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Kumari D, Sachivkina N, Pasrija R. Investigation of the influence of pH and temperature on melanization and survival under oxidative stress in Cryptococcus neoformans. Arch Microbiol 2024; 206:355. [PMID: 39017938 DOI: 10.1007/s00203-024-04080-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 07/04/2024] [Accepted: 07/08/2024] [Indexed: 07/18/2024]
Abstract
Cryptococcus neoformans is an opportunistic pathogenic fungus that produces melanin during infection, an important virulence factor in Cryptococcal infections that enhances the ability of the fungus to resist immune defense. This fungus can synthesize melanin from a variety of substrates, including L-DOPA (L-3,4-dihydroxyphenylalanine). Since melanin protects the fungus from various stress factors such as oxidative, nitrosative, extreme heat and cold stress; we investigated the effects of environmental conditions on melanin production and survival. In this study, we investigated the effects of different pH values (5.6, 7.0 and 8.5) and temperatures (30 °C and 37 °C) on melanization and cell survival using a microtiter plate-based melanin production assay and an oxidative stress assay, respectively. In addition, the efficacy of compounds known to inhibit laccase involved in melanin synthesis, i.e., tunicamycin, β-mercaptoethanol, dithiothreitol, sodium azide and caspofungin on melanization was evaluated and their sensitivity to temperature and pH changes was measured. The results showed that melanin content correlated with pH and temperature changes and that pH 8.5 and 30 °C, were best for melanin production. Besides that, melanin production protects the fungal cells from oxidative stress induced by hydrogen peroxide. Thus, changes in pH and temperature drastically alter melanin production in C. neoformans and it correlates with the fungal survival. Due to the limited antifungal repertoire and the development of resistance in cryptococcal infections, the investigation of environmental conditions in the regulation of melanization and survival of C. neoformans could be useful for future research and clinical phasing.
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Affiliation(s)
- Deepika Kumari
- Department of Biochemistry, Maharshi Dayanand University, Rohtak, 124001, India
| | - Nadezhda Sachivkina
- Department of Microbiology, Peoples' Friendship University of Russia, Moscow, 117198, Russia
| | - Ritu Pasrija
- Department of Biochemistry, Maharshi Dayanand University, Rohtak, 124001, India.
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Pianalto KM, Telzrow CL, Harding HB, Brooks JT, Granek JA, Gushiken-Ibañez E, LeibundGut-Landmann S, Heitman J, Ianiri G, Alspaugh JA. Malassezia responds to environmental pH signals through the conserved Rim/Pal pathway. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.11.603086. [PMID: 39026808 PMCID: PMC11257548 DOI: 10.1101/2024.07.11.603086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
During mammalian colonization and infection, microorganisms must be able to rapidly sense and adapt to changing environmental conditions including alterations in extracellular pH. The fungus-specific Rim/Pal signaling pathway is one process that supports microbial adaptation to alkaline pH. This cascading series of interacting proteins terminates in the proteolytic activation of the highly conserved Rim101/PacC protein, a transcription factor that mediates microbial responses that favor survival in neutral/alkaline pH growth conditions, including many mammalian tissues. We identified the putative Rim pathway proteins Rim101 and Rra1 in the human skin colonizing fungus Malassezia sympodialis. Gene deletion by transconjugation and homologous recombination revealed that Rim101 and Rra1 are required for M. sympodialis growth at higher pH. Additionally, comparative transcriptional analysis of the mutant strains compared to wild-type suggested mechanisms for fungal adaptation to alkaline conditions. These pH-sensing signaling proteins are required for optimal growth in a murine model of atopic dermatitis, a pathological condition associated with increased skin pH. Together these data elucidate both conserved and phylum-specific features of microbial adaptation to extracellular stresses.
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Affiliation(s)
- Kaila M. Pianalto
- Departments of Medicine, Duke University School of Medicine, Durham, NC, USA
- Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA
| | - Calla L. Telzrow
- Departments of Medicine, Duke University School of Medicine, Durham, NC, USA
- Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA
| | - Hannah Brown Harding
- Departments of Medicine, Duke University School of Medicine, Durham, NC, USA
- Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA
| | - Jacob T. Brooks
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC, USA
| | - Joshua A. Granek
- Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA
- Biostatistics and Bioinformatics, Duke University School of Medicine, Durham, NC, USA
| | - Eduardo Gushiken-Ibañez
- Section of Immunology at Vetsuisse Faculty, University of Zurich, Switzerland
- Institute of Experimental Immunology, University of Zurich, Switzerland
| | - Salomé LeibundGut-Landmann
- Section of Immunology at Vetsuisse Faculty, University of Zurich, Switzerland
- Institute of Experimental Immunology, University of Zurich, Switzerland
| | - Joseph Heitman
- Departments of Medicine, Duke University School of Medicine, Durham, NC, USA
- Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA
- Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA
- Cell Biology, Duke University School of Medicine, Durham, NC, USA
| | - Giuseppe Ianiri
- Department of Agricultural, Environmental and Food Sciences, Università degli Studi del Molise, Italy
| | - J. Andrew Alspaugh
- Departments of Medicine, Duke University School of Medicine, Durham, NC, USA
- Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA
- Cell Biology, Duke University School of Medicine, Durham, NC, USA
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Picazo I, Espeso EA. Interconnections between the Cation/Alkaline pH-Responsive Slt and the Ambient pH Response of PacC/Pal Pathways in Aspergillus nidulans. Cells 2024; 13:651. [PMID: 38607089 PMCID: PMC11011638 DOI: 10.3390/cells13070651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 03/21/2024] [Accepted: 04/05/2024] [Indexed: 04/13/2024] Open
Abstract
In the filamentous ascomycete Aspergillus nidulans, at least three high hierarchy transcription factors are required for growth at extracellular alkaline pH: SltA, PacC and CrzA. Transcriptomic profiles depending on alkaline pH and SltA function showed that pacC expression might be under SltA regulation. Additional transcriptional studies of PacC and the only pH-regulated pal gene, palF, confirmed both the strong dependence on ambient pH and the function of SltA. The regulation of pacC expression is dependent on the activity of the zinc binuclear (C6) cluster transcription factor PacX. However, we found that the ablation of sltA in the pacX- mutant background specifically prevents the increase in pacC expression levels without affecting PacC protein levels, showing a novel specific function of the PacX factor. The loss of sltA function causes the anomalous proteolytic processing of PacC and a reduction in the post-translational modifications of PalF. At alkaline pH, in a null sltA background, PacC72kDa accumulates, detection of the intermediate PacC53kDa form is extremely low and the final processed form of 27 kDa shows altered electrophoretic mobility. Constitutive ubiquitination of PalF or the presence of alkalinity-mimicking mutations in pacC, such as pacCc14 and pacCc700, resembling PacC53kDa and PacC27kDa, respectively, allowed the normal processing of PacC but did not rescue the alkaline pH-sensitive phenotype caused by the null sltA allele. Overall, data show that Slt and PacC/Pal pathways are interconnected, but the transcription factor SltA is on a higher hierarchical level than PacC on regulating the tolerance to the ambient alkalinity in A. nidulans.
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Affiliation(s)
| | - Eduardo A. Espeso
- Department of Molecular and Cellular Biology, Centro de Investigaciones Biológicas (CIB) Margarita Salas, Spanish Research Council (CSIC), Ramiro de Maeztu, 9, 28040 Madrid, Spain;
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Albacar M, Casamayor A, Ariño J. Harnessing alkaline-pH regulatable promoters for efficient methanol-free expression of enzymes of industrial interest in Komagataella Phaffii. Microb Cell Fact 2024; 23:99. [PMID: 38566096 PMCID: PMC10985989 DOI: 10.1186/s12934-024-02362-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Accepted: 03/11/2024] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND The yeast Komagataella phaffii has become a very popular host for heterologous protein expression, very often based on the use of the AOX1 promoter, which becomes activated when cells are grown with methanol as a carbon source. However, the use of methanol in industrial settings is not devoid of problems, and therefore, the search for alternative expression methods has become a priority in the last few years. RESULTS We recently reported that moderate alkalinization of the medium triggers a fast and wide transcriptional response in K. phaffii. Here, we present the utilization of three alkaline pH-responsive promoters (pTSA1, pHSP12 and pPHO89) to drive the expression of a secreted phytase enzyme by simply shifting the pH of the medium to 8.0. These promoters offer a wide range of strengths, and the production of phytase could be modulated by adjusting the pH to specific values. The TSA1 and PHO89 promoters offered exquisite regulation, with virtually no enzyme production at acidic pH, while limitation of Pi in the medium further potentiated alkaline pH-driven phytase expression from the PHO89 promoter. An evolved strain based on this promoter was able to produce twice as much phytase as the reference pAOX1-based strain. Functional mapping of the TSA1 and HSP12 promoters suggests that both contain at least two alkaline pH-sensitive regulatory regions. CONCLUSIONS Our work shows that the use of alkaline pH-regulatable promoters could be a useful alternative to methanol-based expression systems, offering advantages in terms of simplicity, safety and economy.
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Affiliation(s)
- Marcel Albacar
- Institut de Biotecnologia i Biomedicina & Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Spain
| | - Antonio Casamayor
- Institut de Biotecnologia i Biomedicina & Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Spain
| | - Joaquín Ariño
- Institut de Biotecnologia i Biomedicina & Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Spain.
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Hefny ZA, Ji B, Elsemman IE, Nielsen J, Van Dijck P. Transcriptomic meta-analysis to identify potential antifungal targets in Candida albicans. BMC Microbiol 2024; 24:66. [PMID: 38413885 PMCID: PMC10898158 DOI: 10.1186/s12866-024-03213-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 02/06/2024] [Indexed: 02/29/2024] Open
Abstract
BACKGROUND Candida albicans is a fungal pathogen causing human infections. Here we investigated differential gene expression patterns and functional enrichment in C. albicans strains grown under different conditions. METHODS A systematic GEO database search identified 239 "Candida albicans" datasets, of which 14 were selected after rigorous criteria application. Retrieval of raw sequencing data from the ENA database was accompanied by essential metadata extraction from dataset descriptions and original articles. Pre-processing via the tailored nf-core pipeline for C. albicans involved alignment, gene/transcript quantification, and diverse quality control measures. Quality assessment via PCA and DESeq2 identified significant genes (FDR < = 0.05, log2-fold change > = 1 or <= -1), while topGO conducted GO term enrichment analysis. Exclusions were made based on data quality and strain relevance, resulting in the selection of seven datasets from the SC5314 strain background for in-depth investigation. RESULTS The meta-analysis of seven selected studies unveiled a substantial number of genes exhibiting significant up-regulation (24,689) and down-regulation (18,074). These differentially expressed genes were further categorized into 2,497 significantly up-regulated and 2,573 significantly down-regulated Gene Ontology (GO) IDs. GO term enrichment analysis clustered these terms into distinct groups, providing insights into the functional implications. Three target gene lists were compiled based on previous studies, focusing on central metabolism, ion homeostasis, and pathogenicity. Frequency analysis revealed genes with higher occurrence within the identified GO clusters, suggesting their potential as antifungal targets. Notably, the genes TPS2, TPS1, RIM21, PRA1, SAP4, and SAP6 exhibited higher frequencies within the clusters. Through frequency analysis within the GO clusters, several key genes emerged as potential targets for antifungal therapies. These include RSP5, GLC7, SOD2, SOD5, SOD1, SOD6, SOD4, SOD3, and RIM101 which exhibited higher occurrence within the identified clusters. CONCLUSION This comprehensive study significantly advances our understanding of the dynamic nature of gene expression in C. albicans. The identification of genes with enhanced potential as antifungal drug targets underpins their value for future interventions. The highlighted genes, including TPS2, TPS1, RIM21, PRA1, SAP4, SAP6, RSP5, GLC7, SOD2, SOD5, SOD1, SOD6, SOD4, SOD3, and RIM101, hold promise for the development of targeted antifungal therapies.
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Affiliation(s)
- Zeinab Abdelmoghis Hefny
- Laboratory of Molecular Cell Biology, Department of Biology, Katholieke Universiteit Leuven, Kasteelpark Arenberg 31, Leuven, B-3001, Belgium
| | - Boyang Ji
- BioInnovation Institute, Ole Maaløes Vej 3, Copenhagen, DK2200, Denmark
| | - Ibrahim E Elsemman
- Department of Information Systems, Faculty of Computers and Information, Assiut University, Assiut, 2071515, Egypt
| | - Jens Nielsen
- BioInnovation Institute, Ole Maaløes Vej 3, Copenhagen, DK2200, Denmark.
- Department of Life Sciences, Chalmers University of Technology, Kemivägen 10, SE41296, Gothenburg, SE41296, Sweden.
| | - Patrick Van Dijck
- Laboratory of Molecular Cell Biology, Department of Biology, Katholieke Universiteit Leuven, Kasteelpark Arenberg 31, Leuven, B-3001, Belgium.
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Chen SY, Chang CK, Lan CY. Antimicrobial peptide LL-37 disrupts plasma membrane and calcium homeostasis in Candida albicans via the Rim101 pathway. Microbiol Spectr 2023; 11:e0255123. [PMID: 37888991 PMCID: PMC10715129 DOI: 10.1128/spectrum.02551-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 09/19/2023] [Indexed: 10/28/2023] Open
Abstract
IMPORTANCE Candida albicans is a major human fungal pathogen, and antimicrobial peptides are key components of innate immunity. Studying the interplay between C. albicans and human antimicrobial peptides would enhance a better understanding of pathogen-host interactions. Moreover, potential applications of antimicrobial peptides in antifungal therapy have aroused great interest. This work explores new mechanisms of LL-37 against C. albicans and reveals the complex connection among calcium homeostasis, oxidative stress, signaling, and possibly organelle interaction. Notably, these findings support the possible use of antimicrobial peptides to prevent and treat fungal infections.
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Affiliation(s)
- Sheng-Yuan Chen
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Che-Kang Chang
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Chung-Yu Lan
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan
- Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan
- School of Medicine, National Tsing Hua University, Hsinchu, Taiwan
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7
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Guan G, Li S, Bing J, Liu L, Tao L. The Rfg1 and Bcr1 transcription factors regulate acidic pH-induced filamentous growth in Candida albicans. Microbiol Spectr 2023; 11:e0178923. [PMID: 37933972 PMCID: PMC10715123 DOI: 10.1128/spectrum.01789-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 09/23/2023] [Indexed: 11/08/2023] Open
Abstract
IMPORTANCE Candida albicans is a human commensal and frequent pathogen that encounters a wide range of pH stresses. The ability of C. albicans to adapt to changes in extracellular pH is crucial for its success in colonization and pathogenesis. The Rim101 pH sensing pathway is well known to govern neutral-alkaline pH responses in this pathogen. Here, we report a novel Rfg1-Bcr1 regulatory pathway that governs acidic pH responses and regulates filamentous growth in C. albicans. In addition, the Rim101-Phr1 pathway, cAMP signaling pathway, transcription factors Efg1 and Flo8, and hyphal-specific G1 cyclin Hgc1 cooperate with this regulation. Our findings provide new insights into the regulatory mechanism of acidic pH response in C. albicans.
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Affiliation(s)
- Guobo Guan
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Shuaihu Li
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Jian Bing
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Ling Liu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Li Tao
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
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Gorczyca M, Nicaud JM, Celińska E. Transcription factors enhancing synthesis of recombinant proteins and resistance to stress in Yarrowia lipolytica. Appl Microbiol Biotechnol 2023:10.1007/s00253-023-12607-z. [PMID: 37318637 DOI: 10.1007/s00253-023-12607-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/11/2023] [Accepted: 05/17/2023] [Indexed: 06/16/2023]
Abstract
Resistance to environmental stress and synthesis of recombinant proteins (r-Prots) are both complex, strongly interconnected biological traits relying on orchestrated contribution of multiple genes. This, in turn, makes their engineering a challenging task. One of the possible strategies is to modify the operation of transcription factors (TFs) associated with these complex traits. The aim of this study was to examine the potential implications of selected five TFs (HSF1-YALI0E13948g, GZF1-YALI0D20482g, CRF1-YALI0B08206g, SKN7-YALI0D14520g, and YAP-like-YALI0D07744g) in stress resistance and/or r-Prot synthesis in Yarrowia lipolytica. The selected TFs were over-expressed or deleted (OE/KO) in a host strain synthesizing a reporter r-Prot. The strains were subjected to phenotype screening under different environmental conditions (pH, oxygen availability, temperature, and osmolality), and the obtained data processing was assisted by mathematical modeling. The results demonstrated that growth and the r-Prot yields under specific conditions can be significantly increased or decreased due to the TFs' engineering. Environmental factors "awakening" individual TFs were indicated, and their contribution was mathematically described. For example, OE of Yap-like TF was proven to alleviate growth retardation under high pH, while Gzf1 and Hsf1 were shown to serve as universal enhancers of r-Prot production in Y. lipolytica. On the other hand, KO of SKN7 and HSF1 disabled growth under hyperosmotic stress. This research demonstrates the usefulness of the TFs engineering approach in the manipulation of complex traits and evidences newly identified functions of the studied TFs. KEY POINTS: • Function and implication in complex traits of 5 TFs in Y. lipolytica were studied. • Gzf1 and Hsf1 are the universal r-Prots synthesis enhancers in Y. lipolytica. • Yap-like TF's activity is pH-dependent; Skn7 and Hsf1 act in osmostress response.
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Affiliation(s)
- Maria Gorczyca
- Department of Biotechnology and Food Microbiology, Poznan University of Life Sciences, 60-637, Poznań, Poland
| | - Jean-Marc Nicaud
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
| | - Ewelina Celińska
- Department of Biotechnology and Food Microbiology, Poznan University of Life Sciences, 60-637, Poznań, Poland.
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Albacar M, Zekhnini A, Pérez-Valle J, Martínez JL, Casamayor A, Ariño J. Transcriptomic profiling of the yeast Komagataella phaffii in response to environmental alkalinization. Microb Cell Fact 2023; 22:63. [PMID: 37013612 PMCID: PMC10071690 DOI: 10.1186/s12934-023-02074-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 03/27/2023] [Indexed: 04/05/2023] Open
Abstract
BACKGROUND Adaptation to alkalinization of the medium in fungi involves an extensive remodeling of gene expression. Komagataella phaffii is an ascomycetous yeast that has become an organism widely used for heterologous protein expression. We explore here the transcriptional impact of moderate alkalinization in this yeast, in search of suitable novel promoters able to drive transcription in response to the pH signal. RESULTS In spite of a minor effect on growth, shifting the cultures from pH 5.5 to 8.0 or 8.2 provokes significant changes in the mRNA levels of over 700 genes. Functional categories such as arginine and methionine biosynthesis, non-reductive iron uptake and phosphate metabolism are enriched in induced genes, whereas many genes encoding iron-sulfur proteins or members of the respirasome were repressed. We also show that alkalinization is accompanied by oxidative stress and we propose this circumstance as a common trigger of a subset of the observed changes. PHO89, encoding a Na+/Pi cotransporter, appears among the most potently induced genes by high pH. We demonstrate that this response is mainly based on two calcineurin-dependent response elements located in its promoter, thus indicating that alkalinization triggers a calcium-mediated signal in K. phaffii. CONCLUSIONS This work defines in K. phaffii a subset of genes and diverse cellular pathways that are altered in response to moderate alkalinization of the medium, thus setting the basis for developing novel pH-controlled systems for heterologous protein expression in this fungus.
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Affiliation(s)
- Marcel Albacar
- Institut de Biotecnologia i Biomedicina & Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Spain
| | - Abdelghani Zekhnini
- Institut de Biotecnologia i Biomedicina & Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Spain
| | - Jorge Pérez-Valle
- Institut de Biotecnologia i Biomedicina & Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Spain
| | - José L Martínez
- Department of Biotechnology and Biomedicine, Section for Synthetic Biology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Antonio Casamayor
- Institut de Biotecnologia i Biomedicina & Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Spain
| | - Joaquín Ariño
- Institut de Biotecnologia i Biomedicina & Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Spain.
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Khari A, Biswas B, Gangwar G, Thakur A, Puria R. Candida auris biofilm: a review on model to mechanism conservation. Expert Rev Anti Infect Ther 2023; 21:295-308. [PMID: 36755419 DOI: 10.1080/14787210.2023.2179036] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
INTRODUCTION Candida auris is included in the fungal infection category 'critical' by WHO because of associated high drug tolerance and spread at an alarming rate which if remains untouched may result in serious outbreaks. Since its discovery in 2009, several assiduous efforts by mycologists across the world have deciphered its biology including growth physiology, drug tolerance, biofilm formation, etc. The differential response of various strains from different clades poses a hurdle in drawing a final conclusion. AREAS COVERED This review provides brief insights into the understanding of C. auris biofilm. It includes information on various models developed to understand the biofilms and conservation of different signaling pathways. Significant development has been made in the recent past with the generation of relevant in vivo and ex vivo models. The role of signaling pathways in the development of biofilm is largely unknown. EXPERT OPINION The selection of an appropriate model system is a must for the accuracy and reproducibility of results. The conservation of major signaling pathways in C. auris with respect to C. albicans and S. cerevisiae highlights that initial inputs acquired from orthologs will be valuable in getting insights into the mechanism of biofilm formation and associated pathogenesis.
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Affiliation(s)
- Arsha Khari
- School of Biotechnology, Gautam Buddha University, Greater Noida, India
| | | | | | - Anil Thakur
- Regional Centre for Biotechnology, Faridabad, India
| | - Rekha Puria
- School of Biotechnology, Gautam Buddha University, Greater Noida, India
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Andersson M(A, Vornanen-Winqvist C, Koivisto T, Varga A, Mikkola R, Kredics L, Salonen H. Composition of Culturable Microorganisms in Dusts Collected from Sport Facilities in Finland during the COVID-19 Pandemic. Pathogens 2023; 12:pathogens12020339. [PMID: 36839611 PMCID: PMC9963892 DOI: 10.3390/pathogens12020339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 02/03/2023] [Accepted: 02/15/2023] [Indexed: 02/19/2023] Open
Abstract
Sport facilities represent extreme indoor environments due to intense cleaning and disinfection. The aim of this study was to describe the composition of the cultivated microbiota in dust samples collected in sport facilities during the COVID-19 pandemic. A dust sample is defined as the airborne dust sedimented on 0.02 m2 within 28 d. The results show that the microbial viable counts in samples of airborne dust (n = 9) collected from seven Finnish sport facilities during the pandemic contained a high proportion of pathogenic filamentous fungi and a low proportion of bacteria. The microbial viable counts were between 14 CFU and 189 CFU per dust sample. In seven samples from sport facilities, 20-85% of the microbial viable counts were fungi. Out of 123 fungal colonies, 47 colonies belonged to the potentially pathogenic sections of Aspergillus (Sections Fumigati, Nigri, and Flavi). Representatives of each section were identified as Aspergillus fumigatus, A. flavus, A. niger and A. tubingensis. Six colonies belonged to the genus Paecilomyces. In six samples of dust, a high proportion (50-100%) of the total fungal viable counts consisted of these potentially pathogenic fungi. A total of 70 isolates were considered less likely to be pathogenic, and were identified as Aspergillus section Nidulantes, Chaetomium cochliodes and Penicillium sp. In the rural (n = 2) and urban (n = 7) control dust samples, the microbial viable counts were >2000 CFU and between 44 CFU and 215 CFU, respectively, and consisted mainly of bacteria. The low proportion of bacteria and the high proportion of stress tolerant, potentially pathogenic fungi in the dust samples from sport facilities may reflect the influence of disinfection on microbial communities.
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Affiliation(s)
- Maria (Aino) Andersson
- Department of Civil Engineering, School of Engineering, Aalto University, P.O. Box 12100, FI-00076 Aalto, Finland
- Correspondence: ; Tel.: +358-405-508-934
| | - Camilla Vornanen-Winqvist
- Department of Civil Engineering, School of Engineering, Aalto University, P.O. Box 12100, FI-00076 Aalto, Finland
| | - Tuomas Koivisto
- Department of Civil Engineering, School of Engineering, Aalto University, P.O. Box 12100, FI-00076 Aalto, Finland
| | - András Varga
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Közép Fasor 52, H-6726 Szeged, Hungary
| | - Raimo Mikkola
- Department of Civil Engineering, School of Engineering, Aalto University, P.O. Box 12100, FI-00076 Aalto, Finland
| | - László Kredics
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Közép Fasor 52, H-6726 Szeged, Hungary
| | - Heidi Salonen
- Department of Civil Engineering, School of Engineering, Aalto University, P.O. Box 12100, FI-00076 Aalto, Finland
- International Laboratory for Air Quality and Health, Faculty of Science, School of Earth & Atmospheric Sciences, Queensland University of Technology, 2 George Street, Brisbane, QLD 4000, Australia
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12
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Moghimi S, Shafiei M, Foroumadi A. Drug design strategies for the treatment azole-resistant candidiasis. Expert Opin Drug Discov 2022; 17:879-895. [PMID: 35793245 DOI: 10.1080/17460441.2022.2098949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Despite the availability of novel antifungals and therapeutic strategies, the rate of global mortality linked to invasive fungal diseases from fungal infection remains high. Candida albicans account for the most invasive mycosis produced by yeast. Thus, the current arsenal of medicinal chemists is focused on finding new effective agents with lower toxicity and broad-spectrum activity. In this review article, recent efforts to find effective agents against azole-resistant candidiasis, a common fungal infection, are covered. AREAS COVERED Herein, the authors outlined all azole-based compounds, dual target, and new scaffolds (non-azole-based compounds) which were effective against azole-resistant candidiasis. In addition, the mechanism of action and SAR studies were also discussed, if the data were available. EXPERT OPINION The current status of fungal infections and the drawbacks of existing drugs have encouraged scientists to find novel scaffolds based on different methods like virtual screening and fragment-based drug discovery. Machine learning and in-silico methods have found their role in this field and experts are hopeful to find novel scaffolds/compounds by using these methods.
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Affiliation(s)
- Setareh Moghimi
- Drug Design and Development Research Center, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Shafiei
- Drug Design and Development Research Center, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran.,Department of Medicinal Chemistry, Faculty of Pharmacy, Birjand University of Medical Sciences, Birjand, Iran
| | - Alireza Foroumadi
- Drug Design and Development Research Center, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran.,Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
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13
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Jampilek J. Novel avenues for identification of new antifungal drugs and current challenges. Expert Opin Drug Discov 2022; 17:949-968. [PMID: 35787715 DOI: 10.1080/17460441.2022.2097659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION : Some of otherwise useful fungi are pathogenic to humans, and unfortunately, the number of these pathogens is increasing. In addition to common skin infections, these opportunistic pathogens are able to cause severe, often incurable, systemic mycoses. AREAS COVERED : The number of antifungal drugs is limited, especially drugs that can be used for systemic administration, and resistance to these drugs is very common. This review summarizes various approaches to the discovery and development of new antifungal drugs, provides an overview of the most important molecules in terms of basic (laboratory) research and compounds currently in clinical trials, and focuses on drug repurposing strategy, while providing an overview of drugs of other indications that have been tested in vitro for their antifungal activity for possible expansion of antifungal drugs and/or support of existing antimycotics. EXPERT OPINION : Despite the limitations of the research of new antifungal drugs by pharmaceutical manufacturers, in addition to innovated molecules based on clinically used drugs, several completely new small entities with unique mechanisms of actions have been identified. The identification of new molecular targets that offer alternatives for the development of new unique selective antifungal highly effective agents has been an important outcome of repurposing of non-antifungal drugs to antifungal drug. Also, given the advances in monoclonal antibodies and their application to immunosuppressed patients, it may seem possible to predict a more optimistic future for antifungal therapy than has been the case in recent decades.
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Affiliation(s)
- Josef Jampilek
- Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 842 15 Bratislava, Slovakia.,Institute of Neuroimmunology, Slovak Academy of Sciences, Dubravska Cesta 9, 845 10 Bratislava, Slovakia
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14
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Yuan XY, Li JY, Zhi QQ, Chi SD, Qu S, Luo YF, He ZM. SfgA Renders Aspergillus flavus More Stable to the External Environment. J Fungi (Basel) 2022; 8:jof8060638. [PMID: 35736121 PMCID: PMC9224668 DOI: 10.3390/jof8060638] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 06/07/2022] [Accepted: 06/08/2022] [Indexed: 02/04/2023] Open
Abstract
sfgA is known as a key negative transcriptional regulator gene of asexual sporulation and sterigmatocystin production in Aspergillus nidulans. However, here, we found that the homolog sfgA gene shows a broad and complex regulatory role in governing growth, conidiation, sclerotia formation, secondary metabolism, and environmental stress responses in Aspergillus flavus. When sfgA was deleted in A. flavus, the fungal growth was slowed, but the conidiation was significantly increased, and the sclerotia formation displayed different behavior at different temperatures, which increased at 30 °C but decreased at 36 °C. In addition, sfgA regulated aflatoxin biosynthesis in a complex way that was associated with the changes in cultured conditions, and the increased production of aflatoxin in the ∆sfgA mutant was associated with a decrease in sclerotia size. Furthermore, the ∆sfgA mutant exhibited sensitivity to osmotic, oxidative, and cell wall stresses but still produced dense conidia. Transcriptome data indicated that numerous development- and secondary-metabolism-related genes were expressed differently when sfgA was deleted. Additionally, we also found that sfgA functions downstream of fluG in A. flavus, which is consistent with the genetic position in FluG-mediated conidiation in A. nidulans. Collectively, sfgA plays a critical role in the development, secondary metabolism, and stress responses of A. flavus, and sfgA renders A. flavus more stable to the external environment.
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Affiliation(s)
- Xiao-Yu Yuan
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Science, Sun Yat-sen University, Guangzhou 510275, China; (X.-Y.Y.); (J.-Y.L.); (Q.-Q.Z.); (S.-D.C.); (S.Q.)
| | - Jie-Ying Li
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Science, Sun Yat-sen University, Guangzhou 510275, China; (X.-Y.Y.); (J.-Y.L.); (Q.-Q.Z.); (S.-D.C.); (S.Q.)
| | - Qing-Qing Zhi
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Science, Sun Yat-sen University, Guangzhou 510275, China; (X.-Y.Y.); (J.-Y.L.); (Q.-Q.Z.); (S.-D.C.); (S.Q.)
- College of Agriculture and Biology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Sheng-Da Chi
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Science, Sun Yat-sen University, Guangzhou 510275, China; (X.-Y.Y.); (J.-Y.L.); (Q.-Q.Z.); (S.-D.C.); (S.Q.)
| | - Su Qu
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Science, Sun Yat-sen University, Guangzhou 510275, China; (X.-Y.Y.); (J.-Y.L.); (Q.-Q.Z.); (S.-D.C.); (S.Q.)
| | - Yan-Feng Luo
- Guangdong Jinyinshan Environmental Protection Technology Co., Ltd., Guangzhou 510705, China;
| | - Zhu-Mei He
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Science, Sun Yat-sen University, Guangzhou 510275, China; (X.-Y.Y.); (J.-Y.L.); (Q.-Q.Z.); (S.-D.C.); (S.Q.)
- Correspondence:
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15
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State-of-the-Art Dermatophyte Infections: Epidemiology Aspects, Pathophysiology, and Resistance Mechanisms. J Fungi (Basel) 2021; 7:jof7080629. [PMID: 34436168 PMCID: PMC8401872 DOI: 10.3390/jof7080629] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 07/29/2021] [Accepted: 07/30/2021] [Indexed: 12/23/2022] Open
Abstract
The burden of fungal infections is not widely appreciated. Although these infections are responsible for over one million deaths annually, it is estimated that one billion people are affected by severe fungal diseases. Mycoses of nails and skin, primarily caused by fungi known as dermatophytes, are the most common fungal infections. Trichophyton rubrum appears to be the most common causative agent of dermatophytosis, followed by Trichophyton interdigitale. An estimated 25% of the world’s population suffers from dermatomycosis. Although these infections are not lethal, they compromise the quality of life of infected patients. The outcome of antidermatophytic treatments is impaired by various conditions, such as resistance and tolerance of certain dermatophyte strains. The adage “know your enemy” must be the focus of fungal research. There is an urgent need to increase awareness about the significance of these infections with precise epidemiological data and to improve knowledge regarding fungal biology and pathogenesis, with an emphasis on adaptive mechanisms to tackle adverse conditions from host counteractions. This review outlines the current knowledge about dermatophyte infections, with a focus on signaling pathways required for fungal infection establishment and a broad perspective on cellular and molecular factors involved in antifungal resistance and tolerance.
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16
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Farh MEA, Abdellaoui N, Seo JA. pH Changes Have a Profound Effect on Gene Expression, Hydrolytic Enzyme Production, and Dimorphism in Saccharomycopsis fibuligera. Front Microbiol 2021; 12:672661. [PMID: 34248880 PMCID: PMC8265565 DOI: 10.3389/fmicb.2021.672661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 05/25/2021] [Indexed: 11/21/2022] Open
Abstract
Saccharomycopsis fibuligera is an amylolytic yeast that plays an important role within nuruk (a traditional Korean fermentation starter) used for the production of makgeolli (Korean rice wine), which is characterized by high acidity. However, the effect of pH change (neutral to acidic) on the yeast cell to hyphal transition and carbohydrate-hydrolyzing enzyme activities for S. fibuligera has not been investigated yet. In this study, S. fibuligera strains were cultured under the different pH conditions, and the effect on the enzyme production and gene expression were investigated. An acidic pH induced a hyphal transition from yeast cell of S. fibuligera KPH12 and the hybrid strain KJJ81. In addition, both strains showed a gradual decrease in the ability to degrade starch and cellulose as the pH went down. Furthermore, a transcriptome analysis demonstrated that the pH decline caused global expression changes in genes, which were classified into five clusters. Among the differentially expressed genes (DEGs) under acidic pH, the downregulated genes were involved in protein synthesis, carbon metabolism, and RIM101 and cAMP-PKA signaling transduction pathways for the yeast-hyphal transition. A decrease in pH induced a dimorphic lifestyle switch from yeast cell formation to hyphal growth in S. fibuligera and caused a decrease in carbohydrate hydrolyzing enzyme production, as well as marked changes in the expression of genes related to enzyme production and pH adaptation. This study will help to elucidate the mechanism of adaptation of S. fibuligera to acidification that occur during the fermentation process of makgeolli using nuruk.
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Affiliation(s)
| | - Najib Abdellaoui
- School of Systems Biomedical Science, Soongsil University, Seoul, South Korea
| | - Jeong-Ah Seo
- School of Systems Biomedical Science, Soongsil University, Seoul, South Korea
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17
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The pH-Responsive Transcription Factors YlRim101 and Mhy1 Regulate Alkaline pH-Induced Filamentation in the Dimorphic Yeast Yarrowia lipolytica. mSphere 2021; 6:6/3/e00179-21. [PMID: 34011684 PMCID: PMC8265631 DOI: 10.1128/msphere.00179-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Environmental pH influences cell growth and differentiation. In the dimorphic yeast Yarrowia lipolytica, neutral-alkaline pH strongly induces the yeast-to-filament transition. However, the regulatory mechanism that governs alkaline pH-induced filamentation has been unclear. Here, we show that the pH-responsive transcription factor Y. lipolytica Rim101 (YlRim101) is a major regulator of alkaline-induced filamentation, since the deletion of YlRIM101 severely impaired filamentation at alkaline pH, whereas the constitutively active YlRIM1011-330 mutant mildly induced filamentation at acidic pH. YlRim101 controls the expression of the majority of alkaline-regulated cell wall protein genes. One of these, the cell surface glycosidase gene YlPHR1, plays a critical role in growth, cell wall function, and filamentation at alkaline pH. This finding suggests that YlRim101 promotes filamentation at alkaline pH via controlling the expression of these genes. We also show that, in addition to YlRim101, the Msn2/Msn4-like transcription factor Mhy1 is highly upregulated at alkaline pH and is essential for filamentation. However, unlike YlRim101, which specifically regulates alkaline-induced filamentation, Mhy1 regulates both alkaline- and glucose-induced filamentation, since the deletion of MHY1 abolished them both, whereas the overexpression of MHY1 induced strong filamentation irrespective of the pH or the presence of glucose. Finally, we show that YlRim101 and Mhy1 positively coregulate seven cell wall protein genes at alkaline pH, including YlPHR1 and five cell surface adhesin-like genes, three of which appear to promote filamentation. Together, these results reveal a conserved role of YlRim101 and a novel role of Mhy1 in the regulation of alkaline-induced filamentation in Y. lipolytica IMPORTANCE The regulatory mechanism that governs pH-regulated filamentation is not clear in dimorphic fungi except in Candida albicans Here, we investigated the regulation of alkaline pH-induced filamentation in Yarrowia lipolytica, a dimorphic yeast distantly related to C. albicans Our results show that the transcription factor YlRim101 and the Msn2/Msn4-like transcription factor Mhy1 are the major regulators that promote filamentation at alkaline pH. They control the expression of a number of cell wall protein genes important for cell wall organization and filamentation. Our results suggest that the Rim101/PacC homologs play a conserved role in pH-regulated filamentation in dimorphic fungi.
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18
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Lee Y, Puumala E, Robbins N, Cowen LE. Antifungal Drug Resistance: Molecular Mechanisms in Candida albicans and Beyond. Chem Rev 2021; 121:3390-3411. [PMID: 32441527 PMCID: PMC8519031 DOI: 10.1021/acs.chemrev.0c00199] [Citation(s) in RCA: 332] [Impact Index Per Article: 110.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Fungal infections are a major contributor to infectious disease-related deaths across the globe. Candida species are among the most common causes of invasive mycotic disease, with Candida albicans reigning as the leading cause of invasive candidiasis. Given that fungi are eukaryotes like their human host, the number of unique molecular targets that can be exploited for antifungal development remains limited. Currently, there are only three major classes of drugs approved for the treatment of invasive mycoses, and the efficacy of these agents is compromised by the development of drug resistance in pathogen populations. Notably, the emergence of additional drug-resistant species, such as Candida auris and Candida glabrata, further threatens the limited armamentarium of antifungals available to treat these serious infections. Here, we describe our current arsenal of antifungals and elaborate on the resistance mechanisms Candida species possess that render them recalcitrant to therapeutic intervention. Finally, we highlight some of the most promising therapeutic strategies that may help combat antifungal resistance, including combination therapy, targeting fungal-virulence traits, and modulating host immunity. Overall, a thorough understanding of the mechanistic principles governing antifungal drug resistance is fundamental for the development of novel therapeutics to combat current and emerging fungal threats.
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Affiliation(s)
- Yunjin Lee
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
| | - Emily Puumala
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
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19
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Zhao C, Tombola F. Voltage-gated proton channels from fungi highlight role of peripheral regions in channel activation. Commun Biol 2021; 4:261. [PMID: 33637875 PMCID: PMC7910559 DOI: 10.1038/s42003-021-01792-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 02/03/2021] [Indexed: 01/31/2023] Open
Abstract
Here, we report the identification and characterization of the first proton channels from fungi. The fungal proteins are related to animal voltage-gated Hv channels and are conserved in both higher and lower fungi. Channels from Basidiomycota and Ascomycota appear to be evolutionally and functionally distinct. Representatives from the two phyla share several features with their animal counterparts, including structural organization and strong proton selectivity, but they differ from each other and from animal Hvs in terms of voltage range of activation, pharmacology, and pH sensitivity. The activation gate of Hv channels is believed to be contained within the transmembrane core of the protein and little is known about contributions of peripheral regions to the activation mechanism. Using a chimeragenesis approach, we find that intra- and extracellular peripheral regions are main determinants of the voltage range of activation in fungal channels, highlighting the role of these overlooked components in channel gating.
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Affiliation(s)
- Chang Zhao
- Department of Physiology and Biophysics, University of California, Irvine, CA, USA
- Chao Family Comprehensive Cancer Center, University of California, Irvine, CA, USA
| | - Francesco Tombola
- Department of Physiology and Biophysics, University of California, Irvine, CA, USA.
- Chao Family Comprehensive Cancer Center, University of California, Irvine, CA, USA.
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20
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Gao J, Xu X, Huang K, Liang Z. Fungal G-Protein-Coupled Receptors: A Promising Mediator of the Impact of Extracellular Signals on Biosynthesis of Ochratoxin A. Front Microbiol 2021; 12:631392. [PMID: 33643259 PMCID: PMC7907439 DOI: 10.3389/fmicb.2021.631392] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 01/21/2021] [Indexed: 01/17/2023] Open
Abstract
G-protein-coupled receptors (GPCRs) are transmembrane receptors involved in transducing signals from the external environment inside the cell, which enables fungi to coordinate cell transport, metabolism, and growth to promote their survival, reproduction, and virulence. There are 14 classes of GPCRs in fungi involved in sensing various ligands. In this paper, the synthesis of mycotoxins that are GPCR-mediated is discussed with respect to ligands, environmental stimuli, and intra-/interspecific communication. Despite their apparent importance in fungal biology, very little is known about the role of ochratoxin A (OTA) biosynthesis by Aspergillus ochraceus and the ligands that are involved. Fortunately, increasing evidence shows that the GPCR that involves the AF/ST (sterigmatocystin) pathway in fungi belongs to the same genus. Therefore, we speculate that GPCRs play an important role in a variety of environmental signals and downstream pathways in OTA biosynthesis. The verification of this inference will result in a more controllable GPCR target for control of fungal contamination in the future.
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Affiliation(s)
- Jing Gao
- Beijing Laboratory for Food Quality and Safety, Beijing, China
| | - Xinge Xu
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Kunlun Huang
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Zhihong Liang
- Beijing Laboratory for Food Quality and Safety, Beijing, China.,College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
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21
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Anti-adherence and Anti-fungal Abilities of Thymol and Carvacrol Against Candida Species Isolated From Patients with Oral Candidiasis in Comparison with Fluconazole and Voriconazole. Jundishapur J Nat Pharm Prod 2021. [DOI: 10.5812/jjnpp.65005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background: Natural isopropyl cresols, such as thymol and carvacrol, have been known to have antifungal activities. Objectives: The current study aimed to investigate the anti-adherence and antifungal activities of thymol, carvacrol, fluconazole, and voriconazole against oral isolates of Candida albicans (C. albicans), C. glabrata, and C. krusei. Methods: The susceptibility assay for the test compounds was performed using the disk diffusion method against all Candida isolates. Also, anti-adherence activity was examined using a rapid and highly reproducible 96 well microtiter-based method. Results: Both natural phenols and antifungal drugs revealed various efficacies against studied Candida species. The susceptibility to fluconazole and voriconazole were 100% for C. albicans, 50% and 90% for C. glabrata, and 0% and 100% for C. krusei isolates, respectively. The mean diameter of the inhibition zone was greater for thymol than carvacrol in C. albicans (19.89 ± 0.80 mm versus 17.05 ± 0.61 mm), C. glabrata (18.87 ± 0.71 mm versus 15.77 ± 0.57 mm), and C. krusei (15.11 ± 0.91 mm versus 13.91 ± 1.04 mm) isolates tested. Thymol showed more effective inhibition on adherence of all Candida species than other treatments. The mean relative adherence ratios for C. albicans, C. glabrata, and C. krusei were 0.50, 0.60, and 0.64, respectively. Conclusions: This study demonstrated significant inhibitory properties of thymol and carvacrol on the adherence and growth of azole susceptible- and -resistant Candida isolates. Also, thymol was more effective for preventing the adherence of yeast cells to polystyrene in comparison to carvacrol.
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Sphingolipidomics of drug resistant Candida auris clinical isolates reveal distinct sphingolipid species signatures. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1866:158815. [PMID: 32942047 PMCID: PMC7695621 DOI: 10.1016/j.bbalip.2020.158815] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 08/26/2020] [Accepted: 09/10/2020] [Indexed: 12/16/2022]
Abstract
Independent studies from our group and others have provided evidence that sphingolipids (SLs) influence the antimycotic susceptibility of Candida species. We analyzed the molecular SL signatures of drug-resistant clinical isolates of Candida auris, which have emerged as a global threat over the last decade. This included Indian hospital isolates of C. auris, which were either resistant to fluconazole (FLCR) or amphotericin B (AmBR) or both drugs. Relative to Candida glabrata and Candida albicans strains, these C. auris isolates were susceptible to SL pathway inhibitors such as myriocin and aureobasidin A, suggesting that SL content may influence azole and AmB susceptibilities. Our analysis of SLs confirmed the presence of 140 SL species within nine major SL classes, namely the sphingoid bases, Cer, αOH-Cer, dhCer, PCer, αOH-PCer, αOH-GlcCer, GlcCer, and IPC. Other than for αOH-GlcCer, most of the SLs were found at higher concentrations in FLCR isolates as compared to the AmBR isolates. SLs were at intermediate levels in FLCR + AmBR isolates. The observed diversity of molecular species of SL classes based on fatty acyl composition was further reflected in their distinct specific imprint, suggesting their influence in drug resistance. Together, the presented data improves our understanding of the dynamics of SL structures, their synthesis, and link to the drug resistance in C. auris. Candida auris isolates are susceptible to sphingolipid inhibitors myriocin and aureobasidin A. The distribution of sphingolipid species is distinct among C. auris isolates resistant to different antifungals. Phytoceramides are the most abundant class of sphingolipid. Cer(d18:1/18:1) is the major of ceramide species in C. auris. d19:2 glucosylceramide backbone is typically in abundance in AmB resistant C. auris isolates.
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Song J, Liu X, Li R. Sphingolipids: Regulators of azole drug resistance and fungal pathogenicity. Mol Microbiol 2020; 114:891-905. [PMID: 32767804 DOI: 10.1111/mmi.14586] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 07/29/2020] [Accepted: 08/02/2020] [Indexed: 12/14/2022]
Abstract
In recent years, the role of sphingolipids in pathogenic fungi, in terms of pathogenicity and resistance to azole drugs, has been a rapidly growing field. This review describes evidence about the roles of sphingolipids in azole resistance and fungal virulence. Sphingolipids can serve as signaling molecules that contribute to azole resistance through modulation of the expression of drug efflux pumps. They also contribute to azole resistance by participating in various microbial pathways such as the unfolded protein response (UPR), pH-responsive Rim pathway, and pleiotropic drug resistance (PDR) pathway. In addition, sphingolipid signaling and eisosomes also coordinately regulate sphingolipid biosynthesis in response to azole-induced membrane stress. Sphingolipids are important for fungal virulence, playing roles during growth in hosts under stressful conditions, maintenance of cell wall integrity, biofilm formation, and production of various virulence factors. Finally, we discuss the possibility of exploiting fungal sphingolipids for the development of new therapeutic strategies to treat infections caused by pathogenic fungi.
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Affiliation(s)
- Jinxing Song
- The Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province and School of Life Science, Jiangsu Normal University, Xuzhou, PR China
| | - Xiao Liu
- The Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province and School of Life Science, Jiangsu Normal University, Xuzhou, PR China
| | - Rongpeng Li
- The Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province and School of Life Science, Jiangsu Normal University, Xuzhou, PR China
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Alves R, Barata-Antunes C, Casal M, Brown AJP, Van Dijck P, Paiva S. Adapting to survive: How Candida overcomes host-imposed constraints during human colonization. PLoS Pathog 2020; 16:e1008478. [PMID: 32437438 PMCID: PMC7241708 DOI: 10.1371/journal.ppat.1008478] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Successful human colonizers such as Candida pathogens have evolved distinct strategies to survive and proliferate within the human host. These include sophisticated mechanisms to evade immune surveillance and adapt to constantly changing host microenvironments where nutrient limitation, pH fluctuations, oxygen deprivation, changes in temperature, or exposure to oxidative, nitrosative, and cationic stresses may occur. Here, we review the current knowledge and recent findings highlighting the remarkable ability of medically important Candida species to overcome a broad range of host-imposed constraints and how this directly affects their physiology and pathogenicity. We also consider the impact of these adaptation mechanisms on immune recognition, biofilm formation, and antifungal drug resistance, as these pathogens often exploit specific host constraints to establish a successful infection. Recent studies of adaptive responses to physiological niches have improved our understanding of the mechanisms established by fungal pathogens to evade the immune system and colonize the host, which may facilitate the design of innovative diagnostic tests and therapeutic approaches for Candida infections.
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Affiliation(s)
- Rosana Alves
- Centre of Molecular and Environmental Biology, University of Minho, Campus de Gualtar, Braga, Portugal
- Institute of Science and Innovation for Bio-Sustainability (IB-S) University of Minho, Campus de Gualtar, Braga, Portugal
| | - Cláudia Barata-Antunes
- Centre of Molecular and Environmental Biology, University of Minho, Campus de Gualtar, Braga, Portugal
- Institute of Science and Innovation for Bio-Sustainability (IB-S) University of Minho, Campus de Gualtar, Braga, Portugal
| | - Margarida Casal
- Centre of Molecular and Environmental Biology, University of Minho, Campus de Gualtar, Braga, Portugal
- Institute of Science and Innovation for Bio-Sustainability (IB-S) University of Minho, Campus de Gualtar, Braga, Portugal
| | | | - Patrick Van Dijck
- VIB-KU Leuven Center for Microbiology, Flanders, Belgium
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven, Belgium
| | - Sandra Paiva
- Centre of Molecular and Environmental Biology, University of Minho, Campus de Gualtar, Braga, Portugal
- Institute of Science and Innovation for Bio-Sustainability (IB-S) University of Minho, Campus de Gualtar, Braga, Portugal
- * E-mail: mailto:
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Aflatoxin Biosynthesis and Genetic Regulation: A Review. Toxins (Basel) 2020; 12:toxins12030150. [PMID: 32121226 PMCID: PMC7150809 DOI: 10.3390/toxins12030150] [Citation(s) in RCA: 134] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/27/2020] [Accepted: 02/25/2020] [Indexed: 12/15/2022] Open
Abstract
The study of fungal species evolved radically with the development of molecular techniques and produced new evidence to understand specific fungal mechanisms such as the production of toxic secondary metabolites. Taking advantage of these technologies to improve food safety, the molecular study of toxinogenic species can help elucidate the mechanisms underlying toxin production and enable the development of new effective strategies to control fungal toxicity. Numerous studies have been made on genes involved in aflatoxin B1 (AFB1) production, one of the most hazardous carcinogenic toxins for humans and animals. The current review presents the roles of these different genes and their possible impact on AFB1 production. We focus on the toxinogenic strains Aspergillus flavus and A. parasiticus, primary contaminants and major producers of AFB1 in crops. However, genetic reports on A. nidulans are also included because of the capacity of this fungus to produce sterigmatocystin, the penultimate stable metabolite during AFB1 production. The aim of this review is to provide a general overview of the AFB1 enzymatic biosynthesis pathway and its link with the genes belonging to the AFB1 cluster. It also aims to illustrate the role of global environmental factors on aflatoxin production and the recent data that demonstrate an interconnection between genes regulated by these environmental signals and aflatoxin biosynthetic pathway.
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The genome of opportunistic fungal pathogen Fusarium oxysporum carries a unique set of lineage-specific chromosomes. Commun Biol 2020; 3:50. [PMID: 32005944 PMCID: PMC6994591 DOI: 10.1038/s42003-020-0770-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 01/10/2020] [Indexed: 12/12/2022] Open
Abstract
Fusarium oxysporum is a cross-kingdom fungal pathogen that infects plants and humans. Horizontally transferred lineage-specific (LS) chromosomes were reported to determine host-specific pathogenicity among phytopathogenic F. oxysporum. However, the existence and functional importance of LS chromosomes among human pathogenic isolates are unknown. Here we report four unique LS chromosomes in a human pathogenic strain NRRL 32931, isolated from a leukemia patient. These LS chromosomes were devoid of housekeeping genes, but were significantly enriched in genes encoding metal ion transporters and cation transporters. Homologs of NRRL 32931 LS genes, including a homolog of ceruloplasmin and the genes that contribute to the expansion of the alkaline pH-responsive transcription factor PacC/Rim1p, were also present in the genome of NRRL 47514, a strain associated with Fusarium keratitis outbreak. This study provides the first evidence, to our knowledge, for genomic compartmentalization in two human pathogenic fungal genomes and suggests an important role of LS chromosomes in niche adaptation. Zhang, Yang et al. compare a Fusarium oxysporum isolate obtained clinically to a phytopathogenic strain to examine transfer of lineage-specific chromosomes in determining host specificity. They find four unique lineage-specific chromosomes that seem to contribute to fungal adaptation to human hosts.
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Abstract
G-protein-coupled receptors (GPCRs) are the largest family of transmembrane receptors in fungi. These receptors have an important role in the transduction of extracellular signals into intracellular sites in response to diverse stimuli. They enable fungi to coordinate cell function and metabolism, thereby promoting their survival and propagation, and sense certain fundamentally conserved elements, such as nutrients, pheromones, and stress, for adaptation to their niches, environmental stresses, and host environment, causing disease and pathogen virulence. This chapter highlights the role of GPCRs in fungi in coordinating cell function and metabolism. Fungal cells sense the molecular interactions between extracellular signals. Their respective sensory systems are described here in detail.
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Affiliation(s)
- Abd El-Latif Hesham
- Department of Genetics Faculty of Agriculture, Beni-Suef University, Beni-Suef, Egypt
| | | | | | | | - Vijai Kumar Gupta
- AgroBioSciences and Chemical & Biochemical Sciences Department, University Mohammed VI Polytechnic (UM6P), Benguerir, Morocco
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Banguela-Castillo A, Ramos-González PL, Peña-Marey M, Godoy CV, Harakava R. An updated phylogenetic classification of Corynespora cassiicola isolates and a practical approach to their identification based on the nucleotide polymorphisms at the ga4 and caa5 loci. Mycologia 2019; 112:24-38. [PMID: 31750788 DOI: 10.1080/00275514.2019.1670018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Corynespora cassiicola (Burk. & M.A. Curtis) C.T. Wei. is an anamorphic fungus that affects more than 530 plant species, including economically important crops. Several lineages of this pathogen have been recognized, but the classification of isolates into clades is time-consuming and still sometimes leads to unclear results. In this work, eight major phylogenetic clades (PhL1-PhL8) including 245 isolates of C. cassiicola from 44 plant species were established based on a Bayesian inference analysis of four combined C. cassiicola genomic loci retrieved from GenBank, i.e., rDNA internal transcribed spacer (ITS), actin-1,ga4, and caa5. The existence of PhL1-PhL5 and PhL7 as clonal lineages was further confirmed through the analysis of full-genome single-nucleotide polymorphisms of 39 isolates. Haplotypes of the caa5 locus were PhL specific and encode isoforms of the LDB19 domain of a putative α-arrestin N-terminal-like protein. Evolution of the Caa5 arrestin is in correspondence with the PhLs. ga4 and caa5 PhL consensus sequences and a cleaved amplified polymorphic sequence (CAPS) procedure were generated based on the conserved nucleotide sequences and enzyme restriction patterns observed among isolates from the same lineage, respectively. The CAPS method was validated in silico, and its practical use allowed us to differentiate between tomato and papaya isolates, as well as to reveal the prevalence of PhL1 among isolates infecting soybean in Brazil. This novel approach could be useful in the efforts to control the diseases associated with C. cassiicola.
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Affiliation(s)
- Alexander Banguela-Castillo
- Phytopathology and Plant Biochemistry Laboratory, Instituto Biológico de São Paulo, Avenida Conselheiro Rodrigues Alves, 1252 Vila Mariana, CEP 04014-900, São Paulo, São Paulo, Brazil
| | - Pedro L Ramos-González
- Phytopathology and Plant Biochemistry Laboratory, Instituto Biológico de São Paulo, Avenida Conselheiro Rodrigues Alves, 1252 Vila Mariana, CEP 04014-900, São Paulo, São Paulo, Brazil
| | - Mabel Peña-Marey
- Microbiology and Bacteriology Laboratory, St. Joseph's Hospital, 3001 W Martin Luther King Jr. Boulevard, Tampa, Florida 33607.,Instituto de Investigaciones en Fruticultura Tropical, Avenida 7ma 3005, Playa, La Habana 10500, Cuba
| | - Claudia V Godoy
- Embrapa Soja, Rodovia Carlos João Strass, s/nº Acesso Orlando Amaral, Distrito de Warta Caixa, Postal: 231, CEP: 86001-970, Londrina, Paraná, Brazil
| | - Ricardo Harakava
- Phytopathology and Plant Biochemistry Laboratory, Instituto Biológico de São Paulo, Avenida Conselheiro Rodrigues Alves, 1252 Vila Mariana, CEP 04014-900, São Paulo, São Paulo, Brazil
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MaPacC, a pH-responsive transcription factor, negatively regulates thermotolerance and contributes to conidiation and virulence in Metarhizium acridum. Curr Genet 2019; 66:397-408. [DOI: 10.1007/s00294-019-01032-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 08/13/2019] [Accepted: 08/20/2019] [Indexed: 12/15/2022]
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The pH sensing receptor AopalH plays important roles in the nematophagous fungus Arthrobotrys oligospora. Fungal Biol 2019; 123:547-554. [PMID: 31196524 DOI: 10.1016/j.funbio.2019.05.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 04/24/2019] [Accepted: 05/09/2019] [Indexed: 01/01/2023]
Abstract
There is well-conserved PacC/Rim101 signaling among ascomycete fungi to mediate environmental pH sensing. For pathogenic fungi, this pathway not only enables fungi to grow over a wide pH range, but it also determines whether these fungi can successfully colonize and invade the targeted host. Within the pal/PacC pathway, palH is a putative ambient pH sensor with a seven-transmembrane domain. To characterize the function of a palH homolog, AopalH, in the nematophagous fungus Arthrobotrys oligospora, we knocked out the encoding gene of AopalH through homologous recombination, and the transformants exhibited slower growth rates, greater sensitivities to cationic and hyperoxidation stresses, as well as reduced conidiation and reduced trap formation, suggesting that the pH regulatory system has critical functions in nematophagous fungi. Our results provide novel insights into the mechanisms of pH response and regulation in fungi.
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Emerging Mechanisms of Drug Resistance in Candida albicans. YEASTS IN BIOTECHNOLOGY AND HUMAN HEALTH 2019; 58:135-153. [DOI: 10.1007/978-3-030-13035-0_6] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Cervantes-Montelongo JA, Ruiz-Herrera J. Identification of a novel member of the pH responsive pathway Pal/Rim in Ustilago maydis. J Basic Microbiol 2018; 59:14-23. [PMID: 30357888 DOI: 10.1002/jobm.201800180] [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] [Received: 04/22/2018] [Revised: 09/25/2018] [Accepted: 09/29/2018] [Indexed: 11/05/2022]
Abstract
The most important signal transduction mechanism related to environmental pH responses in fungi is the Pal/Rim pathway. Our knowledge of this pathway came initially from studies on Ascomycota species where it is made by seven members divided into two complexes, one located at the plasma membrane, and other at the endosomal membrane. In Basidiomycota sepecies only the homologs of the endosomal membrane complex (genes PalA/Rim20, PalB/ Rim13, and PalC/ Rim23), plus the transcription factor PacC/Rim101 have been identified. In this study, we describe the identification in Ustilago maydis of a gene encoding a Rho-like protein (tentatively named RHO4) as a novel member of this pathway. The RHO4 gene possibly plays, among other functions, a role in the second proteolytic cleavage that leads to the activation of the transcription factor PacC/Rim101. Mutants in this gene showed a pleiotropic phenotype, displaying similar characteristics to the Pal/Rim mutants, such as a lower growth rate at alkaline pH, high sensitivity to ionic and osmotic stresses, and impairment in protease secretion, but no alteration of the yeast-to-mycelium dimorphic transition induced by acid pH whereas it has a function in the dimorphic transition induced by fatty acids.
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Affiliation(s)
- Juan A Cervantes-Montelongo
- Departamento de Ingeniería Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Irapuato Gto., México
| | - José Ruiz-Herrera
- Departamento de Ingeniería Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Irapuato Gto., México
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Rascle C, Dieryckx C, Dupuy JW, Muszkieta L, Souibgui E, Droux M, Bruel C, Girard V, Poussereau N. The pH regulator PacC: a host-dependent virulence factor in Botrytis cinerea. ENVIRONMENTAL MICROBIOLOGY REPORTS 2018; 10:555-568. [PMID: 30066486 DOI: 10.1111/1758-2229.12663] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 05/21/2018] [Indexed: 05/29/2023]
Abstract
The phytopathogenic fungus Botrytis cinerea is able to infect a wide variety of plants and plant tissues with differing chemical compositions. During its interaction with the host, this pathogen modulates its ambient pH by secreting acids or ammonia. In this work, we examined the Pal/Pac pathway, the fungal ambient pH-responsive signalling circuit, and investigated the role of the PacC transcription factor. Characterization of the BcpacC deletion mutant revealed an alteration of both fungal growth and virulence depending on the pH of the culture medium or of the host tissue. The pathogenicity of the mutant was altered on plants exhibiting a neutral pH and not on plants with acidic tissues. The capacity of the mutant to acidify its environment and, more particularly, to produce oxalic acid was affected, as was production of reactive oxygen species. Finally, proteomic profiling of the mutant secretome revealed significant changes in plant cell wall polysaccharides proteins and lipid degradation and oxidoreduction, highlighting the importance of BcPacC in the necrotrophic lifestyle of B. cinerea.
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Affiliation(s)
- Christine Rascle
- Univ Lyon, Université Lyon 1, CNRS, Bayer SAS, UMR5240, Microbiologie, Adaptation, Pathogénie, 14-18 impasse P. Baizet, F-69009, LYON, France
| | - Cindy Dieryckx
- Univ Lyon, Université Lyon 1, CNRS, Bayer SAS, UMR5240, Microbiologie, Adaptation, Pathogénie, 14-18 impasse P. Baizet, F-69009, LYON, France
| | - Jean William Dupuy
- Plateforme protéome, Centre de Génomique Fonctionnelle, Université de Bordeaux, Bordeaux, France
| | - Laetitia Muszkieta
- Univ Lyon, Université Lyon 1, CNRS, Bayer SAS, UMR5240, Microbiologie, Adaptation, Pathogénie, 14-18 impasse P. Baizet, F-69009, LYON, France
| | - Eytham Souibgui
- Univ Lyon, Université Lyon 1, CNRS, Bayer SAS, UMR5240, Microbiologie, Adaptation, Pathogénie, 14-18 impasse P. Baizet, F-69009, LYON, France
| | - Michel Droux
- Univ Lyon, Université Lyon 1, CNRS, Bayer SAS, UMR5240, Microbiologie, Adaptation, Pathogénie, 14-18 impasse P. Baizet, F-69009, LYON, France
| | - Christophe Bruel
- Univ Lyon, Université Lyon 1, CNRS, Bayer SAS, UMR5240, Microbiologie, Adaptation, Pathogénie, 14-18 impasse P. Baizet, F-69009, LYON, France
| | - Vincent Girard
- Univ Lyon, Université Lyon 1, CNRS, Bayer SAS, UMR5240, Microbiologie, Adaptation, Pathogénie, 14-18 impasse P. Baizet, F-69009, LYON, France
| | - Nathalie Poussereau
- Univ Lyon, Université Lyon 1, CNRS, Bayer SAS, UMR5240, Microbiologie, Adaptation, Pathogénie, 14-18 impasse P. Baizet, F-69009, LYON, France
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Li Y, Sun L, Lu C, Gong Y, Li M, Sun S. Promising Antifungal Targets Against Candida albicans Based on Ion Homeostasis. Front Cell Infect Microbiol 2018; 8:286. [PMID: 30234023 PMCID: PMC6131588 DOI: 10.3389/fcimb.2018.00286] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 07/27/2018] [Indexed: 11/13/2022] Open
Abstract
In recent decades, invasive fungal infections have been increasing significantly, contributing to high incidences and mortality in immunosuppressed patients. Candida albicans (C. albicans) is the most prevalent opportunistic fungal pathogen in humans that can cause severe and often fatal bloodstream infections. Current antifungal agents have several limitations, including that only a small number of classes of antifungals are available, certain of which have severe toxicity and high cost. Moreover, the emergence of drug resistance is a new limitation to successful patient outcomes. Therefore, the development of antifungals with novel targets is an essential strategy for the efficient management of C. albicans infections. It is widely recognized that ion homeostasis is crucial for all living cells. Many studies have identified that ion-signaling and transduction networks are central to fungal survival by regulating gene expression, morphological transition, host invasion, stress response, and drug resistance. Dysregulation of ion homeostasis rapidly mediates cell death, forming the mechanistic basis of a growing number of compounds that elicit antifungal activity. Most of the potent antifungals have been widely used in the clinic, and certain of them have low toxicity, meaning that they may be expected to be used as antifungal drugs in the future. Hence, we briefly summarize the homeostasis regulation of several important ions, potential antifungal targets based on these ion-signaling networks, and antifungal compounds based on the disruption of ion homeostasis. This summary will help in designing effective drugs and identifying new targets for combating fungal diseases.
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Affiliation(s)
- Yiman Li
- School of Pharmaceutical Sciences, Shandong University, Jinan, China
| | - Licui Sun
- Department of Pharmacy, Feicheng Mining Central Hospital, Feicheng, China
| | - Chunyan Lu
- Department of Pharmacy, Qianfoshan Hospital Affiliated to Shandong University, Jinan, China
| | - Ying Gong
- School of Pharmaceutical Sciences, Shandong University, Jinan, China
| | - Min Li
- Department of Pharmacy, Qianfoshan Hospital Affiliated to Shandong University, Jinan, China
| | - Shujuan Sun
- Department of Pharmacy, Qianfoshan Hospital Affiliated to Shandong University, Jinan, China
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Luo Z, Zhang T, Liu P, Bai Y, Chen Q, Zhang Y, Keyhani NO. The Beauveria bassiana Gas3 β-Glucanosyltransferase Contributes to Fungal Adaptation to Extreme Alkaline Conditions. Appl Environ Microbiol 2018; 84:e01086-18. [PMID: 29802184 PMCID: PMC6052264 DOI: 10.1128/aem.01086-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 05/17/2018] [Indexed: 12/20/2022] Open
Abstract
Fungal β-1,3-glucanosyltransferases are cell wall-remodeling enzymes implicated in stress response, cell wall integrity, and virulence, with most fungal genomes containing multiple members. The insect-pathogenic fungus Beauveria bassiana displays robust growth over a wide pH range (pH 4 to 10). A random insertion mutant library screening for increased sensitivity to alkaline (pH 10) growth conditions resulted in the identification and mapping of a mutant to a β-1,3-glucanosyltransferase gene (Bbgas3). Bbgas3 expression was pH dependent and regulated by the PacC transcription factor, which activates genes in response to neutral/alkaline growth conditions. Targeted gene knockout of Bbgas3 resulted in reduced growth under alkaline conditions, with only minor effects of increased sensitivity to cell wall stress (Congo red and calcofluor white) and no significant effects on fungal sensitivity to oxidative or osmotic stress. The cell walls of ΔBbgas3 aerial conidia were thinner than those of the wild-type and complemented strains in response to alkaline conditions, and β-1,3-glucan antibody and lectin staining revealed alterations in cell surface carbohydrate epitopes. The ΔBbgas3 mutant displayed alterations in cell wall chitin and carbohydrate content in response to alkaline pH. Insect bioassays revealed impaired virulence for the ΔBbgas3 mutant depending upon the pH of the media on which the conidia were grown and harvested. Unexpectedly, a decreased median lethal time to kill (LT50, i.e., increased virulence) was seen for the mutant using intrahemocoel injection assays using conidia grown at acidic pH (5.6). These data show that BbGas3 acts as a pH-responsive cell wall-remodeling enzyme involved in resistance to extreme pH (>9).IMPORTANCE Little is known about adaptations required for growth at high (>9) pH. Here, we show that a specific fungal membrane-remodeling β-1,3-glucanosyltransferase gene (Bbgas3) regulated by the pH-responsive PacC transcription factor forms a critical aspect of the ability of the insect-pathogenic fungus Beauveria bassiana to grow at extreme pH. The loss of Bbgas3 resulted in a unique decreased ability to grow at high pH, with little to no effects seen with respect to other stress conditions, i.e., cell wall integrity and osmotic and oxidative stress. However, pH-dependent alternations in cell wall properties and virulence were noted for the ΔBbgas3 mutant. These data provide a mechanistic insight into the importance of the specific cell wall structure required to stabilize the cell at high pH and link it to the PacC/Pal/Rim pH-sensing and regulatory system.
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Affiliation(s)
- Zhibing Luo
- Academy of Agricultural Sciences, Southwest University, Chongqing, People's Republic of China
- Biotechnology Research Center, Southwest University, Chongqing, People's Republic of China
| | - Tongbing Zhang
- Academy of Agricultural Sciences, Southwest University, Chongqing, People's Republic of China
- Biotechnology Research Center, Southwest University, Chongqing, People's Republic of China
| | - Pengfei Liu
- Academy of Agricultural Sciences, Southwest University, Chongqing, People's Republic of China
- Biotechnology Research Center, Southwest University, Chongqing, People's Republic of China
| | - Yuting Bai
- Academy of Agricultural Sciences, Southwest University, Chongqing, People's Republic of China
- Biotechnology Research Center, Southwest University, Chongqing, People's Republic of China
| | - Qiyan Chen
- Academy of Agricultural Sciences, Southwest University, Chongqing, People's Republic of China
- Biotechnology Research Center, Southwest University, Chongqing, People's Republic of China
| | - Yongjun Zhang
- Academy of Agricultural Sciences, Southwest University, Chongqing, People's Republic of China
- Biotechnology Research Center, Southwest University, Chongqing, People's Republic of China
| | - Nemat O Keyhani
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
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Brown HE, Ost KS, Esher SK, Pianalto KM, Saelens JW, Guan Z, Andrew Alspaugh J. Identifying a novel connection between the fungal plasma membrane and pH-sensing. Mol Microbiol 2018; 109:474-493. [PMID: 29885030 PMCID: PMC6173979 DOI: 10.1111/mmi.13998] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2018] [Indexed: 01/11/2023]
Abstract
The mechanisms by which micro-organisms sense and internalize extracellular pH signals are not completely understood. One example of a known external pH-sensing process is the fungal-specific Rim/Pal signal transduction pathway. Fungi, such as the opportunistic pathogen Cryptococcus neoformans, use Rim signaling to sense and respond to changes in environmental pH. Mutations in this pathway result in strains that are attenuated for survival at alkaline pH, and often for survival within the host. Here, we used an insertional mutagenesis screen to identify novel genes required for C. neoformans growth at host pH. We discovered altered alkaline pH growth in several strains with specific defects in plasma membrane composition and maintenance of phospholipid assembly. Among these, loss of function of the Cdc50 lipid flippase regulatory subunit affected the temporal dynamics of Rim pathway activation. We defined distinct and overlapping cellular processes regulated by Rim101 and Cdc50 through analysis of the transcriptome in these mutant strains. We further explored how pH-induced membrane changes affect membrane-bound pH-sensing proteins, specifically the C-terminal domain of the Rra1 protein, an upstream Rim pathway activator and pH sensor. These results suggest both broadly applicable and phylum-specific molecular interactions that drive microbial environmental sensing.
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Affiliation(s)
- Hannah E Brown
- Departments of Molecular Genetics and Microbiology/Medicine, Duke University School of Medicine, Durham, NC, USA
| | - Kyla S Ost
- Departments of Molecular Genetics and Microbiology/Medicine, Duke University School of Medicine, Durham, NC, USA
| | - Shannon K Esher
- Departments of Molecular Genetics and Microbiology/Medicine, Duke University School of Medicine, Durham, NC, USA
| | - Kaila M Pianalto
- Departments of Molecular Genetics and Microbiology/Medicine, Duke University School of Medicine, Durham, NC, USA
| | - Joseph W Saelens
- Departments of Molecular Genetics and Microbiology/Medicine, Duke University School of Medicine, Durham, NC, USA
| | - Ziqiang Guan
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - J Andrew Alspaugh
- Departments of Molecular Genetics and Microbiology/Medicine, Duke University School of Medicine, Durham, NC, USA
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Van Dijck P, Sjollema J, Cammue BPA, Lagrou K, Berman J, d’Enfert C, Andes DR, Arendrup MC, Brakhage AA, Calderone R, Cantón E, Coenye T, Cos P, Cowen LE, Edgerton M, Espinel-Ingroff A, Filler SG, Ghannoum M, Gow NA, Haas H, Jabra-Rizk MA, Johnson EM, Lockhart SR, Lopez-Ribot JL, Maertens J, Munro CA, Nett JE, Nobile CJ, Pfaller MA, Ramage G, Sanglard D, Sanguinetti M, Spriet I, Verweij PE, Warris A, Wauters J, Yeaman MR, Zaat SA, Thevissen K. Methodologies for in vitro and in vivo evaluation of efficacy of antifungal and antibiofilm agents and surface coatings against fungal biofilms. MICROBIAL CELL (GRAZ, AUSTRIA) 2018; 5:300-326. [PMID: 29992128 PMCID: PMC6035839 DOI: 10.15698/mic2018.07.638] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 05/24/2018] [Indexed: 12/13/2022]
Abstract
Unlike superficial fungal infections of the skin and nails, which are the most common fungal diseases in humans, invasive fungal infections carry high morbidity and mortality, particularly those associated with biofilm formation on indwelling medical devices. Therapeutic management of these complex diseases is often complicated by the rise in resistance to the commonly used antifungal agents. Therefore, the availability of accurate susceptibility testing methods for determining antifungal resistance, as well as discovery of novel antifungal and antibiofilm agents, are key priorities in medical mycology research. To direct advancements in this field, here we present an overview of the methods currently available for determining (i) the susceptibility or resistance of fungal isolates or biofilms to antifungal or antibiofilm compounds and compound combinations; (ii) the in vivo efficacy of antifungal and antibiofilm compounds and compound combinations; and (iii) the in vitro and in vivo performance of anti-infective coatings and materials to prevent fungal biofilm-based infections.
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Affiliation(s)
- Patrick Van Dijck
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
- KU Leuven Laboratory of Molecular Cell Biology, Leuven, Belgium
| | - Jelmer Sjollema
- University of Groningen, University Medical Center Groningen, Department of BioMedical Engineering, Groningen, The Netherlands
| | - Bruno P. A. Cammue
- Centre for Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
- Department of Plant Systems Biology, VIB, Ghent, Belgium
| | - Katrien Lagrou
- Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium
- Clinical Department of Laboratory Medicine and National Reference Center for Mycosis, UZ Leuven, Belgium
| | - Judith Berman
- School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Israel
| | - Christophe d’Enfert
- Institut Pasteur, INRA, Unité Biologie et Pathogénicité Fongiques, Paris, France
| | - David R. Andes
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Maiken C. Arendrup
- Unit of Mycology, Statens Serum Institut, Copenhagen, Denmark
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Axel A. Brakhage
- Leibniz Institute for Natural Product Research and Infection Biology - Hans Knoell Institute (HKI), Dept. Microbiology and Molecular Biology, Friedrich Schiller University Jena, Institute of Microbiology, Jena, Germany
| | - Richard Calderone
- Department of Microbiology & Immunology, Georgetown University Medical Center, Washington DC, USA
| | - Emilia Cantón
- Severe Infection Research Group: Medical Research Institute La Fe (IISLaFe), Valencia, Spain
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
- ESCMID Study Group for Biofilms, Switzerland
| | - Paul Cos
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Belgium
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Mira Edgerton
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, Buffalo, NY USA
| | | | - Scott G. Filler
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Mahmoud Ghannoum
- Center for Medical Mycology, Department of Dermatology, University Hospitals Cleveland Medical Center and Case Western Re-serve University, Cleveland, OH, USA
| | - Neil A.R. Gow
- MRC Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Hubertus Haas
- Biocenter - Division of Molecular Biology, Medical University Innsbruck, Innsbruck, Austria
| | - Mary Ann Jabra-Rizk
- Department of Oncology and Diagnostic Sciences, School of Dentistry; Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, USA
| | - Elizabeth M. Johnson
- National Infection Service, Public Health England, Mycology Reference Laboratory, Bristol, UK
| | | | | | - Johan Maertens
- Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium and Clinical Department of Haematology, UZ Leuven, Leuven, Belgium
| | - Carol A. Munro
- MRC Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Jeniel E. Nett
- University of Wisconsin-Madison, Departments of Medicine and Medical Microbiology & Immunology, Madison, WI, USA
| | - Clarissa J. Nobile
- Department of Molecular and Cell Biology, School of Natural Sciences, University of California, Merced, Merced, USA
| | - Michael A. Pfaller
- Departments of Pathology and Epidemiology, University of Iowa, Iowa, USA
- JMI Laboratories, North Liberty, Iowa, USA
| | - Gordon Ramage
- ESCMID Study Group for Biofilms, Switzerland
- College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - Dominique Sanglard
- Institute of Microbiology, University of Lausanne and University Hospital, CH-1011 Lausanne
| | - Maurizio Sanguinetti
- Institute of Microbiology, Università Cattolica del Sacro Cuore, IRCCS-Fondazione Policlinico "Agostino Gemelli", Rome, Italy
| | - Isabel Spriet
- Pharmacy Dpt, University Hospitals Leuven and Clinical Pharmacology and Pharmacotherapy, Dpt. of Pharmaceutical and Pharma-cological Sciences, KU Leuven, Belgium
| | - Paul E. Verweij
- Center of Expertise in Mycology Radboudumc/CWZ, Radboud University Medical Center, Nijmegen, the Netherlands (omit "Nijmegen" in Radboud University Medical Center)
| | - Adilia Warris
- MRC Centre for Medical Mycology, Aberdeen Fungal Group, University of Aberdeen, Foresterhill, Aberdeen, UK
| | - Joost Wauters
- KU Leuven-University of Leuven, University Hospitals Leuven, Department of General Internal Medicine, Herestraat 49, B-3000 Leuven, Belgium
| | - Michael R. Yeaman
- Geffen School of Medicine at the University of California, Los Angeles, Divisions of Molecular Medicine & Infectious Diseases, Har-bor-UCLA Medical Center, LABioMed at Harbor-UCLA Medical Center
| | - Sebastian A.J. Zaat
- Department of Medical Microbiology, Amsterdam Infection and Immunity Institute, Academic Medical Center, University of Am-sterdam, Netherlands
| | - Karin Thevissen
- Centre for Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
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Pianalto KM, Ost KS, Brown HE, Alspaugh JA. Characterization of additional components of the environmental pH-sensing complex in the pathogenic fungus Cryptococcus neoformans. J Biol Chem 2018; 293:9995-10008. [PMID: 29769315 DOI: 10.1074/jbc.ra118.002741] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 05/10/2018] [Indexed: 11/06/2022] Open
Abstract
Pathogenic microorganisms must adapt to changes in their immediate surroundings, including alterations in pH, to survive the shift from the external environment to that of the infected host. In the basidiomycete fungal pathogen Cryptococcus neoformans, these pH changes are primarily sensed by the fungus-specific, alkaline pH-sensing Rim/Pal pathway. The C. neoformans Rim pathway has diverged significantly from that described in ascomycete fungi. We recently identified the C. neoformans putative pH sensor Rra1, which activates the Rim pathway in response to elevated pH. In this study, we probed the function of Rra1 by analyzing its cellular localization and performing protein co-immunoprecipitation to identify potential Rra1 interactors. We found that Rra1 does not strongly colocalize or interact with immediate downstream Rim pathway components. However, these experiments identified a novel Rra1 interactor, the previously uncharacterized C. neoformans nucleosome assembly protein 1 (Nap1), which was required for Rim pathway activation. We observed that Nap1 specifically binds to the C-terminal tail of the Rra1 sensor, probably promoting Rra1 protein stability. This function of Nap1 is conserved in fungi closely related to C. neoformans that contain Rra1 orthologs, but not in the more distantly related ascomycete fungus Saccharomyces cerevisiae In conclusion, our findings have revealed the sophisticated, yet distinct, molecular mechanisms by which closely and distantly related microbial phyla rapidly adapt to environmental signals and changes, such as alterations in pH.
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Affiliation(s)
| | - Kyla S Ost
- From the Departments of Molecular Genetics and Microbiology and
| | - Hannah E Brown
- From the Departments of Molecular Genetics and Microbiology and
| | - J Andrew Alspaugh
- From the Departments of Molecular Genetics and Microbiology and .,Medicine, Duke University School of Medicine, Durham, North Carolina 27710
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39
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Sharifzadeh A, Khosravi AR, Shokri H, Shirzadi H. Potential effect of 2-isopropyl-5-methylphenol (thymol) alone and in combination with fluconazole against clinical isolates of Candida albicans, C. glabrata and C. krusei. J Mycol Med 2018; 28:294-299. [PMID: 29661606 DOI: 10.1016/j.mycmed.2018.04.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 01/06/2023]
Abstract
Limitations of antifungals used in the treatment of candidiasis, as the development of resistant strains, are known by the scientific community. In this context, the aim of this study was to investigate the activity of 2-isopropyl-5-methylphenol (thymol) in combination with fluconazole (FLZ) against clinical Candida strains. The antifungal activity of thymol along with FLZ was evaluated by the Clinical Laboratory Standards Institute (CLSI) M27-A2 broth microdilution method. In addition, synergism was observed for clinical strains of Candida spp. with combination of thymol-FLZ evaluated by the chequerboard microdilution method. The mean of minimum inhibitory concentration (MIC) values of thymol and FLZ were 49.37 and 0.475μg/ml for C. albicans, 51.25 and 18.80μg/ml for C. glabrata and 70 and 179.20μg/ml for C. krusei strains, respectively. Thymol in combination with FLZ exhibited the synergistic effects against all species of Candida tested. FICI values for thymol plus FLZ ranged from 0.366 to 0.607 for C. albicans strains, 0.367 to 0.482 for C. glabrata strains, and 0.375 to 0.563 for C. krusei strains. No antagonistic activity was seen in the strains tested. Thymol was found to have a fungicidal effect on Candida species and a synergistic effect when combined with FLZ.
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Affiliation(s)
- A Sharifzadeh
- Mycology Research Center, Faculty of Veterinary Medicine, University of Tehran, Azadi street, Tehran, Iran.
| | - A R Khosravi
- Mycology Research Center, Faculty of Veterinary Medicine, University of Tehran, Azadi street, Tehran, Iran
| | - H Shokri
- Department of Pathobiology, Faculty of Veterinary Medicine, Amol University of Special Modern Technologies, Amol, Iran
| | - H Shirzadi
- Mycology Research Center, Faculty of Veterinary Medicine, University of Tehran, Azadi street, Tehran, Iran
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40
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Xu X, Liu T, Yang J, Chen L, Liu B, Wang L, Jin Q. The First Whole-Cell Proteome- and Lysine-Acetylome-Based Comparison between Trichophyton rubrum Conidial and Mycelial Stages. J Proteome Res 2018; 17:1436-1451. [PMID: 29564889 DOI: 10.1021/acs.jproteome.7b00793] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Trichophyton rubrum is the most common fungal pathogen in the world, which has been studied as an important dermatophyte model organism. Despite the prevalence of T. rubrum, the available antifungal therapies are not sufficiently efficient. In this study, we performed the first comparison between the two major growth stages of T. rubrum: conidial and mycelial stages, based on their whole-cell proteomes and lysine acetylomes. In total, 4343 proteins were identified in both stages, and 1879 proteins were identified as differentially expressed between the two stages. The results showed that secretory proteases were more abundant in conidia, while aerobic metabolism and protein synthesis were significantly activated in the mycelial stage. In addition, 386 acetylated sites on 285 proteins and 5414 acetylated sites on 2335 proteins were identified in conidia and mycelia, respectively. The acetylation modifications were highly involved in metabolism and protein synthesis in both stages but differentially involved in Kyoto Encyclopedia of Genes and Genomes pathways and in epigenetic regulation between the two stages. Furthermore, inhibition of acetyltransferases or deacetylases significantly inhibited fungal growth and induced apoptosis. These results will enhance our understanding of the biological and physiological characteristics of T. rubrum and facilitate the development of improved therapies targeting these medically important pathogenic fungi.
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Affiliation(s)
- Xingye Xu
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology , Chinese Academy of Medical Sciences & Peking Union Medical College , Beijing 100730 , China
| | - Tao Liu
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology , Chinese Academy of Medical Sciences & Peking Union Medical College , Beijing 100730 , China
| | - Jian Yang
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology , Chinese Academy of Medical Sciences & Peking Union Medical College , Beijing 100730 , China
| | - Lihong Chen
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology , Chinese Academy of Medical Sciences & Peking Union Medical College , Beijing 100730 , China
| | - Bo Liu
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology , Chinese Academy of Medical Sciences & Peking Union Medical College , Beijing 100730 , China
| | - Lingling Wang
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology , Chinese Academy of Medical Sciences & Peking Union Medical College , Beijing 100730 , China
| | - Qi Jin
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology , Chinese Academy of Medical Sciences & Peking Union Medical College , Beijing 100730 , China
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41
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The Rim Pathway Mediates Antifungal Tolerance in Candida albicans through Newly Identified Rim101 Transcriptional Targets, Including Hsp90 and Ipt1. Antimicrob Agents Chemother 2018; 62:AAC.01785-17. [PMID: 29311085 DOI: 10.1128/aac.01785-17] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 12/19/2017] [Indexed: 12/13/2022] Open
Abstract
Invasive candidiasis (IC) is a major cause of morbidity and mortality despite antifungal treatment. Azoles and echinocandins are used as first-line therapies for IC. However, their efficacy is limited by yeast tolerance and the emergence of acquired resistance. Tolerance is a reversible stage created due to the yeast's capacity to counter antifungal drug exposure, leading to persistent growth. For Candida albicans, multiple stress signaling pathways have been shown to contribute to this adaptation. Among them, the pH-responsive Rim pathway, through its transcription factor Rim101p, was shown to mediate azole and echinocandin tolerance. The Rim pathway is fungus specific, is conserved among the members of the fungal kingdom, and plays a key role in pathogenesis and virulence. The present study aimed at confirming the role of Rim101p and investigating the implication of the other Rim proteins in antifungal tolerance in C. albicans, as well as the mechanisms underlying it. Time-kill curve experiments and colony formation tests showed that genetic inhibition of all the Rim factors enhances echinocandin and azole antifungal activity. Through RNA sequencing analysis of a rim101-/- mutant, a strain constitutively overexpressing RIM101, and control strains, we discovered novel Rim-dependent genes involved in tolerance, including HSP90, encoding a major molecular chaperone, and IPT1, involved in sphingolipid biosynthesis. Rim mutants were also hypersensitive to pharmacological inhibition of Hsp90. Taken together, these data suggest that Rim101 acts upstream of Hsp90 and that targeting the Rim pathway in combination with existing antifungal drugs may represent a promising antifungal strategy to indirectly but specifically target Hsp90 in yeasts.
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Sephton-Clark PCS, Voelz K. Spore Germination of Pathogenic Filamentous Fungi. ADVANCES IN APPLIED MICROBIOLOGY 2017; 102:117-157. [PMID: 29680124 DOI: 10.1016/bs.aambs.2017.10.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Fungi, algae, plants, protozoa, and bacteria are all known to form spores, especially hardy and ubiquitous propagation structures that are also often the infectious agents of diseases. Spores can survive for thousands of years, frozen in the permafrost (Kochkina et al., 2012), with the oldest viable spores extracted after 250 million years from salt crystals (Vreeland, Rosenzweig, & Powers, 2000). Their resistance to high levels of UV, desiccation, pressure, heat, and cold enables the survival of spores in the harshest conditions (Setlow, 2016). For example, Bacillus subtilis spores can survive and remain viable after experiencing conditions similar to those on Mars (Horneck et al., 2012). Spores are disseminated through environmental factors. Wind, water, or animal carriage allow spores to be spread ubiquitously throughout the environment. Spores will break dormancy and begin to germinate once exposed to favorable conditions. Germination is the mechanism that converts the spore from a dormant biological organism to one that grows vegetatively and is capable of either sexual or asexual reproduction. The process of germination has been well studied in plants, moss, bacteria, and many fungi (Hohe & Reski, 2005; Huang & Hull, 2017; Vesty et al., 2016). Unfortunately, information on the complex signaling involved in the regulation of germination, particularly in fungi remains lacking. This chapter will discuss germination of fungal spores covering our current understanding of the regulation, signaling, outcomes, and implications of germination of pathogenic fungal spores. Owing to the morphological similarities between the spore-hyphal and yeast-hyphal transition and their relevance for disease progression, relevant aspects of fungal dimorphism will be discussed alongside spore germination in this chapter.
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Affiliation(s)
- Poppy C S Sephton-Clark
- School of Biosciences, Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Kerstin Voelz
- School of Biosciences, Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom.
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43
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Loss O, Bertuzzi M, Yan Y, Fedorova N, McCann BL, Armstrong-James D, Espeso EA, Read ND, Nierman WC, Bignell EM. Mutual independence of alkaline- and calcium-mediated signalling in Aspergillus fumigatus refutes the existence of a conserved druggable signalling nexus. Mol Microbiol 2017; 106:861-875. [PMID: 28922497 PMCID: PMC5725717 DOI: 10.1111/mmi.13840] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2017] [Indexed: 01/03/2023]
Abstract
Functional coupling of calcium‐ and alkaline responsive signalling occurs in multiple fungi to afford efficient cation homeostasis. Host microenvironments exert alkaline stress and potentially toxic concentrations of Ca2+, such that highly conserved regulators of both calcium‐ (Crz) and pH‐ (PacC/Rim101) responsive signalling are crucial for fungal pathogenicity. Drugs targeting calcineurin are potent antifungal agents but also perturb human immunity thereby negating their use as anti‐infectives, abrogation of alkaline signalling has, therefore, been postulated as an adjunctive antifungal strategy. We examined the interdependency of pH‐ and calcium‐mediated signalling in Aspergillus fumigatus and found that calcium chelation severely impedes hyphal growth indicating a critical requirement for this ion independently of ambient pH. Transcriptomic responses to alkaline pH or calcium excess exhibited minimal similarity. Mutants lacking calcineurin, or its client CrzA, displayed normal alkaline tolerance and nuclear translocation of CrzA was unaffected by ambient pH. Expression of a highly conserved, alkaline‐regulated, sodium ATPase was tolerant of genetic or chemical perturbations of calcium‐mediated signalling, but abolished in null mutants of the pH‐responsive transcription factor PacC, and PacC proteolytic processing occurred normally during calcium excess. Taken together our data demonstrate that in A. fumigatus the regulatory hierarchy governing alkaline tolerance circumvents calcineurin signalling.
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Affiliation(s)
- Omar Loss
- Microbiology Section, Centre for Molecular Microbiology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Margherita Bertuzzi
- Manchester Fungal Infection Group, Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester M13 9NT, UK
| | - Yu Yan
- The J. Craig Venter Institute, Infectious Diseases Program, Rockville, MD, USA
| | - Natalie Fedorova
- The J. Craig Venter Institute, Infectious Diseases Program, Rockville, MD, USA
| | - Bethany L McCann
- Manchester Fungal Infection Group, Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester M13 9NT, UK
| | - Darius Armstrong-James
- Fungal Pathogens Laboratory, National Heart and Lung Institute, Imperial College London SW7 2AY, UK
| | - Eduardo A Espeso
- Department of Molecular and Cellular Biology, Centro de Investigaciones Biologicas (C.S.I.C.), Madrid, Spain
| | - Nick D Read
- Manchester Fungal Infection Group, Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester M13 9NT, UK
| | - William C Nierman
- The J. Craig Venter Institute, Infectious Diseases Program, Rockville, MD, USA
| | - Elaine M Bignell
- Manchester Fungal Infection Group, Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester M13 9NT, UK
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44
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Zheng Q, Zhang Q, Bing J, Ding X, Huang G. Environmental and genetic regulation of white-opaque switching inCandida tropicalis. Mol Microbiol 2017; 106:999-1017. [DOI: 10.1111/mmi.13862] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2017] [Indexed: 02/05/2023]
Affiliation(s)
- Qiushi Zheng
- State Key Laboratory of Mycology; Institute of Microbiology, Chinese Academy of Sciences; Beijing 100101 China
- College of life sciences, University of Chinese Academy of Sciences; Beijing 100049 China
| | - Qiuyu Zhang
- State Key Laboratory of Mycology; Institute of Microbiology, Chinese Academy of Sciences; Beijing 100101 China
- College of life sciences, University of Chinese Academy of Sciences; Beijing 100049 China
| | - Jian Bing
- State Key Laboratory of Mycology; Institute of Microbiology, Chinese Academy of Sciences; Beijing 100101 China
| | - Xuefen Ding
- State Key Laboratory of Mycology; Institute of Microbiology, Chinese Academy of Sciences; Beijing 100101 China
| | - Guanghua Huang
- State Key Laboratory of Mycology; Institute of Microbiology, Chinese Academy of Sciences; Beijing 100101 China
- College of life sciences, University of Chinese Academy of Sciences; Beijing 100049 China
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45
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Watcharawipas A, Watanabe D, Takagi H. Enhanced sodium acetate tolerance in Saccharomyces cerevisiae by the Thr255Ala mutation of the ubiquitin ligase Rsp5. FEMS Yeast Res 2017; 17:4587736. [DOI: 10.1093/femsyr/fox083] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 11/01/2017] [Indexed: 12/18/2022] Open
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46
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Jones SE, Elliot MA. Streptomyces Exploration: Competition, Volatile Communication and New Bacterial Behaviours. Trends Microbiol 2017; 25:522-531. [DOI: 10.1016/j.tim.2017.02.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 02/01/2017] [Accepted: 02/03/2017] [Indexed: 10/20/2022]
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47
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Luo Z, Ren H, Mousa JJ, Rangel DEN, Zhang Y, Bruner SD, Keyhani NO. The PacC transcription factor regulates secondary metabolite production and stress response, but has only minor effects on virulence in the insect pathogenic fungus Beauveria bassiana. Environ Microbiol 2017; 19:788-802. [PMID: 28083986 DOI: 10.1111/1462-2920.13648] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 11/15/2016] [Accepted: 12/15/2016] [Indexed: 11/29/2022]
Abstract
The PacC transcription factor is an important component of the fungal ambient pH-responsive regulatory system. Loss of pacC in the insect pathogenic fungus Beauveria bassiana resulted in an alkaline pH-dependent decrease in growth and pH-dependent increased susceptibility to osmotic (salt, sorbitol) stress and SDS. Extreme susceptibility to Congo Red was noted irrespective of pH, and ΔBbpacC conidia showed subtle increases in UV susceptibility. The ΔBbPacC mutant showed a reduced ability to acidify media during growth due to failure to produce oxalic acid. The ΔBbPacC mutant also did not produce the insecticidal compound dipicolinic acid, however, production of a yellow-colored compound was noted. The compound, named bassianolone B, was purified and its structure determined. Despite defects in growth, stress resistance, and oxalate/insecticidal compound production, only a small decrease in virulence was seen for the ΔBbpacC strain in topical insect bioassays using larvae from the greater waxmoth, Galleria mellonella or adults of the beetle, Tenebrio molitor. However, slightly more pronounced decreases were seen in virulence via intrahemcoel injection assays (G. mellonella) and in assays using T. molitor larvae. These data suggest important roles for BbpacC in mediating growth at alkaline pH, regulating secondary metabolite production, and in targeting specific insect stages.
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Affiliation(s)
- Zhibing Luo
- Biotechnology Research Center, Southwest University, Chongqing, 400716, P. R. China.,Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, 32611, USA
| | - Hui Ren
- Biotechnology Research Center, Southwest University, Chongqing, 400716, P. R. China
| | - Jarrod J Mousa
- Department of Chemistry, University of Florida, Gainesville, FL, 32611, USA
| | - Drauzio E N Rangel
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, 746050-50, Brazil
| | - Yongjun Zhang
- Biotechnology Research Center, Southwest University, Chongqing, 400716, P. R. China
| | - Steven D Bruner
- Department of Chemistry, University of Florida, Gainesville, FL, 32611, USA
| | - Nemat O Keyhani
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, 32611, USA.,Genetic Engineering Research Center School of Life Sciences, Chongqing University, Chongqing, 400045, P.R. China
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48
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Martinez-Rossi NM, Peres NTA, Rossi A. Pathogenesis of Dermatophytosis: Sensing the Host Tissue. Mycopathologia 2016; 182:215-227. [DOI: 10.1007/s11046-016-0057-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Accepted: 08/24/2016] [Indexed: 01/09/2023]
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49
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Virgilio S, Cupertino FB, Bernardes NE, Freitas FZ, Takeda AAS, Fontes MRDM, Bertolini MC. Molecular Components of the Neurospora crassa pH Signaling Pathway and Their Regulation by pH and the PAC-3 Transcription Factor. PLoS One 2016; 11:e0161659. [PMID: 27557053 PMCID: PMC4996508 DOI: 10.1371/journal.pone.0161659] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 08/09/2016] [Indexed: 11/19/2022] Open
Abstract
Environmental pH induces a stress response triggering a signaling pathway whose components have been identified and characterized in several fungi. Neurospora crassa shares all six components of the Aspergillus nidulans pH signaling pathway, and we investigate here their regulation during an alkaline pH stress response. We show that the N. crassa pal mutant strains, with the exception of Δpal-9, which is the A. nidulans palI homolog, exhibit low conidiation and are unable to grow at alkaline pH. Moreover, they accumulate the pigment melanin, most likely via regulation of the tyrosinase gene by the pH signaling components. The PAC-3 transcription factor binds to the tyrosinase promoter and negatively regulates its gene expression. PAC-3 also binds to all pal gene promoters, regulating their expression at normal growth pH and/or alkaline pH, which indicates a feedback regulation of PAC-3 in the pal gene expression. In addition, PAC-3 binds to the pac-3 promoter only at alkaline pH, most likely influencing the pac-3 expression at this pH suggesting that the activation of PAC-3 in N. crassa results from proteolytic processing and gene expression regulation by the pH signaling components. In N. crassa, PAC-3 is proteolytically processed in a single cleavage step predominately at alkaline pH; however, low levels of the processed protein can be observed at normal growth pH. We also demonstrate that PAC-3 preferentially localizes in the nucleus at alkaline pH stress and that the translocation may require the N. crassa importin-α since the PAC-3 nuclear localization signal (NLS) has a strong in vitro affinity with importin-α. The data presented here show that the pH signaling pathway in N. crassa shares all the components with the A. nidulans and S. cerevisiae pathways; however, it exhibits some properties not previously described in either organism.
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Affiliation(s)
- Stela Virgilio
- Departamento de Bioquímica e Tecnologia Química, Instituto de Química, Universidade Estadual Paulista, UNESP, 14.800-060, Araraquara, São Paulo, Brazil
| | - Fernanda Barbosa Cupertino
- Departamento de Bioquímica e Tecnologia Química, Instituto de Química, Universidade Estadual Paulista, UNESP, 14.800-060, Araraquara, São Paulo, Brazil
| | - Natália Elisa Bernardes
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista, UNESP, 18.618-970, Botucatu, São Paulo, Brazil
| | - Fernanda Zanolli Freitas
- Departamento de Bioquímica e Tecnologia Química, Instituto de Química, Universidade Estadual Paulista, UNESP, 14.800-060, Araraquara, São Paulo, Brazil
| | - Agnes Alessandra Sekijima Takeda
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista, UNESP, 18.618-970, Botucatu, São Paulo, Brazil
| | - Marcos Roberto de Mattos Fontes
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista, UNESP, 18.618-970, Botucatu, São Paulo, Brazil
| | - Maria Célia Bertolini
- Departamento de Bioquímica e Tecnologia Química, Instituto de Química, Universidade Estadual Paulista, UNESP, 14.800-060, Araraquara, São Paulo, Brazil
- * E-mail:
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50
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Liang W, Guan G, Dai Y, Cao C, Tao L, Du H, Nobile CJ, Zhong J, Huang G. Lactic acid bacteria differentially regulate filamentation in two heritable cell types of the human fungal pathogen Candida albicans. Mol Microbiol 2016; 102:506-519. [PMID: 27479705 DOI: 10.1111/mmi.13475] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/29/2016] [Indexed: 01/17/2023]
Abstract
Microorganisms rarely exist as single species in natural environments. The opportunistic fungal pathogen Candida albicans and lactic acid bacteria (LAB) are common members of the microbiota of several human niches such as the mouth, gut and vagina. Lactic acid bacteria are known to suppress filamentation, a key virulence feature of C. albicans, through the production of lactic acid and other metabolites. Here we report that C. albicans cells switch between two heritable cell types, white and opaque, to undergo filamentation to adapt to diversified environments. We show that acidic pH conditions caused by LAB and low temperatures support opaque cell filamentation, while neutral pH conditions and high temperatures promote white cell filamentation. The cAMP signalling pathway and the Rfg1 transcription factor play major roles in regulating the responses to these conditions. This cell type-specific response of C. albicans to different environmental conditions reflects its elaborate regulatory control of phenotypic plasticity.
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Affiliation(s)
- Weihong Liang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Guobo Guan
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yu Dai
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Chengjun Cao
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Li Tao
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Han Du
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Clarissa J Nobile
- Department of Molecular and Cell Biology, School of Natural Sciences, University of California, Merced, 5200 N. Lake Road, Merced, California, United States of America
| | - Jin Zhong
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Guanghua Huang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
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