 29312198 PMCID: PMC5732999 DOI: 10.3389/fmicb.2017.02490] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Accepted: 11/30/2017] [Indexed: 11/13/2022] Open
Abstract
Aspergillus fumigatus is the most common mold species to cause disease in immunocompromised patients. Infection usually begins when its spores (conidia) are inhaled into the airways, where they germinate, forming hyphae that penetrate and destroy the lungs and disseminate to other organs, leading to high mortality. The ability of hyphae to penetrate the pulmonary epithelium is a key step in the infectious process. A. fumigatus produces extracellular proteases that are thought to enhance penetration by degrading host structural barriers. This study explores the role of the A. fumigatus transcription factor XprG in controlling secreted proteolytic activity and fungal virulence. We deleted xprG, alone and in combination with prtT, a transcription factor previously shown to regulate extracellular proteolysis. xprG deletion resulted in abnormal conidiogenesis and formation of lighter colored, more fragile conidia and a moderate reduction in the ability of culture filtrates (CFs) to degrade substrate proteins. Deletion of both xprG and prtT resulted in an additive reduction, generating a mutant strain producing CF with almost no ability to degrade substrate proteins. Detailed proteomic analysis identified numerous secreted proteases regulated by XprG and PrtT, alone and in combination. Interestingly, proteomics also identified reduced levels of secreted cell wall modifying enzymes (glucanases, chitinases) and allergens following deletion of these genes, suggesting they target additional cellular processes. Surprisingly, despite the major alteration in the secretome of the xprG/prtT null mutant, including two to fivefold reductions in the level of 24 proteases, 18 glucanases, 6 chitinases, and 19 allergens, it retained wild-type virulence in murine systemic and pulmonary models of infection. This study highlights the extreme adaptability of A. fumigatus during infection based on extensive gene redundancy.
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Affiliation(s)
- Einav Shemesh
- Aspergillus and Antifungal Research Laboratory, Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Benjamin Hanf
- Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI), Jena, Germany.,Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Shelly Hagag
- Aspergillus and Antifungal Research Laboratory, Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Shani Attias
- Aspergillus and Antifungal Research Laboratory, Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yana Shadkchan
- Aspergillus and Antifungal Research Laboratory, Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Boris Fichtman
- Faculty of Medicine in the Galilee, Bar-Ilan University, Safed, Israel
| | - Amnon Harel
- Faculty of Medicine in the Galilee, Bar-Ilan University, Safed, Israel
| | - Thomas Krüger
- Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI), Jena, Germany.,Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Axel A Brakhage
- Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI), Jena, Germany.,Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Olaf Kniemeyer
- Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI), Jena, Germany.,Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Nir Osherov
- Aspergillus and Antifungal Research Laboratory, Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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15
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Xiang Q, Shen K, Yu X, Zhao K, Gu Y, Zhang X, Chen X, Chen Q. Analysis of the oligopeptide transporter gene family in Ganoderma lucidum: structure, phylogeny, and expression patterns. Genome 2017; 60:293-302. [DOI: 10.1139/gen-2016-0120] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Oligopeptide transporters (OPTs) are believed to transport broad ranges of substrates across the plasma membrane from the extracellular environment into the cell and are thought to contribute to various biological processes. In the present study, 13 putative OPTs (Gl-OPT1 to Gl-OPT13) were identified through extensive search of Ganoderma lucidum genome database. Phylogenetic analysis with OPTs from other fungi and plants indicates that these genes can be further divided into five groups. Motif compositions of OPT members are highly conserved in each group, indicative of functional conservation. Expression profile analysis of the 13 Gl-OPT genes indicated that, with the exception of Gl-OPT7–Gl-OPT9, for which no transcripts were detected, all paralogues were differentially expressed, suggesting their potential involvement in stress response and functional development of fungi. Overall, the analyses in this study provide a starting point for elucidating the functions of OPT in G. lucidum, and for understanding the complexities of metabolic regulation.
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Affiliation(s)
- Quanju Xiang
- College of Resource, Sichuan Agricultural University, Chengdu 611130, Sichuan, China
| | - Keyu Shen
- College of Resource, Sichuan Agricultural University, Chengdu 611130, Sichuan, China
| | - Xiumei Yu
- College of Resource, Sichuan Agricultural University, Chengdu 611130, Sichuan, China
| | - Ke Zhao
- College of Resource, Sichuan Agricultural University, Chengdu 611130, Sichuan, China
| | - Yunfu Gu
- College of Resource, Sichuan Agricultural University, Chengdu 611130, Sichuan, China
| | - Xiaoping Zhang
- College of Resource, Sichuan Agricultural University, Chengdu 611130, Sichuan, China
| | - Xiaoqiong Chen
- Rice Research Institute of Sichuan Agricultural University, Chengdu 611130, Sichuan, China
| | - Qiang Chen
- College of Resource, Sichuan Agricultural University, Chengdu 611130, Sichuan, China
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16
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Exploration of Sulfur Assimilation of Aspergillus fumigatus Reveals Biosynthesis of Sulfur-Containing Amino Acids as a Virulence Determinant. Infect Immun 2016; 84:917-929. [PMID: 26787716 DOI: 10.1128/iai.01124-15] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 01/07/2016] [Indexed: 12/17/2022] Open
Abstract
Fungal infections are of major relevance due to the increased numbers of immunocompromised patients, frequently delayed diagnosis, and limited therapeutics. To date, the growth and nutritional requirements of fungi during infection, which are relevant for invasion of the host, are poorly understood. This is particularly true for invasive pulmonary aspergillosis, as so far, sources of (macro)elements that are exploited during infection have been identified to only a limited extent. Here, we have investigated sulfur (S) utilization by the human-pathogenic mold Aspergillus fumigatus during invasive growth. Our data reveal that inorganic S compounds or taurine is unlikely to serve as an S source during invasive pulmonary aspergillosis since a sulfate transporter mutant strain and a sulfite reductase mutant strain are fully virulent. In contrast, the S-containing amino acid cysteine is limiting for fungal growth, as proven by the reduced virulence of a cysteine auxotroph. Moreover, phenotypic characterization of this strain further revealed the robustness of the subordinate glutathione redox system. Interestingly, we demonstrate that methionine synthase is essential for A. fumigatus virulence, defining the biosynthetic route of this proteinogenic amino acid as a potential antifungal target. In conclusion, we provide novel insights into the nutritional requirements ofA. fumigatus during pathogenesis, a prerequisite to understanding and fighting infection.
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17
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Maeda H, Sakai D, Kobayashi T, Morita H, Okamoto A, Takeuchi M, Kusumoto KI, Amano H, Ishida H, Yamagata Y. Three extracellular dipeptidyl peptidases found in Aspergillus oryzae show varying substrate specificities. Appl Microbiol Biotechnol 2016; 100:4947-58. [PMID: 26846741 DOI: 10.1007/s00253-016-7339-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 01/14/2016] [Accepted: 01/17/2016] [Indexed: 02/04/2023]
Abstract
Three extracellular dipeptidyl peptidase genes, dppB, dppE, and dppF, were unveiled by sequence analysis of the Aspergillus oryzae genome. We investigated their differential enzymatic profiles, in order to gain an understanding of the diversity of these genes. The three dipeptidyl peptidases were expressed using Aspergillus nidulans as the host. Each recombinant enzyme was purified and subsequently characterized. The enzymes displayed similar optimum pH values, but optimum temperatures, pH stabilities, and substrate specificities varied. DppB was identified as a Xaa-Prolyl dipeptidyl peptidase, while DppE scissile substrates were similar to the substrates for Aspergillus fumigatus DPPV (AfDPPV). DppF was found to be a novel enzyme that could digest both substrates for A. fumigatus DPPIV and AfDPPV. Semi-quantitative PCR revealed that the transcription of dppB in A. oryzae was induced by protein substrates and repressed by the addition of an inorganic nitrogen source, despite the presence of protein substrates. The transcription of dppE depended on its growth time, while the transcription of dppF was not affected by the type of the nitrogen source in the medium, and it started during the early stage of the fungal growth. Based on these results, we conclude that these enzymes may represent the nutrition acquisition enzymes. Additionally, DppF may be one of the sensor peptidases responsible for the detection of the protein substrates in A. oryzae environment. DppB may be involved in nitrogen assimilation control, since the transcription of dppB was repressed by NaNO3, despite the presence of protein substrates.
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Affiliation(s)
- Hiroshi Maeda
- Department of Applied Molecular Biology and Biochemistry, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, 1838509, Japan
| | - Daisuke Sakai
- Department of Applied Molecular Biology and Biochemistry, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, 1838509, Japan
| | - Takuji Kobayashi
- Department of Applied Molecular Biology and Biochemistry, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, 1838509, Japan
| | - Hiroto Morita
- Department of Applied Molecular Biology and Biochemistry, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, 1838509, Japan
- Microbiology & Fermentation Laboratory, CALPIS Co. Ltd. 5-11-10 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 2520206, Japan
| | - Ayako Okamoto
- Department of Applied Molecular Biology and Biochemistry, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, 1838509, Japan
| | - Michio Takeuchi
- Department of Applied Molecular Biology and Biochemistry, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, 1838509, Japan
| | - Ken-Ichi Kusumoto
- National Food Research Institute, 2-1-12 Kan-nondai, Tsukuba, Ibaraki, 3058642, Japan
| | - Hitoshi Amano
- Amano Enzyme Inc., 1-2-7 Nishiki, Naka-ku, Nagoya, Aichi, 4608630, Japan
| | - Hiroki Ishida
- Gekkeikan Sake Co., Ltd., 247 Minamihama-cho, Fushimi-ku, Kyoto, 6128660, Japan
| | - Youhei Yamagata
- Department of Applied Molecular Biology and Biochemistry, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, 1838509, Japan.
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18
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Funk J, Schaarschmidt B, Slesiona S, Hallström T, Horn U, Brock M. The glycolytic enzyme enolase represents a plasminogen-binding protein on the surface of a wide variety of medically important fungal species. Int J Med Microbiol 2015; 306:59-68. [PMID: 26679571 DOI: 10.1016/j.ijmm.2015.11.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 10/27/2015] [Accepted: 11/29/2015] [Indexed: 11/26/2022] Open
Abstract
Allergies are an increasing issue in human health and can, eventually, cause severe anaphylactic shock. Aspergillus fumigatus and Candida albicans are leading causes of life-threatening invasive fungal infections in immunocompromised patients, but can also cause severe allergic responses in otherwise healthy individuals. The glycolytic enzyme enolase is known as a major allergen despite its function in intracellular metabolism. Therefore, its presentation on surfaces of different fungal species was investigated by using antibodies raised against recombinant enolases from A. fumigatus and C. albicans. Examination of antibody specificity revealed cross-reactivity to cell-free extracts from Aspergillus terreus, Aspergillus flavus, Aspergillus nidulans and Candida glabrata, but not against any of the three human enolases. Antibody specificity was further confirmed by hybridization with other recombinant fungal enolases, where the antibodies recognized different subsets of fungal enolases. When surface presentation of enolase was tested on intact fungal cells, a positive staining was obtained with those antibodies that also recognized the enzyme from the respective cell-free extract. This implies a general surface presentation of this glycolytic enzyme among fungal species and provides hints for its predominant recognition as an allergen. Additionally, A. fumigatus and C. albicans enolase bound to human plasminogen, which remained accessible for the plasminogen activator uPA. This implies a potential role of enolase in the invasion and dissemination process during fungal infections.
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Affiliation(s)
- Jana Funk
- Bio Pilot Plant, Leibniz-Institute for Natural Product Research and Infection Biology-Hans-Knöll-Institute (HKI), Beutenbergstr. 11a, 07745, Jena, Germany
| | - Barbara Schaarschmidt
- Bio Pilot Plant, Leibniz-Institute for Natural Product Research and Infection Biology-Hans-Knöll-Institute (HKI), Beutenbergstr. 11a, 07745, Jena, Germany
| | - Silvia Slesiona
- Microbial Immunology, Leibniz-Institute for Natural Product Research and Infection Biology-Hans-Knöll-Institute (HKI), Beutenbergstr. 11a, 07745, Jena, Germany
| | - Teresia Hallström
- Infection Biology, Leibniz-Institute for Natural Product Research and Infection Biology-Hans-Knöll-Institute (HKI), Beutenbergstr. 11a, 07745, Jena, Germany
| | - Uwe Horn
- Bio Pilot Plant, Leibniz-Institute for Natural Product Research and Infection Biology-Hans-Knöll-Institute (HKI), Beutenbergstr. 11a, 07745, Jena, Germany
| | - Matthias Brock
- Microbial Biochemistry and Physiology, Leibniz-Institute for Natural Product Research and Infection Biology-Hans-Knöll-Institute (HKI), Beutenbergstr. 11a, 07745, Jena, Germany; Institute for Microbiology, Friedrich-Schiller-University Jena, 07743, Jena, Germany; Fungal Genetics and Biology Group, School of Life Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
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19
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The pH-responsive PacC transcription factor of Aspergillus fumigatus governs epithelial entry and tissue invasion during pulmonary aspergillosis. PLoS Pathog 2014; 10:e1004413. [PMID: 25329394 PMCID: PMC4199764 DOI: 10.1371/journal.ppat.1004413] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 08/20/2014] [Indexed: 12/29/2022] Open
Abstract
Destruction of the pulmonary epithelium is a major feature of lung diseases caused by the mould pathogen Aspergillus fumigatus. Although it is widely postulated that tissue invasion is governed by fungal proteases, A. fumigatus mutants lacking individual or multiple enzymes remain fully invasive, suggesting a concomitant requirement for other pathogenic activities during host invasion. In this study we discovered, and exploited, a novel, tissue non-invasive, phenotype in A. fumigatus mutants lacking the pH-responsive transcription factor PacC. Our study revealed a novel mode of epithelial entry, occurring in a cell wall-dependent manner prior to protease production, and via the Dectin-1 β-glucan receptor. ΔpacC mutants are defective in both contact-mediated epithelial entry and protease expression, and significantly attenuated for pathogenicity in leukopenic mice. We combined murine infection modelling, in vivo transcriptomics, and in vitro infections of human alveolar epithelia, to delineate two major, and sequentially acting, PacC-dependent processes impacting epithelial integrity in vitro and tissue invasion in the whole animal. We demonstrate that A. fumigatus spores and germlings are internalised by epithelial cells in a contact-, actin-, cell wall- and Dectin-1 dependent manner and ΔpacC mutants, which aberrantly remodel the cell wall during germinative growth, are unable to gain entry into epithelial cells, both in vitro and in vivo. We further show that PacC acts as a global transcriptional regulator of secreted molecules during growth in the leukopenic mammalian lung, and profile the full cohort of secreted gene products expressed during invasive infection. Our study reveals a combinatorial mode of tissue entry dependent upon sequential, and mechanistically distinct, perturbations of the pulmonary epithelium and demonstrates, for the first time a protective role for Dectin-1 blockade in epithelial defences. Infecting ΔpacC mutants are hypersensitive to cell wall-active antifungal agents highlighting the value of PacC signalling as a target for antifungal therapy. Inhaled spores of the pathogenic mould Aspergillus fumigatus cause fungal lung infections in humans having immune defects. A. fumigatus spores germinate within the immunocompromised lung, producing invasively growing, elongated cells called hyphae. Hyphae degrade the surrounding pulmonary tissue, a process thought to be caused by secreted fungal enzymes; however, A. fumigatus mutants lacking one or more protease activities retain fully invasive phenotypes in mouse models of disease. Here we report the first discovery of a non-invasive A. fumigatus mutant, which lacks a pH-responsive transcription factor PacC. Using global transcriptional profiling of wild type and mutant isolates, and in vitro pulmonary invasion assays, we established that loss of PacC leads to a compound non-invasive phenotype characterised by deficits in both contact-mediated epithelial entry and protease expression. Consistent with an important role for epithelial entry in promoting invasive disease in mammalian tissues, PacC mutants remain surface-localised on mammalian epithelia, both in vitro and in vivo. Our study sets a new precedent for involvement of both host and pathogen activities in promoting epithelial invasion by A. fumigatus and supports a model wherein fungal protease activity acting subsequently to, or in parallel with, host-mediated epithelial entry provides the mechanistic basis for tissue invasion.
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20
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O'Keeffe G, Hammel S, Owens RA, Keane TM, Fitzpatrick DA, Jones GW, Doyle S. RNA-seq reveals the pan-transcriptomic impact of attenuating the gliotoxin self-protection mechanism in Aspergillus fumigatus. BMC Genomics 2014; 15:894. [PMID: 25311525 PMCID: PMC4209032 DOI: 10.1186/1471-2164-15-894] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 10/07/2014] [Indexed: 11/21/2022] Open
Abstract
Background Aspergillus fumigatus produces a number of secondary metabolites, one of which, gliotoxin, has been shown to exhibit anti-fungal activity. Thus, A. fumigatus must be able to protect itself against gliotoxin. Indeed one of the genes in the gliotoxin biosynthetic gene cluster in A. fumigatus, gliT, is required for self-protection against the toxin- however the global self-protection mechanism deployed is unclear. RNA-seq was employed to identify genes differentially regulated upon exposure to gliotoxin in A. fumigatus wild-type and A. fumigatus ∆gliT, a strain that is hypersensitive to gliotoxin. Results Deletion of A. fumigatus gliT resulted in altered expression of 208 genes (log2 fold change of 1.5) when compared to A. fumigatus wild-type, of which 175 genes were up-regulated and 33 genes were down-regulated. Expression of 164 genes was differentially regulated (log2 fold change of 1.5) in A. fumigatus wild-type when exposed to gliotoxin, consisting of 101 genes with up-regulated expression and 63 genes with down-regulated expression. Interestingly, a much larger number of genes, 1700, were found to be differentially regulated (log2 fold change of 1.5) in A. fumigatus ∆gliT when challenged with gliotoxin. These consisted of 508 genes with up-regulated expression, and 1192 genes with down-regulated expression. Functional Catalogue (FunCat) classification of differentially regulated genes revealed an enrichment of genes involved in both primary metabolic functions and secondary metabolism. Specifically, genes involved in gliotoxin biosynthesis, helvolic acid biosynthesis, siderophore-iron transport genes and also nitrogen metabolism genes and ribosome biogenesis genes underwent altered expression. It was confirmed that gliotoxin biosynthesis is induced upon exposure to exogenous gliotoxin, production of unrelated secondary metabolites is attenuated in A. fumigatus ∆gliT, while quantitative proteomic analysis confirmed disrupted translation in A. fumigatus ∆gliT challenged with exogenous gliotoxin. Conclusions This study presents the first global investigation of the transcriptional response to exogenous gliotoxin in A. fumigatus wild-type and the hyper-sensitive strain, ∆gliT. Our data highlight the global and extensive affects of exogenous gliotoxin on a sensitive strain devoid of a self-protection mechanism and infer that GliT functionality is required for the optimal biosynthesis of selected secondary metabolites in A. fumigatus. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-894) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | | | - Sean Doyle
- Department of Biology, National University of Ireland Maynooth, Maynooth, Co, Kildare, Ireland.
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21
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Abstract
Fungal pathogens must assimilate local nutrients to establish an infection in their mammalian host. We focus on carbon, nitrogen, and micronutrient assimilation mechanisms, discussing how these influence host-fungus interactions during infection. We highlight several emerging trends based on the available data. First, the perturbation of carbon, nitrogen, or micronutrient assimilation attenuates fungal pathogenicity. Second, the contrasting evolutionary pressures exerted on facultative versus obligatory pathogens have led to contemporary pathogenic fungal species that display differing degrees of metabolic flexibility. The evolutionarily ancient metabolic pathways are conserved in most fungal pathogen, but interesting gaps exist in some species (e.g., Candida glabrata). Third, metabolic flexibility is generally essential for fungal pathogenicity, and in particular, for the adaptation to contrasting host microenvironments such as the gastrointestinal tract, mucosal surfaces, bloodstream, and internal organs. Fourth, this metabolic flexibility relies on complex regulatory networks, some of which are conserved across lineages, whereas others have undergone significant evolutionary rewiring. Fifth, metabolic adaptation affects fungal susceptibility to antifungal drugs and also presents exciting opportunities for the development of novel therapies.
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Affiliation(s)
- Iuliana V Ene
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, 07745 Jena, Germany
| | - Alistair J P Brown
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, 07745 Jena, Germany Friedrich Schiller University, 07743 Jena, Germany Center for Sepsis Control and Care, Universitätsklinikum Jena, 07747 Jena, Germany
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22
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Belmondo S, Fiorilli V, Pérez-Tienda J, Ferrol N, Marmeisse R, Lanfranco L. A dipeptide transporter from the arbuscular mycorrhizal fungus Rhizophagus irregularis is upregulated in the intraradical phase. FRONTIERS IN PLANT SCIENCE 2014; 5:436. [PMID: 25232358 PMCID: PMC4153046 DOI: 10.3389/fpls.2014.00436] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 08/15/2014] [Indexed: 05/09/2023]
Abstract
Arbuscular mycorrhizal fungi (AMF), which form an ancient and widespread mutualistic symbiosis with plants, are a crucial but still enigmatic component of the plant micro biome. Nutrient exchange has probably been at the heart of the success of this plant-fungus interaction since the earliest days of plants on land. To characterize genes from the fungal partner involved in nutrient exchange, and presumably important for the functioning of the AM symbiosis, genome-wide transcriptomic data obtained from the AMF Rhizophagus irregularis were exploited. A gene sequence, showing amino acid sequence and transmembrane domains profile similar to members of the PTR2 family of fungal oligopeptide transporters, was identified and called RiPTR2. The functional properties of RiPTR2 were investigated by means of heterologous expression in Saccharomyces cerevisiae mutants defective in either one or both of its di/tripeptide transporter genes PTR2 and DAL5. These assays showed that RiPTR2 can transport dipeptides such as Ala-Leu, Ala-Tyr or Tyr-Ala. From the gene expression analyses it seems that RiPTR2 responds to different environmental clues when the fungus grows inside the root and in the extraradical phase.
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Affiliation(s)
- Simone Belmondo
- Department of Life Sciences and Systems Biology, University of TorinoTorino, Italy
| | - Valentina Fiorilli
- Istituto per la Protezione Sostenibile delle Piante, Consiglio Nazionale delle RicercheTorino, Italy
| | - Jacob Pérez-Tienda
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Consejo Superior de Investigaciones CientificasGranada, Spain
| | - Nuria Ferrol
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Consejo Superior de Investigaciones CientificasGranada, Spain
| | - Roland Marmeisse
- Department of Life Sciences and Systems Biology, University of TorinoTorino, Italy
- Ecologie Microbienne, UMR CNRS 5557 - USC INRA 1364, Université Lyon 1, Université de LyonVilleurbanne, France
| | - Luisa Lanfranco
- Department of Life Sciences and Systems Biology, University of TorinoTorino, Italy
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Budak SO, Zhou M, Brouwer C, Wiebenga A, Benoit I, Di Falco M, Tsang A, de Vries RP. A genomic survey of proteases in Aspergilli. BMC Genomics 2014; 15:523. [PMID: 24965873 PMCID: PMC4102723 DOI: 10.1186/1471-2164-15-523] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 06/18/2014] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Proteases can hydrolyze peptides in aqueous environments. This property has made proteases the most important industrial enzymes by taking up about 60% of the total enzyme market. Microorganisms are the main sources for industrial protease production due to their high yield and a wide range of biochemical properties. Several Aspergilli have the ability to produce a variety of proteases, but no comprehensive comparative study has been carried out on protease productivity in this genus so far. RESULTS We have performed a combined analysis of comparative genomics, proteomics and enzymology tests on seven Aspergillus species grown on wheat bran and sugar beet pulp. Putative proteases were identified by homology search and Pfam domains. These genes were then clusters based on orthology and extracellular proteases were identified by protein subcellular localization prediction. Proteomics was used to identify the secreted enzymes in the cultures, while protease essays with and without inhibitors were performed to determine the overall protease activity per protease class. All this data was then integrated to compare the protease productivities in Aspergilli. CONCLUSIONS Genomes of Aspergillus species contain a similar proportion of protease encoding genes. According to comparative genomics, proteomics and enzymatic experiments serine proteases make up the largest group in the protease spectrum across the species. In general wheat bran gives higher induction of proteases than sugar beet pulp. Interesting differences of protease activity, extracellular enzyme spectrum composition, protein occurrence and abundance were identified for species. By combining in silico and wet-lab experiments, we present the intriguing variety of protease productivity in Aspergilli.
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Affiliation(s)
- Sebnem Ozturkoglu Budak
- />CBS-KNAW Fungal Biodiversity Center, Uppsalalaan 8, Utrecht, 3584 CT The Netherlands
- />Faculty of Agriculture, Department of Dairy Technology, University of Ankara, Ankara, Turkey
- />Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands
| | - Miaomiao Zhou
- />CBS-KNAW Fungal Biodiversity Center, Uppsalalaan 8, Utrecht, 3584 CT The Netherlands
- />Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands
| | - Carlo Brouwer
- />CBS-KNAW Fungal Biodiversity Center, Uppsalalaan 8, Utrecht, 3584 CT The Netherlands
| | - Ad Wiebenga
- />CBS-KNAW Fungal Biodiversity Center, Uppsalalaan 8, Utrecht, 3584 CT The Netherlands
- />Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands
| | - Isabelle Benoit
- />CBS-KNAW Fungal Biodiversity Center, Uppsalalaan 8, Utrecht, 3584 CT The Netherlands
- />Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands
| | - Marcos Di Falco
- />Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke Street West, Montreal, QC H4B 1R6 Canada
| | - Adrian Tsang
- />Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke Street West, Montreal, QC H4B 1R6 Canada
| | - Ronald P de Vries
- />CBS-KNAW Fungal Biodiversity Center, Uppsalalaan 8, Utrecht, 3584 CT The Netherlands
- />Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands
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Genetic surgery in fungi: employing site-specific recombinases for genome manipulation. Appl Microbiol Biotechnol 2014; 98:1971-82. [DOI: 10.1007/s00253-013-5480-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 12/16/2013] [Accepted: 12/17/2013] [Indexed: 12/21/2022]
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25
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Regulation of sulphur assimilation is essential for virulence and affects iron homeostasis of the human-pathogenic mould Aspergillus fumigatus. PLoS Pathog 2013; 9:e1003573. [PMID: 24009505 PMCID: PMC3757043 DOI: 10.1371/journal.ppat.1003573] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 07/08/2013] [Indexed: 11/19/2022] Open
Abstract
Sulphur is an essential element that all pathogens have to absorb from their surroundings in order to grow inside their infected host. Despite its importance, the relevance of sulphur assimilation in fungal virulence is largely unexplored. Here we report a role of the bZIP transcription factor MetR in sulphur assimilation and virulence of the human pathogen Aspergillus fumigatus. The MetR regulator is essential for growth on a variety of sulphur sources; remarkably, it is fundamental for assimilation of inorganic S-sources but dispensable for utilization of methionine. Accordingly, it strongly supports expression of genes directly related to inorganic sulphur assimilation but not of genes connected to methionine metabolism. On a broader scale, MetR orchestrates the comprehensive transcriptional adaptation to sulphur-starving conditions as demonstrated by digital gene expression analysis. Surprisingly, A. fumigatus is able to utilize volatile sulphur compounds produced by its methionine catabolism, a process that has not been described before and that is MetR-dependent. The A. fumigatus MetR transcriptional activator is important for virulence in both leukopenic mice and an alternative mini-host model of aspergillosis, as it was essential for the development of pulmonary aspergillosis and supported the systemic dissemination of the fungus. MetR action under sulphur-starving conditions is further required for proper iron regulation, which links regulation of sulphur metabolism to iron homeostasis and demonstrates an unprecedented regulatory crosstalk. Taken together, this study provides evidence that regulation of sulphur assimilation is not only crucial for A. fumigatus virulence but also affects the balance of iron in this prime opportunistic pathogen.
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26
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Roles of different peptide transporters in nutrient acquisition in Candida albicans. EUKARYOTIC CELL 2013; 12:520-8. [PMID: 23376942 DOI: 10.1128/ec.00008-13] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Fungi possess two distinct proton-coupled peptide transport systems, the dipeptide/tripeptide transporters (PTR) and the oligopeptide transporters (OPT), which enable them to utilize peptides as nutrients. In the pathogenic yeast Candida albicans, peptide transporters are encoded by gene families consisting of two PTR genes and eight OPT genes. To gain insight into the functions and importance of specific peptide transporters, we generated mutants lacking the two dipeptide/tripeptide transporters Ptr2 and Ptr22, as well as the five major oligopeptide transporters Opt1 to Opt5. These mutants were unable to grow in media containing peptides as the sole nitrogen source. Forced expression of individual peptide transporters in the septuple mutants showed that Ptr2 and Ptr22 could utilize all tested dipeptides as substrates but differed in their abilities to transport specific tripeptides. Interestingly, several oligopeptide transporters, which are thought to transport peptides consisting of more than three amino acids, also mediated the uptake of tripeptides. Opt1 especially turned out to be a highly flexible transporter that enabled growth on all tripeptides tested and could even utilize a dipeptide, a function that has never been ascribed to this family of peptide transporters. Despite their inability to grow on proteins or peptides, the opt1Δ opt2Δ opt3Δ opt4Δ opt5Δ ptr2Δ ptr22Δ septuple mutants had no in vivo fitness defect in a mouse model of gastrointestinal colonization. Therefore, the nutritional versatility of C. albicans enables it to utilize alternative nitrogen sources in this host niche, which probably contributes to its success as a commensal and pathogen in mammalian hosts.
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27
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Heinekamp T, Thywißen A, Macheleidt J, Keller S, Valiante V, Brakhage AA. Aspergillus fumigatus melanins: interference with the host endocytosis pathway and impact on virulence. Front Microbiol 2013; 3:440. [PMID: 23346079 PMCID: PMC3548413 DOI: 10.3389/fmicb.2012.00440] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 12/19/2012] [Indexed: 11/13/2022] Open
Abstract
The opportunistic human pathogenic fungus Aspergillus fumigatus produces at least two types of melanin, namely pyomelanin and dihydroxynaphthalene (DHN) melanin. Pyomelanin is produced during tyrosine catabolism via accumulation of homogentisic acid. Although pyomelanin protects the fungus against reactive oxygen species (ROS) and acts as a defense compound in response to cell wall stress, mutants deficient for pyomelanin biosynthesis do not differ in virulence when tested in a murine infection model for invasive pulmonary aspergillosis. DHN melanin is responsible for the characteristic gray-greenish color of A. fumigatus conidia. Mutants lacking a functional polyketide synthase PksP, the enzyme responsible for the initial step in DHN-melanin formation, i.e., the synthesis of naphthopyrone, produce white spores and are attenuated in virulence. The activity of PksP was found to be essential not only for inhibition of apoptosis of phagocytes by interfering with the host PI3K/Akt signaling cascade but also for effective inhibition of acidification of conidia-containing phagolysosomes. These features allow A. fumigatus to survive in phagocytes and thereby to escape from human immune effector cells and to become a successful pathogen.
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Affiliation(s)
- Thorsten Heinekamp
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute Jena, Germany
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28
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Thakur A, Bachhawat AK. Mutations in the N-terminal region of the Schizosaccharomyces pombe glutathione transporter pgt1⁺ allows functional expression in Saccharomyces cerevisiae. Yeast 2012; 30:45-54. [PMID: 23280723 DOI: 10.1002/yea.2939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 11/23/2012] [Indexed: 11/11/2022] Open
Abstract
Pgt1p encodes a glutathione transporter in Schizosaccharomyces pombe, orthologous to the Saccharomyces cerevisiae glutathione transporter, Hgt1p. Despite high similarity to Hgt1p, Pgt1p failed to display functionality during heterologous expression in S. cerevisiae. In the present study we employed a genetic strategy to investigate the reason behind the non-functionality of pgt1⁺ in S. cerevisiae. Functional mutants were isolated after in vitro mutagenesis. Several mutants were obtained and four mutants analysed. Among these, three yielded different point mutations in the N-terminal region (301-350 bp) of the transporter before the first transmembrane domain, while one mutant contained a deletion of 42 nucleotides within the same region. The mutant pgt1⁺ proteins not only expressed and localized correctly, but displayed high-affinity glutathione transport capabilities in S. cerevisae. Comparison of wild-type pgt1⁺ with the functional mutants revealed that a loss in protein expression was responsible for lack of functionality of wild-type pgt1⁺ in S. cerevisiae. The mRNA levels in wild-type and mutants were comparable, suggesting that the block was in translation. The formation of a strong stem-loop structure appeared to be responsible for inefficient translation in pgt1⁺ and disruption of these structures in the mutants was probably permitting translation. This was confirmed by making silent mutations in this region of wild-type pgt1⁺, which led to their functionality in S. cerevisiae. This genetic strategy to relieve functional blocks in expression should greatly facilitate the study of these and other transporters from more intractable genetic organisms in a heterologous expression system.
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Affiliation(s)
- Anil Thakur
- Institute of Microbial Technology-CSIR, Sector 39-A, Chandigarh 160036, India
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29
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Amich J, Krappmann S. Deciphering metabolic traits of the fungal pathogen Aspergillus fumigatus: redundancy vs. essentiality. Front Microbiol 2012; 3:414. [PMID: 23264772 PMCID: PMC3525513 DOI: 10.3389/fmicb.2012.00414] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 11/15/2012] [Indexed: 11/13/2022] Open
Abstract
Incidence rates of infections caused by environmental opportunistic fungi have risen over recent decades. Aspergillus species have emerged as serious threat for the immunecompromised, and detailed knowledge about virulence-determining traits is crucial for drug target identification. As a prime saprobe, A. fumigatus has evolved to efficiently adapt to various stresses and to sustain nutritional supply by osmotrophy, which is characterized by extracellular substrate digestion followed by efficient uptake of breakdown products that are then fed into the fungal primary metabolism. These intrinsic metabolic features are believed to be related with its virulence ability. The plethora of genes that encode underlying effectors has hampered their in-depth analysis with respect to pathogenesis. Recent developments in Aspergillus molecular biology allow conditional gene expression or comprehensive targeting of gene families to cope with redundancy. Furthermore, identification of essential genes that are intrinsically connected to virulence opens accurate perspectives for novel targets in antifungal therapy.
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Affiliation(s)
- Jorge Amich
- Research Center for Infectious Diseases, Julius-Maximilians-Universität Würzburg Würzburg, Germany
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30
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Menon V, Rao M. A low-molecular-mass aspartic protease inhibitor from a novel Penicillium sp.: implications in combating fungal infections. Microbiology (Reading) 2012; 158:1897-1907. [DOI: 10.1099/mic.0.058511-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Vishnu Menon
- Division of Biochemical Sciences, National Chemical Laboratory, Pune 411 008, India
| | - Mala Rao
- Division of Biochemical Sciences, National Chemical Laboratory, Pune 411 008, India
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