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Niu K, Qi YX, Cai HW, Ye YX, Zhou HY, Liu XT, Liu ZQ, Zheng YG. Investigation of the enhancement for Echinocandin B fermentation with methyl oleate from transcription level. Bioprocess Biosyst Eng 2023:10.1007/s00449-023-02883-4. [PMID: 37253987 DOI: 10.1007/s00449-023-02883-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 05/12/2023] [Indexed: 06/01/2023]
Abstract
Echinocandin B (ECB) is the key precursor compound of the antifungal drug Anidulafungin. The effects of the five precursor amino acids on ECB biosynthesis were firstly investigated. It showed that although L-threonine was a main compound of the hexapeptide scaffold of ECB, exogenous addition of L-threonine had no significant effect on the increase of ECB fermentation titer. Meanwhile, the ECB fermentation titer with methyl oleate showed two times higher than that of the other carbon sources. Transcription level analysis of the key genes for ECB biosynthesis indicated that the gene an655543 related to L-threonine biosynthesis showed higher value during the fermentation process, therefore, the exogenous addition of L-threonine had no obvious affection. Furthermore, it indicated that the transcription level of gene ecdA might be the main restriction factor for the ECB biosynthesis. The study provided the research foundation for the modification of the ECB producing strains in the following work.
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Affiliation(s)
- Kun Niu
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Yu-Xin Qi
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Hong-Wei Cai
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Yi-Xin Ye
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Hai-Yan Zhou
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Xiao-Tian Liu
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai, 200235, People's Republic of China
| | - Zhi-Qiang Liu
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China.
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China.
| | - Yu-Guo Zheng
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
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The AbcCl1 transporter of Colletotrichum lindemuthianum acts as a virulence factor involved in fungal detoxification during common bean (Phaseolus vulgaris) infection. Braz J Microbiol 2022; 53:1121-1132. [PMID: 35821347 DOI: 10.1007/s42770-022-00787-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 06/21/2022] [Indexed: 11/02/2022] Open
Abstract
Anthracnose, caused by Colletotrichum lindemuthianum, is a disease affecting the common bean plant, Phaseolus vulgaris. To establish infection, the phytopathogen must survive the toxic compounds (phytoanticipins and phytoalexins) that are produced by the plant as a defense mechanism. To study the detoxification and efflux mechanisms in C. lindemuthianum, the abcCl1 gene, which encodes an ABC transporter, was analyzed. The abcCl1 gene (4558 pb) was predicted to encode a 1450-amino acid protein. Structural analysis of 11 genome sequences from Colletotrichum spp. showed that the number of ABC transporters varied from 34 to 64. AbcCl1 was classified in the ABC-G family of transporters, and it appears to be orthologs to ABC1 from Magnaporthe grisea and FcABC1 from Fusarium culmorum, which are involved in pleiotropic drug resistance. A abcT3 (ΔabcCl1) strain showed reduction on aggressivity when inoculated on bean leaves that presented diminishing anthracnose symptoms, which suggests the important role of AbcCl1 as a virulence factor and in fungal resistance to host compounds. The expression of abcCl1 increased in response to different toxic compounds, such as eugenol, hygromycin, and pisatin phytoalexin. Together, these results suggest that AbcCl1 is involved in fungal resistance to the toxic compounds produced by plants or antagonistic microorganisms.
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Dhandapani K, Sivarajan K, Ravindhiran R, Sekar JN. Fungal Infections as an Uprising Threat to Human Health: Chemosensitization of Fungal Pathogens With AFP From Aspergillus giganteus. Front Cell Infect Microbiol 2022; 12:887971. [PMID: 35694549 PMCID: PMC9174459 DOI: 10.3389/fcimb.2022.887971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 04/19/2022] [Indexed: 11/20/2022] Open
Abstract
Occurrence and intensity of systemic invasive fungal infections have significantly risen in recent decades with large amount of mortality and morbidity rates at global level. Treatment therapy lies on the current antifungal interventions and are often limited due to the emergence of resistance to antifungal agents. Chemosensitization of fungal strains to the conventional antimycotic drugs are of growing concern. Current antifungal drugs often have been reported with poor activity and side effects to the host and have a few number of targets to manifest their efficacy on the pathogens. Indiscriminately, the aforementioned issues have been easily resolved by the development of new intervention strategies. One such approach is to employ combinational therapy that has exhibited a great level of inhibitions than that of a single compound. Chemosensitization of pathogenic mycoses to commercial antifungal drugs could be drastically enhanced by co-application of chemosensitizers along with the conventional drugs. Chemosensitizers could address the resistance mechanisms evolved in the pathogenic fungi and targeting the system to make the organism susceptible to commercially and clinically proven antifungal drugs. However, this strategy has not been overreached to the greater level, but it needs much attention to fight against not only with the pathogen but combat the resistance mechanisms of pathogens to drugs. Natural compounds including plant compounds and microbial proteins act as potential chemosensitizers to break the resistance in mycoses. Aspergillus giganteus, a filamentous fungus, is known to produce a cysteine rich extracellular protein called as antifungal protein (AFP). AFP has shown enhanced efficacy against several filamentous and non-filamentous fungal pathogens. On the basis of the reported studies on its targeted potential against pathogenic mycoses, AFP would be fabricated as a good chemosensitizer to augment the fungicidal efficacy of commercial antimycotic drugs. This paper reviews on breakthrough in the discovery of antifungal drugs along with the resistance patterns of mycoses to commercial drugs followed by the current intervention strategies applied to augment the fungicidal potential of drugs.
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dos Reis TF, Horta MAC, Colabardini AC, Fernandes CM, Silva LP, Bastos RW, Fonseca MVDL, Wang F, Martins C, Rodrigues ML, Silva Pereira C, Del Poeta M, Wong KH, Goldman GH. Screening of Chemical Libraries for New Antifungal Drugs against Aspergillus fumigatus Reveals Sphingolipids Are Involved in the Mechanism of Action of Miltefosine. mBio 2021; 12:e0145821. [PMID: 34372704 PMCID: PMC8406317 DOI: 10.1128/mbio.01458-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 07/06/2021] [Indexed: 12/16/2022] Open
Abstract
Aspergillus fumigatus is an important fungal pathogen and the main etiological agent of aspergillosis, a disease characterized by a noninvasive process that can evolve to a more severe clinical manifestation, called invasive pulmonary aspergillosis (IPA), in immunocompromised patients. The antifungal arsenal to threat aspergillosis is very restricted. Azoles are the main therapeutic approach to control IPA, but the emergence of azole-resistant A. fumigatus isolates has significantly increased over recent decades. Therefore, new strategies are necessary to combat aspergillosis, and drug repurposing has emerged as an efficient and alternative approach for identifying new antifungal drugs. Here, we used a screening approach to analyze A. fumigatus in vitro susceptibility to 1,127 compounds. A. fumigatus was susceptible to 10 compounds, including miltefosine, a drug that displayed fungicidal activity against A. fumigatus. By screening an A. fumigatus transcription factor null library, we identified a single mutant, which has the smiA (sensitive to miltefosine) gene deleted, conferring a phenotype of susceptibility to miltefosine. The transcriptional profiling (RNA-seq) of the wild-type and ΔsmiA strains and chromatin immunoprecipitation coupled to next-generation sequencing (ChIP-Seq) of an SmiA-tagged strain exposed to miltefosine revealed genes of the sphingolipid pathway that are directly or indirectly regulated by SmiA. Sphingolipid analysis demonstrated that the mutant has overall decreased levels of sphingolipids when growing in the presence of miltefosine. The identification of SmiA represents the first genetic element described and characterized that plays a direct role in miltefosine response in fungi. IMPORTANCE The filamentous fungus Aspergillus fumigatus causes a group of diseases named aspergillosis, and their development occurs after the inhalation of conidia dispersed in the environment. Very few classes of antifungal drugs are available for aspergillosis treatment, e.g., azoles, but the emergence of global resistance to azoles in A. fumigatus clinical isolates has increased over recent decades. Repositioning or repurposing drugs already available on the market is an interesting and faster opportunity for the identification of novel antifungal agents. By using a repurposing strategy, we identified 10 different compounds that impact A. fumigatus survival. One of these compounds, miltefosine, demonstrated fungicidal activity against A. fumigatus. The mechanism of action of miltefosine is unknown, and, aiming to get more insights about it, we identified a transcription factor, SmiA (sensitive to miltefosine), important for miltefosine resistance. Our results suggest that miltefosine displays antifungal activity against A. fumigatus, interfering in sphingolipid biosynthesis.
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Affiliation(s)
- Thaila Fernanda dos Reis
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
- MicroControl Innovation Ltd., Ribeirão Preto, São Paulo, Brazil
| | | | - Ana Cristina Colabardini
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Caroline Mota Fernandes
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
| | - Lilian Pereira Silva
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Rafael Wesley Bastos
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | | | - Fang Wang
- Faculty of Health Sciences, University of Macau, Taipa, Macau, SAR, China
| | - Celso Martins
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Oeiras, Portugal
| | - Márcio L. Rodrigues
- Instituto Carlos Chagas (ICC), Fundação Oswaldo Cruz–Fiocruz, Curitiba, Brazil
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Cristina Silva Pereira
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Oeiras, Portugal
| | - Maurizio Del Poeta
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
- Veteran Administration Medical Center, Northport, New York, USA
- MicroRid Technologies Inc., Dix Hills, New York, USA
- Division of Infectious Diseases, School of Medicine, Stony Brook University, New York, USA
| | - Koon Ho Wong
- Faculty of Health Sciences, University of Macau, Taipa, Macau, SAR, China
- Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Avenida da Universidade, Taipa, Macau, SAR, China
- MoE Frontiers Science Center for Precision Oncology, University of Macau, Taipa, Macau, SAR, China
| | - Gustavo H. Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
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Archer M, Xu J. Current Practices for Reference Gene Selection in RT-qPCR of Aspergillus: Outlook and Recommendations for the Future. Genes (Basel) 2021; 12:genes12070960. [PMID: 34202507 PMCID: PMC8307107 DOI: 10.3390/genes12070960] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/20/2021] [Accepted: 06/21/2021] [Indexed: 12/21/2022] Open
Abstract
Aspergillus is a genus of filamentous fungi with vast geographic and ecological distributions. Species within this genus are clinically, agriculturally and biotechnologically relevant, leading to increasing interest in elucidating gene expression dynamics of key metabolic and physiological processes. Reverse-transcription quantitative Polymerase Chain Reaction (RT-qPCR) is a sensitive and specific method of quantifying gene expression. A crucial step for comparing RT-qPCR results between strains and experimental conditions is normalisation to experimentally validated reference gene(s). In this review, we provide a critical analysis of current reference gene selection and validation practices for RT-qPCR gene expression analyses of Aspergillus. Of 90 primary research articles obtained through our PubMed query, 17 experimentally validated the reference gene(s) used. Twenty reference genes were used across the 90 studies, with beta-tubulin being the most used reference gene, followed by actin, 18S rRNA and glyceraldehyde 3-phosphate dehydrogenase. Sixteen of the 90 studies used multiple reference genes for normalisation. Failing to experimentally validate the stability of reference genes can lead to conflicting results, as was the case for four studies. Overall, our review highlights the need to experimentally validate reference genes in RT-qPCR studies of Aspergillus.
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Affiliation(s)
| | - Jianping Xu
- Correspondence: ; Tel.: +1-905-525-9140 (ext. 27934); Fax: +1-905-522-6066
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Son YE, Park HS. Unveiling the Functions of the VosA-VelB Target Gene vidD in Aspergillus nidulans. MYCOBIOLOGY 2021; 49:258-266. [PMID: 34290549 PMCID: PMC8259823 DOI: 10.1080/12298093.2021.1926122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 04/29/2021] [Accepted: 05/03/2021] [Indexed: 06/12/2023]
Abstract
The velvet regulators VosA and VelB are primarily involved in spore maturation and dormancy. Previous studies found that the VosA-VelB hetero-complex coordinates certain target genes that are related to fungal differentiation and conidial maturation in Aspergillus nidulans. Here, we characterized the VosA/VelB-inhibited developmental gene vidD in A. nidulans. Phenotypic analyses demonstrated that the vidD deleted mutant exhibited defect fungal growth, a reduced number of conidia, and delayed formation of sexual fruiting bodies. The deletion of vidD decreased the amount of conidial trehalose, increased the sensitivity against heat stress, and reduced the conidial viability. Moreover, the absence of vidD resulted in increased production of sterigmatocystin. Together, these results show that VidD is required for proper fungal growth, development, and sterigmatocystin production in A. nidulans.
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Affiliation(s)
- Ye-Eun Son
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, Republic of Korea
| | - Hee-Soo Park
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, Republic of Korea
- Department of Integrative Biology, Kyungpook National University, Daegu, Republic of Korea
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Abstract
The fungal zinc finger transcription factor NsdC is named after, and is best known for, its essential role in sexual reproduction (never in sexual development). In previous studies with Aspergillus nidulans, it was also shown to have roles in promotion of vegetative growth and suppression of asexual conidiation. In this study, the function of the nsdC homologue in the opportunistic human pathogen A. fumigatus was investigated. NsdC was again found to be essential for sexual development, with deletion of the nsdC gene in both MAT1-1 and MAT1-2 mating partners of a cross leading to complete loss of fertility. However, a functional copy of nsdC in one mating partner was sufficient to allow sexual reproduction. Deletion of nsdC also led to decreased vegetative growth and allowed conidiation in liquid cultures, again consistent with previous findings. However, NsdC in A. fumigatus was shown to have additional biological functions including response to calcium stress, correct organization of cell wall structure, and response to the cell wall stressors. Furthermore, virulence and host immune recognition were affected. Gene expression studies involving chromatin immunoprecipitation (ChIP) of RNA polymerase II (PolII) coupled to next-generation sequencing (Seq) revealed that deletion of nsdC resulted in changes in expression of over 620 genes under basal growth conditions. This demonstrated that this transcription factor mediates the activity of a wide variety of signaling and metabolic pathways and indicates that despite the naming of the gene, the promotion of sexual reproduction is just one among multiple roles of NsdC.IMPORTANCE Aspergillus fumigatus is an opportunistic human fungal pathogen and the main causal agent of invasive aspergillosis, a life-threatening infection especially in immunocompromised patients. A. fumigatus can undergo both asexual and sexual reproductive cycles, and the regulation of both cycles involves several genes and pathways. Here, we have characterized one of these genetic determinants, the NsdC transcription factor, which was initially identified in a screen of transcription factor null mutants showing sensitivity when exposed to high concentrations of calcium. In addition to its known essential roles in sexual reproduction and control of growth rate and asexual reproduction, we have shown in the present study that A. fumigatus NsdC transcription factor has additional previously unrecognized biological functions including calcium tolerance, cell wall stress response, and correct cell wall organization and functions in virulence and host immune recognition. Our results indicate that NsdC can play novel additional biological functions not directly related to its role played during sexual and asexual processes.
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Westrick NM, Smith DL, Kabbage M. Disarming the Host: Detoxification of Plant Defense Compounds During Fungal Necrotrophy. FRONTIERS IN PLANT SCIENCE 2021; 12:651716. [PMID: 33995447 PMCID: PMC8120277 DOI: 10.3389/fpls.2021.651716] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 03/26/2021] [Indexed: 05/02/2023]
Abstract
While fungal biotrophs are dependent on successfully suppressing/subverting host defenses during their interaction with live cells, necrotrophs, due to their lifestyle are often confronted with a suite of toxic metabolites. These include an assortment of plant defense compounds (PDCs) which can demonstrate broad antifungal activity. These PDCs can be either constitutively present in plant tissue or induced in response to infection, but are nevertheless an important obstacle which needs to be overcome for successful pathogenesis. Fungal necrotrophs have developed a number of strategies to achieve this goal, from the direct detoxification of these compounds through enzymatic catalysis and modification, to the active transport of various PDCs to achieve toxin sequestration and efflux. Studies have shown across multiple pathogens that the efficient detoxification of host PDCs is both critical for successful infection and often a determinant factor in pathogen host range. Here, we provide a broad and comparative overview of the various mechanisms for PDC detoxification which have been identified in both fungal necrotrophs and fungal pathogens which depend on detoxification during a necrotrophic phase of infection. Furthermore, the effect that these mechanisms have on fungal host range, metabolism, and disease control will be discussed.
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Putative Membrane Receptors Contribute to Activation and Efficient Signaling of Mitogen-Activated Protein Kinase Cascades during Adaptation of Aspergillus fumigatus to Different Stressors and Carbon Sources. mSphere 2020; 5:5/5/e00818-20. [PMID: 32938702 PMCID: PMC7494837 DOI: 10.1128/msphere.00818-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The high-osmolarity glycerol (HOG) response pathway is a multifunctional signal transduction pathway that specifically transmits ambient osmotic signals. Saccharomyces cerevisiae Hog1p has two upstream signaling branches, the sensor histidine kinase Sln1p and the receptor Sho1p. The Sho1p branch includes two other proteins, the Msb2p mucin and Opy2p. Aspergillus fumigatus is the leading cause of pulmonary fungal diseases. Here, we investigated the roles played by A. fumigatus SlnASln1p, ShoASho1p, MsbAMsb2p, and OpyAOpy2p putative homologues during the activation of the mitogen-activated protein kinase (MAPK) HOG pathway. The shoA, msbA, and opyA singly and doubly null mutants are important for the cell wall integrity (CWI) pathway, oxidative stress, and virulence as assessed by a Galleria mellonella model. Genetic interactions of ShoA, MsbA, and OpyA are also important for proper activation of the SakAHog1p and MpkASlt2 cascade and the response to osmotic and cell wall stresses. Comparative label-free quantitative proteomics analysis of the singly null mutants with the wild-type strain upon caspofungin exposure indicates that the absence of ShoA, MsbA, and OpyA affects the osmotic stress response, carbohydrate metabolism, and protein degradation. The putative receptor mutants showed altered trehalose and glycogen accumulation, suggesting a role for ShoA, MsbA, and OpyA in sugar storage. Protein kinase A activity was also decreased in these mutants. We also observed genetic interactions between SlnA, ShoA, MsbA, and OpyA, suggesting that both branches are important for activation of the HOG/CWI pathways. Our results help in the understanding of the activation and modulation of the HOG and CWI pathways in this important fungal pathogen.IMPORTANCE Aspergillus fumigatus is an important human-pathogenic fungal species that is responsible for a high incidence of infections in immunocompromised individuals. A. fumigatus high-osmolarity glycerol (HOG) and cell wall integrity pathways are important for the adaptation to different forms of environmental adversity such as osmotic and oxidative stresses, nutrient limitations, high temperatures, and other chemical and mechanical stresses that may be produced by the host immune system and antifungal drugs. Little is known about how these pathways are activated in this fungal pathogen. Here, we characterize four A. fumigatus putative homologues that are important for the activation of the yeast HOG pathway. A. fumigatus SlnASln1p, ShoASho1p, MsbAMsb2p, and OpyAOpy2p are genetically interacting and are essential for the activation of the HOG and cell wall integrity pathways. Our results contribute to the understanding of A. fumigatus adaptation to the host environment.
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Abstract
Aspergillus fumigatus, one of the most important human-pathogenic fungal species, is able to cause aspergillosis, a heterogeneous group of diseases that presents a wide range of clinical manifestations. Invasive pulmonary aspergillosis is the most serious pathology in terms of patient outcome and treatment, with a high mortality rate ranging from 50% to 95% primarily affecting immunocompromised patients. Azoles have been used for many years as the main antifungal agents to treat and prevent invasive aspergillosis. However, there were several reports of evolution of clinical azole resistance in the last decade. Caspofungin, a noncompetitive β-1,3-glucan synthase inhibitor, has been used against A. fumigatus, but it is fungistatic and is recommended as second-line therapy for invasive aspergillosis. More information about caspofungin tolerance and resistance is necessary in order to refine antifungal strategies that target the fungal cell wall. Here, we screened a transcription factor (TF) deletion library for TFs that can mediate caspofungin tolerance and resistance. We have identified 11 TFs that are important for caspofungin sensitivity and/or for the caspofungin paradoxical effect (CPE). These TFs encode proteins involved in the basal modulation of the RNA polymerase II initiation sites, calcium metabolism or cell wall remodeling, and mitochondrial respiratory function. The study of those genes regulated by TFs identified in this work will provide a better understanding of the signaling pathways that are important for caspofungin tolerance and resistance. Aspergillus fumigatus is the leading cause of pulmonary fungal diseases. Azoles have been used for many years as the main antifungal agents to treat and prevent invasive aspergillosis. However, in the last 10 years there have been several reports of azole resistance in A. fumigatus and new strategies are needed to combat invasive aspergillosis. Caspofungin is effective against other human-pathogenic fungal species, but it is fungistatic only against A. fumigatus. Resistance to caspofungin in A. fumigatus has been linked to mutations in the fksA gene that encodes the target enzyme of the drug β-1,3-glucan synthase. However, tolerance of high caspofungin concentrations, a phenomenon known as the caspofungin paradoxical effect (CPE), is also important for subsequent adaptation and drug resistance evolution. Here, we identified and characterized the transcription factors involved in the response to CPE by screening an A. fumigatus library of 484 null transcription factors (TFs) in CPE drug concentrations. We identified 11 TFs that had reduced CPE and that encoded proteins involved in the basal modulation of the RNA polymerase II initiation sites, calcium metabolism, and cell wall remodeling. One of these TFs, FhdA, was important for mitochondrial respiratory function and iron metabolism. The ΔfhdA mutant showed decreased growth when exposed to Congo red or to high temperature. Transcriptome sequencing (RNA-seq) analysis and further experimental validation indicated that the ΔfhdA mutant showed diminished respiratory capacity, probably affecting several pathways related to the caspofungin tolerance and resistance. Our results provide the foundation to understand signaling pathways that are important for caspofungin tolerance and resistance.
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Zhang T, Cao Q, Li N, Liu D, Yuan Y. Transcriptome analysis of fungicide-responsive gene expression profiles in two Penicillium italicum strains with different response to the sterol demethylation inhibitor (DMI) fungicide prochloraz. BMC Genomics 2020; 21:156. [PMID: 32050894 PMCID: PMC7017498 DOI: 10.1186/s12864-020-6564-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 02/07/2020] [Indexed: 12/19/2022] Open
Abstract
Background Penicillium italicum (blue mold) is one of citrus pathogens causing undesirable citrus fruit decay even at strictly-controlled low temperatures (< 10 °C) during shipping and storage. P. italicum isolates with considerably high resistance to sterol demethylation inhibitor (DMI) fungicides have emerged; however, mechanism(s) underlying such DMI-resistance remains unclear. In contrast to available elucidation on anti-DMI mechanism for P. digitatum (green mold), how P. italicum DMI-resistance develops has not yet been clarified. Results The present study prepared RNA-sequencing (RNA-seq) libraries for two P. italicum strains (highly resistant (Pi-R) versus highly sensitive (Pi-S) to DMI fungicides), with and without prochloraz treatment, to identify prochloraz-responsive genes facilitating DMI-resistance. After 6 h prochloraz-treatment, comparative transcriptome profiling showed more differentially expressed genes (DEGs) in Pi-R than Pi-S. Functional enrichments identified 15 DEGs in the prochloraz-induced Pi-R transcriptome, simultaneously up-regulated in P. italicum resistance. These included ATP-binding cassette (ABC) transporter-encoding genes, major facilitator superfamily (MFS) transporter-encoding genes, ergosterol (ERG) anabolism component genes ERG2, ERG6 and EGR11 (CYP51A), mitogen-activated protein kinase (MAPK) signaling-inducer genes Mkk1 and Hog1, and Ca2+/calmodulin-dependent kinase (CaMK) signaling-inducer genes CaMK1 and CaMK2. Fragments Per Kilobase per Million mapped reads (FPKM) analysis of Pi-R transcrtiptome showed that prochloraz induced mRNA increase of additional 4 unigenes, including the other two ERG11 isoforms CYP51B and CYP51C and the remaining kinase-encoding genes (i.e., Bck1 and Slt2) required for Slt2-MAPK signaling. The expression patterns of all the 19 prochloraz-responsive genes, obtained in our RNA-seq data sets, have been validated by quantitative real-time PCR (qRT-PCR). These lines of evidence in together draw a general portrait of anti-DMI mechanisms for P. italicum species. Intriguingly, some strategies adopted by the present Pi-R were not observed in the previously documented prochloraz-resistant P. digitatum transcrtiptomes. These included simultaneous induction of all major EGR11 isoforms (CYP51A/B/C), over-expression of ERG2 and ERG6 to modulate ergosterol anabolism, and concurrent mobilization of Slt2-MAPK and CaMK signaling processes to overcome fungicide-induced stresses. Conclusions The present findings provided transcriptomic evidence on P. italicum DMI-resistance mechanisms and revealed some diversity in anti-DMI strategies between P. italicum and P. digitatum species, contributing to our knowledge on P. italicum DMI-resistance mechanisms.
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Affiliation(s)
- Tingfu Zhang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Qianwen Cao
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Na Li
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China.,Yunnan Higher Education Institutions, College of Life Science and Technology, Honghe University, Mengzi, 661199, China
| | - Deli Liu
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China.
| | - Yongze Yuan
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China.
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de Castro PA, Colabardini AC, Manfiolli AO, Chiaratto J, Silva LP, Mattos EC, Palmisano G, Almeida F, Persinoti GF, Ries LNA, Mellado L, Rocha MC, Bromley M, Silva RN, de Souza GS, Loures FV, Malavazi I, Brown NA, Goldman GH. Aspergillus fumigatus calcium-responsive transcription factors regulate cell wall architecture promoting stress tolerance, virulence and caspofungin resistance. PLoS Genet 2019; 15:e1008551. [PMID: 31887136 PMCID: PMC6948819 DOI: 10.1371/journal.pgen.1008551] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/08/2020] [Accepted: 12/02/2019] [Indexed: 11/28/2022] Open
Abstract
Aspergillus fumigatus causes invasive aspergillosis, the most common life-threatening fungal disease of immuno-compromised humans. The treatment of disseminated infections with antifungal drugs, including echinocandin cell wall biosynthesis inhibitors, is increasingly challenging due to the rise of drug-resistant pathogens. The fungal calcium responsive calcineurin-CrzA pathway influences cell morphology, cell wall composition, virulence, and echinocandin resistance. A screen of 395 A. fumigatus transcription factor mutants identified nine transcription factors important to calcium stress tolerance, including CrzA and ZipD. Here, comparative transcriptomics revealed CrzA and ZipD regulated the expression of shared and unique gene networks, suggesting they participate in both converged and distinct stress response mechanisms. CrzA and ZipD additively promoted calcium stress tolerance. However, ZipD also regulated cell wall organization, osmotic stress tolerance and echinocandin resistance. The absence of ZipD in A. fumigatus caused a significant virulence reduction in immunodeficient and immunocompetent mice. The ΔzipD mutant displayed altered cell wall organization and composition, while being more susceptible to macrophage killing and eliciting an increased pro-inflammatory cytokine response. A higher number of neutrophils, macrophages and activated macrophages were found in ΔzipD infected mice lungs. Collectively, this shows that ZipD-mediated regulation of the fungal cell wall contributes to the evasion of pro-inflammatory responses and tolerance of echinocandin antifungals, and in turn promoting virulence and complicating treatment options.
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Affiliation(s)
- Patrícia Alves de Castro
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Ana Cristina Colabardini
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Adriana Oliveira Manfiolli
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Jéssica Chiaratto
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Lilian Pereira Silva
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Eliciane Cevolani Mattos
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Giuseppe Palmisano
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Fausto Almeida
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Gabriela Felix Persinoti
- Laboratório Nacional de Biorrenováveis (LNBR), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brasil
| | - Laure Nicolas Annick Ries
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Laura Mellado
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Marina Campos Rocha
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Michael Bromley
- Manchester Fungal Infection Group, Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom
| | - Roberto Nascimento Silva
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Gabriel Scalini de Souza
- Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo, São José dos Campos, Brazil
| | - Flávio Vieira Loures
- Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo, São José dos Campos, Brazil
| | - Iran Malavazi
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Neil Andrew Brown
- Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath, United Kingdom
| | - Gustavo H Goldman
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
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GPCR-mediated glucose sensing system regulates light-dependent fungal development and mycotoxin production. PLoS Genet 2019; 15:e1008419. [PMID: 31609971 PMCID: PMC6812930 DOI: 10.1371/journal.pgen.1008419] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 10/24/2019] [Accepted: 09/13/2019] [Indexed: 01/09/2023] Open
Abstract
Microorganisms sense environmental fluctuations in nutrients and light, coordinating their growth and development accordingly. Despite their critical roles in fungi, only a few G-protein coupled receptors (GPCRs) have been characterized. The Aspergillus nidulans genome encodes 86 putative GPCRs. Here, we characterise a carbon starvation-induced GPCR-mediated glucose sensing mechanism in A. nidulans. This includes two class V (gprH and gprI) and one class VII (gprM) GPCRs, which in response to glucose promote cAMP signalling, germination and hyphal growth, while negatively regulating sexual development in a light-dependent manner. We demonstrate that GprH regulates sexual development via influencing VeA activity, a key light-dependent regulator of fungal morphogenesis and secondary metabolism. We show that GprH and GprM are light-independent negative regulators of sterigmatocystin biosynthesis. Additionally, we reveal the epistatic interactions between the three GPCRs in regulating sexual development and sterigmatocystin production. In conclusion, GprH, GprM and GprI constitute a novel carbon starvation-induced glucose sensing mechanism that functions upstream of cAMP-PKA signalling to regulate fungal development and mycotoxin production.
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14
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The Aspergillus fumigatus Mucin MsbA Regulates the Cell Wall Integrity Pathway and Controls Recognition of the Fungus by the Immune System. mSphere 2019; 4:4/3/e00350-19. [PMID: 31217305 PMCID: PMC6584374 DOI: 10.1128/msphere.00350-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Aspergillus fumigatus is a filamentous fungus which causes invasive pulmonary aspergillosis in immunocompromised individuals. In fungi, cell signaling and cell wall plasticity are crucial for maintaining physiologic processes. In this context, Msb2 is an important signaling mucin responsible for activation of a variety of mitogen-activated protein kinase (MAPK)-dependent signaling pathways that regulate cell growth in several organisms, such as the cell wall integrity (CWI) pathway. Here, we aimed to characterize the MSB2 homologue in A. fumigatus Our results showed that MsbA plays a role in the vegetative and reproductive development of the fungus, in stress adaptation, and in resistance to antifungal drugs by modulating the CWI pathway gene expression. Importantly, cell wall composition is also responsible for activation of diverse receptors of the host immune system, thus leading to a proper immune response. In a model of acute Aspergillus pulmonary infection, results demonstrate that the ΔmsbA mutant strain induced less inflammation with diminished cell influx into the lungs and lower cytokine production, culminating in increased lethality rate. These results characterize for the first time the role of the signaling mucin MsbA in the pathogen A. fumigatus, as a core sensor for cell wall morphogenesis and an important regulator of virulence.IMPORTANCE Aspergillus fumigatus is an opportunistic fungus with great medical importance. During infection, Aspergillus grows, forming hyphae that colonize the lung tissue and invade and spread over the mammal host, resulting in high mortality rates. The knowledge of the mechanisms responsible for regulation of fungal growth and virulence comprises an important point to better understand fungal physiology and host-pathogen interactions. Msb2 is a mucin that acts as a sensor and an upstream regulator of the MAPK pathway responsible for fungal development in Candida albicans and Aspergillus nidulans Here, we show the role of the signaling mucin MsbA in the pathogen A. fumigatus, as a core sensor for cell wall morphogenesis, fungal growth, and virulence. Moreover, we show that cell wall composition, controlled by MsbA, is detrimental for fungal recognition and clearance by immune cells. Our findings are important for the understanding of how fungal sensors modulate cell physiology.
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15
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de Gouvêa PF, Gerolamo LE, Bernardi AV, Pereira LMS, Uyemura SA, Dinamarco TM. Lytic Polysaccharide Monooxygenase from Aspergillus fumigatus can Improve Enzymatic Cocktail Activity During Sugarcane Bagasse Hydrolysis. Protein Pept Lett 2019; 26:377-385. [DOI: 10.2174/0929866526666190228163629] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 02/13/2019] [Accepted: 02/13/2019] [Indexed: 12/12/2022]
Abstract
Background:
Lytic Polysaccharide Monooxygenases (LPMOs) are auxiliary accessory
enzymes that act synergistically with cellulases and which are increasingly being used in secondgeneration
bioethanol production from biomasses. Several LPMOs have been identified in various
filamentous fungi, including Aspergillus fumigatus. However, many LPMOs have not been characterized
yet.
Objective:
To report the role of uncharacterized A. fumigatus AfAA9_B LPMO.
Methods:
qRT-PCR analysis was employed to analyze the LPMO gene expression profile in different
carbon sources. The gene encoding an AfAA9_B (Afu4g07850) was cloned into the vector pET-
28a(+), expressed in the E. coli strain RosettaTM (DE3) pLysS, and purified by a Ni2+-nitrilotriacetic
(Ni-NTA) agarose resin. To evaluate the specific LPMO activity, the purified protein peroxidase
activity was assessed. The auxiliary LPMO activity was investigated by the synergistic activity in
Celluclast 1.5L enzymatic cocktail.
Results:
LPMO was highly induced in complex biomass like sugarcane bagasse (SEB), Avicel®
PH-101, and CM-cellulose. The LPMO gene encoded a protein comprising 250 amino acids, without
a CBM domain. After protein purification, the AfAA9_B molecular mass estimated by SDSPAGE
was 35 kDa. The purified protein specific peroxidase activity was 8.33 ± 1.9 U g-1. Upon
addition to Celluclast 1.5L, Avicel® PH-101 and SEB hydrolysis increased by 18% and 22%, respectively.
Conclusion:
A. fumigatus LPMO is a promising candidate to enhance the currently available enzymatic
cocktail and can therefore be used in second-generation ethanol production.
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Affiliation(s)
- Paula Fagundes de Gouvêa
- Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - Luis Eduardo Gerolamo
- Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - Aline Vianna Bernardi
- Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - Lucas Matheus Soares Pereira
- Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - Sergio Akira Uyemura
- Faculdade de Ciencias Farmaceuticas de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - Taisa Magnani Dinamarco
- Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
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16
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Bermúdez-García E, Peña-Montes C, Martins I, Pais J, Pereira CS, Sánchez S, Farrés A. Regulation of the cutinases expressed by Aspergillus nidulans and evaluation of their role in cutin degradation. Appl Microbiol Biotechnol 2019; 103:3863-3874. [DOI: 10.1007/s00253-019-09712-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 02/17/2019] [Accepted: 02/23/2019] [Indexed: 11/29/2022]
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17
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Song HY, Choi D, Han DM, Kim DH, Kim JM. A Novel Rapid Fungal Promoter Analysis System Using the Phosphopantetheinyl Transferase Gene, npgA, in Aspergillus nidulans. MYCOBIOLOGY 2018; 46:429-439. [PMID: 30637152 PMCID: PMC6319467 DOI: 10.1080/12298093.2018.1548806] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 11/04/2018] [Accepted: 11/05/2018] [Indexed: 06/09/2023]
Abstract
To develop a convenient promoter analysis system for fungi, a null-pigment mutant (NPG) of Aspergillus nidulans was used with the 4'-phosphopantetheinyl transferase (PPTase) gene, npgA, which restores the normal pigmentation in A. nidulans, as a new reporter gene. The functional organization of serially deleted promoter regions of the A. nidulans trpC gene and the Cryphonectria parasitica crp gene in filamentous fungi was representatively investigated to establish a novel fungal promoter assay system that depends on color complementation of the NPG mutant with the PPTase npgA gene. Several promoter regions of the trpC and crp genes were fused to the npgA gene containing the 1,034-bp open reading frame and the 966-bp 3' downstream region from the TAA, and the constructed fusions were introduced into the NPG mutant in A. nidulans to evaluate color recovery due to the transcriptional activity of the sequence elements. Serial deletion of the trpC and crp promoter regions in this PPTase reporter assay system reaffirmed results in previous reports by using the fungal transformation step without a laborious verification process. This approach suggests a more rapid and convenient system than conventional analyses for fungal gene expression studies.
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Affiliation(s)
- Ha-Yeon Song
- Department of Bio-Environmental Chemistry, Institute of Life Science and Natural Resources, Wonkwang University, Iksan, Chonbuk, Korea
| | - Dahye Choi
- Department of Bio-Environmental Chemistry, Institute of Life Science and Natural Resources, Wonkwang University, Iksan, Chonbuk, Korea
| | - Dong-Min Han
- Division of Biological Sciences, Wonkwang University, Iksan, Chonbuk, Korea
| | - Dae-Hyuk Kim
- Department of Molecular Biology and Department of Bioactive Material Science, Institute for Molecular Biology and Genetics, Chonbuk National University, Jeonju, Chonbuk, Korea
| | - Jung-Mi Kim
- Department of Bio-Environmental Chemistry, Institute of Life Science and Natural Resources, Wonkwang University, Iksan, Chonbuk, Korea
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Functional characterization of GH7 endo-1,4-β-glucanase from Aspergillus fumigatus and its potential industrial application. Protein Expr Purif 2018; 150:1-11. [DOI: 10.1016/j.pep.2018.04.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 04/24/2018] [Accepted: 04/24/2018] [Indexed: 11/23/2022]
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de Gouvêa PF, Bernardi AV, Gerolamo LE, de Souza Santos E, Riaño-Pachón DM, Uyemura SA, Dinamarco TM. Transcriptome and secretome analysis of Aspergillus fumigatus in the presence of sugarcane bagasse. BMC Genomics 2018; 19:232. [PMID: 29614953 PMCID: PMC5883313 DOI: 10.1186/s12864-018-4627-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 03/27/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Sugarcane bagasse has been proposed as a lignocellulosic residue for second-generation ethanol (2G) produced by breaking down biomass into fermentable sugars. The enzymatic cocktails for biomass degradation are mostly produced by fungi, but low cost and high efficiency can consolidate 2G technologies. A. fumigatus plays an important role in plant biomass degradation capabilities and recycling. To gain more insight into the divergence in gene expression during steam-exploded bagasse (SEB) breakdown, this study profiled the transcriptome of A. fumigatus by RNA sequencing to compare transcriptional profiles of A. fumigatus grown on media containing SEB or fructose as the sole carbon source. Secretome analysis was also performed using SDS-PAGE and LC-MS/MS. RESULTS The maximum activities of cellulases (0.032 U mL-1), endo-1,4-β--xylanase (10.82 U mL-1) and endo-1,3-β glucanases (0.77 U mL-1) showed that functional CAZymes (carbohydrate-active enzymes) were secreted in the SEB culture conditions. Correlations between transcriptome and secretome data identified several CAZymes in A. fumigatus. Particular attention was given to CAZymes related to lignocellulose degradation and sugar transporters. Genes encoding glycoside hydrolase classes commonly expressed during the breakdown of cellulose, such as GH-5, 6, 7, 43, 45, and hemicellulose, such as GH-2, 10, 11, 30, 43, were found to be highly expressed in SEB conditions. Lytic polysaccharide monooxygenases (LPMO) classified as auxiliary activity families AA9 (GH61), CE (1, 4, 8, 15, 16), PL (1, 3, 4, 20) and GT (1, 2, 4, 8, 20, 35, 48) were also differentially expressed in this condition. Similarly, the most important enzymes related to biomass degradation, including endoxylanases, xyloglucanases, β-xylosidases, LPMOs, α-arabinofuranosidases, cellobiohydrolases, endoglucanases and β-glucosidases, were also identified in the secretome. CONCLUSIONS This is the first report of a transcriptome and secretome experiment of Aspergillus fumigatus in the degradation of pretreated sugarcane bagasse. The results suggest that this strain employs important strategies for this complex degradation process. It was possible to identify a set of genes and proteins that might be applied in several biotechnology fields. This knowledge can be exploited for the improvement of 2G ethanol production by the rational design of enzymatic cocktails.
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Affiliation(s)
- Paula Fagundes de Gouvêa
- Faculty of Philosophy, Sciences and Literature of Ribeirão Preto, Chemistry Department, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Aline Vianna Bernardi
- Faculty of Philosophy, Sciences and Literature of Ribeirão Preto, Chemistry Department, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Luis Eduardo Gerolamo
- Faculty of Philosophy, Sciences and Literature of Ribeirão Preto, Chemistry Department, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Emerson de Souza Santos
- Faculty of Pharmaceutical Science, Department of Clinical, Toxicological and Bromatological Analysis, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Diego Mauricio Riaño-Pachón
- Brazilian Bioethanol Science and Technology Laboratory, Campinas, São Paulo, Brazil
- Current address: Laboratory of Regulatory Systems Biology, Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Sergio Akira Uyemura
- Faculty of Pharmaceutical Science, Department of Clinical, Toxicological and Bromatological Analysis, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Taisa Magnani Dinamarco
- Faculty of Philosophy, Sciences and Literature of Ribeirão Preto, Chemistry Department, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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20
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Investigation of Multiple Resistance Mechanisms in Voriconazole-Resistant Aspergillus flavus Clinical Isolates from a Chest Hospital Surveillance in Delhi, India. Antimicrob Agents Chemother 2018; 62:AAC.01928-17. [PMID: 29311090 DOI: 10.1128/aac.01928-17] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 12/30/2017] [Indexed: 11/20/2022] Open
Abstract
Invasive and allergic infections by Aspergillus flavus are more common in tropical and subtropical countries. The emergence of voriconazole (VRC) resistance in A. flavus impacts the management of aspergillosis, as azoles are used as the first-line and empirical therapy. We screened 120 molecularly confirmed A. flavus isolates obtained from respiratory and sinonasal specimens in a chest hospital in Delhi, India, for azole resistance using the CLSI broth microdilution (CLSI-BMD) method. Overall, 2.5% (n = 3/120) of A. flavus isolates had VRC MICs above epidemiological cutoff values (>1 μg/ml). The whole-genome sequence analysis of three non-wild-type (WT) A. flavus isolates with high VRC MICs showed polymorphisms in azole target genes (cyp51A, cyp51B, and cyp51C). Further, four novel substitutions (S196F, A324P, N423D, and V465M) encoded in the cyp51C gene were found in a single non-WT isolate which also exhibited overexpression of cyp51 (cyp51A, -B, and -C) genes and transporter genes, namely, MDR1, MDR2, atrF, and mfs1 The homology model of the non-WT isolate suggests that substitutions S196F and N423D exhibited major structural and functional effects on cyp51C drug binding. The substrate (drug) may not be able to bind to binding pocket due to changes in the pocket size or closing down or narrowing of cavities in drug entry channels. Notably, the remaining two VRC-resistant A. flavus isolates, including the one which had a pan-azole resistance phenotype (itraconazole and posaconazole), did not show upregulation of any of the analyzed target genes. These results suggest that multiple target genes and mechanisms could simultaneously contribute to azole resistance in A. flavus.
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21
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Sharma C, Chowdhary A. Molecular bases of antifungal resistance in filamentous fungi. Int J Antimicrob Agents 2017; 50:607-616. [DOI: 10.1016/j.ijantimicag.2017.06.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Revised: 06/16/2017] [Accepted: 06/24/2017] [Indexed: 01/15/2023]
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22
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Manfiolli AO, de Castro PA, dos Reis TF, Dolan S, Doyle S, Jones G, Riaño Pachón DM, Ulaş M, Noble LM, Mattern DJ, Brakhage AA, Valiante V, Silva-Rocha R, Bayram O, Goldman GH. Aspergillus fumigatusprotein phosphatase PpzA is involved in iron assimilation, secondary metabolite production, and virulence. Cell Microbiol 2017; 19. [DOI: 10.1111/cmi.12770] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 06/28/2017] [Accepted: 07/14/2017] [Indexed: 01/19/2023]
Affiliation(s)
| | - Patrícia Alves de Castro
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto; Universidade de São Paulo; Ribeirão Preto Brazil
| | - Thaila Fernanda dos Reis
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto; Universidade de São Paulo; Ribeirão Preto Brazil
| | - Stephen Dolan
- Department of Biology; Maynooth University; Maynooth Co. Kildare Ireland
| | - Sean Doyle
- Department of Biology; Maynooth University; Maynooth Co. Kildare Ireland
| | - Gary Jones
- Department of Biology; Maynooth University; Maynooth Co. Kildare Ireland
| | - Diego M. Riaño Pachón
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE); Centro Nacional de Pesquisa em Energia e Materiais (CNPEM); Campinas São Paulo Brazil
| | - Mevlüt Ulaş
- Department of Biology; Maynooth University; Maynooth Co. Kildare Ireland
| | | | - Derek J. Mattern
- Department of Molecular and Applied Microbiology; Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute; Jena Germany
- University of Jena; Jena Germany
| | - Axel A. Brakhage
- Department of Molecular and Applied Microbiology; Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute; Jena Germany
- University of Jena; Jena Germany
| | - Vito Valiante
- Leibniz Research Group-Biobricks of Microbial Natural Product Syntheses; Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute; Jena Germany
| | - Rafael Silva-Rocha
- Faculdade de Medicina de Ribeirão Preto; Universidade de São Paulo; Ribeirão Preto Brazil
| | - Ozgur Bayram
- Department of Biology; Maynooth University; Maynooth Co. Kildare Ireland
| | - Gustavo H. Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto; Universidade de São Paulo; Ribeirão Preto Brazil
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Genetics, Molecular, and Proteomics Advances in Filamentous Fungi. Curr Microbiol 2017; 74:1226-1236. [PMID: 28733909 DOI: 10.1007/s00284-017-1308-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 07/13/2017] [Indexed: 10/19/2022]
Abstract
Filamentous fungi play a dynamic role in health and the environment. In addition, their unique and complex hyphal structures are involved in their morphogenesis, integrity, synthesis, and degradation, according to environmental and physiological conditions and resource availability. However, in biotechnology, it has a great value in the production of enzymes, pharmaceuticals, and food ingredients. The beginning of nomenclature of overall fungi started in early 1990 after which the categorization, interior and exterior mechanism, function, molecular and genetics study took pace. This mini-review has emphasized some of the important aspects of filamentous fungi, their pattern of life cycle, history, and development of different strategic methods applied to exploit this unique organism. New trends and concepts that have been applied to overcome obstacle because of their basic structure related to genomics and systems biology has been presented. Furthermore, the future aspects and challenges that need to be deciphered to get a bigger and better picture of filamentous fungi have been discussed.
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The low affinity glucose transporter HxtB is also involved in glucose signalling and metabolism in Aspergillus nidulans. Sci Rep 2017; 7:45073. [PMID: 28361917 PMCID: PMC5374493 DOI: 10.1038/srep45073] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 02/17/2017] [Indexed: 02/06/2023] Open
Abstract
One of the drawbacks during second-generation biofuel production from plant lignocellulosic biomass is the accumulation of glucose, the preferred carbon source of microorganisms, which causes the repression of hydrolytic enzyme secretion by industrially relevant filamentous fungi. Glucose sensing, subsequent transport and cellular signalling pathways have been barely elucidated in these organisms. This study therefore characterized the transcriptional response of the filamentous fungus Aspergillus nidulans to the presence of high and low glucose concentrations under continuous chemostat cultivation with the aim to identify novel factors involved in glucose sensing and signalling. Several transcription factor- and transporter-encoding genes were identified as being differentially regulated, including the previously characterized glucose and xylose transporter HxtB. HxtB was confirmed to be a low affinity glucose transporter, localizing to the plasma membrane under low- and high-glucose conditions. Furthermore, HxtB was shown to be involved in conidiation-related processes and may play a role in downstream glucose signalling. A gene predicted to encode the protein kinase PskA was also identified as being important for glucose metabolism. This study identified several proteins with predicted roles in glucose metabolic processes and provides a foundation for further investigation into the response of biotechnologically important filamentous fungi to glucose.
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Canela HMS, Takami LA, da Silva Ferreira ME. cipC is important for Aspergillus fumigatus virulence. APMIS 2017; 125:141-147. [PMID: 28120495 DOI: 10.1111/apm.12648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 11/11/2016] [Indexed: 11/28/2022]
Abstract
Aspergillus fumigatus is the main causative agent of invasive aspergillosis, a disease that affects immunocompromised patients and has a high mortality rate. We previously observed that the transcription of a cipC-like gene was increased when A. fumigatus encountered an increased CO2 concentration, as occurs during the infection process. CipC is a protein of unknown function that might be associated with fungal pathogenicity. In this study, the cipC gene was disrupted in A. fumigatus to evaluate its importance for fungal pathogenicity. The gene was replaced, and the germination, growth phenotype, stress responses, and virulence of the resultant mutant were assessed. Although cipC was not essential, its deletion attenuated A. fumigatus virulence in a low-dose murine infection model, suggesting the involvement of the cipC gene in the virulence of this fungus. This study is the first to disrupt the cipC gene in A. fumigatus.
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Affiliation(s)
| | - Luciano Akira Takami
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
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26
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Sharma Ghimire P, Ouyang H, Wang Q, Luo Y, Shi B, Yang J, Lü Y, Jin C. Insight into Enzymatic Degradation of Corn, Wheat, and Soybean Cell Wall Cellulose Using Quantitative Secretome Analysis of Aspergillus fumigatus. J Proteome Res 2016; 15:4387-4402. [PMID: 27618962 DOI: 10.1021/acs.jproteome.6b00465] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lignocelluloses contained in animal forage cannot be digested by pigs or poultry with 100% efficiency. On contrary, Aspergillus fumigatus, a saprophytic filamentous fungus, is known to harbor 263 glycoside hydrolase encoding genes, suggesting that A. fumigatus is an efficient lignocellulose degrader. Hence the present study uses corn, wheat, or soybean as a sole carbon source to culture A. fumigatus under animal physiological condition to understand how cellulolytic enzymes work together to achieve an efficient degradation of lignocellulose. Our results showed that A. fumigatus produced different sets of enzymes to degrade lignocelluloses derived from corn, wheat, or soybean cell wall. In addition, the cellulolytic enzymes produced by A. fumigatus were stable under acidic condition or at higher temperatures. Using isobaric tags for a relative and absolute quantification (iTRAQ) approach, a total of ∼600 extracellular proteins were identified and quantified, in which ∼50 proteins were involved in lignocellulolysis, including cellulases, hemicellulases, lignin-degrading enzymes, and some hypothetical proteins. Data are available via ProteomeXchange with identifier PXD004670. On the basis of quantitative iTRAQ results, 14 genes were selected for further confirmation by RT-PCR. Taken together, our results indicated that the expression and regulation of lignocellulolytic proteins in the secretome of A. fumigatus were dependent on both nature and complexity of cellulose, thus suggesting that a different enzyme system is required for degradation of different lignocelluloses derived from plant cells. Although A. fumigatus is a pathogenic fungus and cannot be directly used as an enzyme source, as an efficient lignocellulose degrader its strategy to synergistically degrade various lignocelluloses with different enzymes can be used to design enzyme combination for optimal digestion and absorption of corn, wheat, or soybean that are used as forage of pig and poultry.
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Affiliation(s)
- Prakriti Sharma Ghimire
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences , Beijing 100101, China
- University of Chinese Academy of Sciences , Beijing 100101, China
- Himalayan Environment Research Institute (HERI) , Bouddha-6, Kathmandu, Nepal
| | - Haomiao Ouyang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences , Beijing 100101, China
| | - Qian Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences , Beijing 100101, China
| | - Yuanming Luo
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences , Beijing 100101, China
| | - Bo Shi
- Feed Research Institute, Chinese Academy of Agricultural Sciences , Beijing 100081, China
| | - Jinghua Yang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences , Beijing 100101, China
| | - Yang Lü
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences , Beijing 100101, China
| | - Cheng Jin
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences , Beijing 100101, China
- University of Chinese Academy of Sciences , Beijing 100101, China
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The CreB deubiquitinating enzyme does not directly target the CreA repressor protein in Aspergillus nidulans. Curr Genet 2016; 63:647-667. [DOI: 10.1007/s00294-016-0666-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/23/2016] [Accepted: 08/24/2016] [Indexed: 12/12/2022]
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28
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Alves de Castro P, dos Reis TF, Dolan SK, Manfiolli AO, Brown NA, Jones GW, Doyle S, Riaño-Pachón DM, Squina FM, Caldana C, Singh A, Del Poeta M, Hagiwara D, Silva-Rocha R, Goldman GH. The Aspergillus fumigatus SchA SCH9 kinase modulates SakA HOG1 MAP kinase activity and it is essential for virulence. Mol Microbiol 2016; 102:642-671. [PMID: 27538790 PMCID: PMC5207228 DOI: 10.1111/mmi.13484] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2016] [Indexed: 02/06/2023]
Abstract
The serine-threonine kinase TOR, the Target of Rapamycin, is an important regulator of nutrient, energy and stress signaling in eukaryotes. Sch9, a Ser/Thr kinase of AGC family (the cAMP-dependent PKA, cGMP- dependent protein kinase G and phospholipid-dependent protein kinase C family), is a substrate of TOR. Here, we characterized the fungal opportunistic pathogen Aspergillus fumigatus Sch9 homologue (SchA). The schA null mutant was sensitive to rapamycin, high concentrations of calcium, hyperosmotic stress and SchA was involved in iron metabolism. The ΔschA null mutant showed increased phosphorylation of SakA, the A. fumigatus Hog1 homologue. The schA null mutant has increased and decreased trehalose and glycerol accumulation, respectively, suggesting SchA performs different roles for glycerol and trehalose accumulation during osmotic stress. The schA was transcriptionally regulated by osmotic stress and this response was dependent on SakA and MpkC. The double ΔschA ΔsakA and ΔschA ΔmpkC mutants were more sensitive to osmotic stress than the corresponding parental strains. Transcriptomics and proteomics identified direct and indirect targets of SchA post-exposure to hyperosmotic stress. Finally, ΔschA was avirulent in a low dose murine infection model. Our results suggest there is a complex network of interactions amongst the A. fumigatus TOR, SakA and SchA pathways.
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Affiliation(s)
- Patrícia Alves de Castro
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Thaila Fernanda dos Reis
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Stephen K. Dolan
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - Adriana Oliveira Manfiolli
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Neil Andrew Brown
- Plant Biology and Crop Science, Rothamsted Research, Harpenden, Herts AL5 2JQ, UK
| | - Gary W. Jones
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - Sean Doyle
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - Diego M. Riaño-Pachón
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, Campinas, São Paulo, CEP 13083-970, Brasil
| | - Fábio Márcio Squina
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, Campinas, São Paulo, CEP 13083-970, Brasil
| | - Camila Caldana
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, Campinas, São Paulo, CEP 13083-970, Brasil
- Max Planck Partner Group at Brazilian Bioethanol Science and Technology Laboratory, Brazilian Center for Research in Energy and Materials, São Paulo, Brazil
| | - Ashutosh Singh
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, USA
| | - Maurizio Del Poeta
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, USA
| | - Daisuke Hagiwara
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Rafael Silva-Rocha
- Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Gustavo H. Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
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29
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Pereira Silva L, Alves de Castro P, Dos Reis TF, Paziani MH, Von Zeska Kress MR, Riaño-Pachón DM, Hagiwara D, Ries LNA, Brown NA, Goldman GH. Genome-wide transcriptome analysis of Aspergillus fumigatus exposed to osmotic stress reveals regulators of osmotic and cell wall stresses that are SakA HOG1 and MpkC dependent. Cell Microbiol 2016; 19. [PMID: 27706915 DOI: 10.1111/cmi.12681] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 09/19/2016] [Accepted: 10/04/2016] [Indexed: 12/24/2022]
Abstract
Invasive aspergillosis is predominantly caused by Aspergillus fumigatus, and adaptations to stresses experienced within the human host are a prerequisite for the survival and virulence strategies of the pathogen. The central signal transduction pathway operating during hyperosmotic stress is the high osmolarity glycerol mitogen-activated protein kinase cascade. A. fumigatus MpkC and SakA, orthologues of the Saccharomyces cerevisiae Hog1p, constitute the primary regulator of the hyperosmotic stress response. We compared A. fumigatus wild-type transcriptional response to osmotic stress with the ΔmpkC, ΔsakA, and ΔmpkC ΔsakA strains. Our results strongly indicate that MpkC and SakA have independent and collaborative functions during the transcriptional response to transient osmotic stress. We have identified and characterized null mutants for four A. fumigatus basic leucine zipper proteins transcription factors. The atfA and atfB have comparable expression levels with the wild-type in ΔmpkC but are repressed in ΔsakA and ΔmpkC ΔsakA post-osmotic stress. The atfC and atfD have reduced expression levels in all mutants post-osmotic stress. The atfA-D null mutants displayed several phenotypes related to osmotic, oxidative, and cell wall stresses. The ΔatfA and ΔatfB were shown to be avirulent and to have attenuated virulence, respectively, in both Galleria mellonella and a neutropenic murine model of invasive pulmonary aspergillosis.
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Affiliation(s)
- Lilian Pereira Silva
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Patrícia Alves de Castro
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Thaila Fernanda Dos Reis
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Mario Henrique Paziani
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | | | - Diego M Riaño-Pachón
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), São Paulo, Brazil
| | - Daisuke Hagiwara
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Laure N A Ries
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Neil Andrew Brown
- Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire, UK
| | - Gustavo H Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
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30
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de Castro PA, Chiaratto J, Morais ER, Dos Reis TF, Mitchell TK, Brown NA, Goldman GH. The putative flavin carrier family FlcA-C is important for Aspergillus fumigatus virulence. Virulence 2016; 8:797-809. [PMID: 27652896 DOI: 10.1080/21505594.2016.1239010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Aspergillus fumigatus is an opportunistic fungal pathogen and the most important species causing pulmonary fungal infections. The signaling by calcium is very important for A. fumigatus pathogenicity and it is regulated by the transcription factor CrzA. We have previously used used ChIP-seq (Chromatin Immunoprecipitation DNA sequencing) aiming to identify gene targets regulated by CrzA. We have identified among several genes regulated by calcium stress, the putative flavin transporter, flcA. This transporter belongs to a small protein family composed of FlcA, B, and C. The ΔflcA null mutant showed several phenotypes, such as morphological defects, increased sensitivity to calcium chelating-agent ethylene glycol tetraacetic acid (EGTA), cell wall or oxidative damaging agents and metals, repre-sentative of deficiencies in calcium signaling and iron homeostasis. Increasing calcium concentrations improved significantly the ΔflcA growth and conidiation, indicating that ΔflcA mutant has calcium insufficiency. Finally, ΔflcA-C mutants showed reduced flavin adenine dinucleotide (FAD) and were avirulent in a low dose murine infection model.
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Affiliation(s)
- Patrícia A de Castro
- a Faculdade de Ciências Farmacêuticas de Ribeirão Preto and Faculdade de Medicina de Ribeirão Preto , Universidade de São Paulo , Ribeirão Preto , Brazil
| | - Jéssica Chiaratto
- a Faculdade de Ciências Farmacêuticas de Ribeirão Preto and Faculdade de Medicina de Ribeirão Preto , Universidade de São Paulo , Ribeirão Preto , Brazil
| | - Enyara Rezende Morais
- a Faculdade de Ciências Farmacêuticas de Ribeirão Preto and Faculdade de Medicina de Ribeirão Preto , Universidade de São Paulo , Ribeirão Preto , Brazil
| | - Thaila Fernanda Dos Reis
- a Faculdade de Ciências Farmacêuticas de Ribeirão Preto and Faculdade de Medicina de Ribeirão Preto , Universidade de São Paulo , Ribeirão Preto , Brazil
| | - Thomas K Mitchell
- b Department of Plant Pathology , The Ohio State University , Columbus , OH , USA
| | - Neil A Brown
- c Plant Biology and Crop Science, Rothamsted Research , Harpenden, Herts , UK
| | - Gustavo H Goldman
- a Faculdade de Ciências Farmacêuticas de Ribeirão Preto and Faculdade de Medicina de Ribeirão Preto , Universidade de São Paulo , Ribeirão Preto , Brazil
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Alam MA, Kamlangdee N, Kelly JM. The CreB deubiquitinating enzyme does not directly target the CreA repressor protein in Aspergillus nidulans. Curr Genet 2016:10.1007/s00294-016-0643-x. [PMID: 27589970 DOI: 10.1007/s00294-016-0643-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/23/2016] [Accepted: 08/24/2016] [Indexed: 11/25/2022]
Abstract
Ubiquitination/deubiquitination pathways are now recognized as key components of gene regulatory mechanisms in eukaryotes. The major transcriptional repressor for carbon catabolite repression in Aspergillus nidulans is CreA, and mutational analysis led to the suggestion that a regulatory ubiquitination/deubiquitination pathway is involved. A key unanswered question is if and how this pathway, comprising CreB (deubiquitinating enzyme) and HulA (ubiquitin ligase) and other proteins, is involved in the regulatory mechanism. Previously, missense alleles of creA and creB were analysed for genetic interactions, and here we extended this to complete loss-of-function alleles of creA and creB, and compared morphological and biochemical phenotypes, which confirmed genetic interaction between the genes. We investigated whether CreA, or a protein in a complex with it, is a direct target of the CreB deubiquitination enzyme, using co-purifications of CreA and CreB, first using strains that overexpress the proteins and then using strains that express the proteins from their native promoters. The Phos-tag system was used to show that CreA is a phosphorylated protein, but no ubiquitination was detected using anti-ubiquitin antibodies and Western analysis. These findings were confirmed using mass spectrometry, which confirmed that CreA was differentially phosphorylated but not ubiquitinated. Thus, CreA is not a direct target of CreB, and nor are proteins that form part of a stable complex with CreA a target of CreB. These results open up new questions regarding the molecular mechanism of CreA repressing activity, and how the ubiquitination pathway involving CreB interacts with this regulatory network.
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Affiliation(s)
- Md Ashiqul Alam
- Department of Genetics and Evolution, The University of Adelaide, Adelaide, 5005, Australia
| | - Niyom Kamlangdee
- Department of Genetics and Evolution, The University of Adelaide, Adelaide, 5005, Australia
- Walailak University, 222 Thaiburi Thasala, Nakhonsithamrat, Nakhon Si Thammarat, 80160, Thailand
| | - Joan M Kelly
- Department of Genetics and Evolution, The University of Adelaide, Adelaide, 5005, Australia.
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Brown NA, Ries LNA, Reis TF, Rajendran R, Corrêa dos Santos RA, Ramage G, Riaño-Pachón DM, Goldman GH. RNAseq reveals hydrophobins that are involved in the adaptation of Aspergillus nidulans to lignocellulose. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:145. [PMID: 27437031 PMCID: PMC4950808 DOI: 10.1186/s13068-016-0558-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Accepted: 06/24/2016] [Indexed: 05/28/2023]
Abstract
BACKGROUND Sugarcane is one of the world's most profitable crops. Waste steam-exploded sugarcane bagasse (SEB) is a cheap, abundant, and renewable lignocellulosic feedstock for the next-generation biofuels. In nature, fungi seldom exist as planktonic cells, similar to those found in the nutrient-rich environment created within an industrial fermenter. Instead, fungi predominantly form biofilms that allow them to thrive in hostile environments. RESULTS In turn, we adopted an RNA-sequencing approach to interrogate how the model fungus, Aspergillus nidulans, adapts to SEB, revealing the induction of carbon starvation responses and the lignocellulolytic machinery, in addition to morphological adaptations. Genetic analyses showed the importance of hydrophobins for growth on SEB. The major hydrophobin, RodA, was retained within the fungal biofilm on SEB fibres. The StuA transcription factor that regulates fungal morphology was up-regulated during growth on SEB and controlled hydrophobin gene induction. The absence of the RodA or DewC hydrophobins reduced biofilm formation. The loss of a RodA or a functional StuA reduced the retention of the hydrolytic enzymes within the vicinity of the fungus. Hence, hydrophobins promote biofilm formation on SEB, and may enhance lignocellulose utilisation via promoting a compact substrate-enzyme-fungus structure. CONCLUSION This novel study highlights the importance of hydrophobins to the formation of biofilms and the efficient deconstruction of lignocellulose.
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Affiliation(s)
- Neil Andrew Brown
- />Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire UK
| | - Laure N. A. Ries
- />Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Thaila F. Reis
- />Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Ranjith Rajendran
- />Infection and Immunity Research Group, Glasgow Dental School, School of Medicine, College of Medical, Veterinary and Life Sciences, The University of Glasgow, Glasgow, UK
| | - Renato Augusto Corrêa dos Santos
- />Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, Campinas, SP CEP 13083-970 Brazil
| | - Gordon Ramage
- />Infection and Immunity Research Group, Glasgow Dental School, School of Medicine, College of Medical, Veterinary and Life Sciences, The University of Glasgow, Glasgow, UK
| | - Diego Mauricio Riaño-Pachón
- />Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, Campinas, SP CEP 13083-970 Brazil
| | - Gustavo H. Goldman
- />Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
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Meneau I, Coste AT, Sanglard D. Identification ofAspergillus fumigatusmultidrug transporter genes and their potential involvement in antifungal resistance. Med Mycol 2016; 54:616-27. [DOI: 10.1093/mmy/myw005] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 01/13/2016] [Indexed: 01/11/2023] Open
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34
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dos Reis TF, de Lima PBA, Parachin NS, Mingossi FB, de Castro Oliveira JV, Ries LNA, Goldman GH. Identification and characterization of putative xylose and cellobiose transporters in Aspergillus nidulans. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:204. [PMID: 27708711 PMCID: PMC5037631 DOI: 10.1186/s13068-016-0611-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 09/06/2016] [Indexed: 05/07/2023]
Abstract
BACKGROUND The conversion of lignocellulosic biomass to biofuels (second-generation biofuel production) is an environmentally friendlier alternative to petroleum-based energy sources. Enzymatic deconstruction of lignocellulose, catalyzed by filamentous fungi such as Aspergillus nidulans, releases a mixture of mono- and polysaccharides, including hexose (glucose) and pentose (xylose) sugars, cellodextrins (cellobiose), and xylooligosaccharides (xylobiose). These sugars can subsequently be fermented by yeast cells to ethanol. One of the major drawbacks in this process lies in the inability of yeast, such as Saccharomyces cerevisiae, to successfully internalize sugars other than glucose. The aim of this study was, therefore, to screen the genome of A. nidulans, which encodes a multitude of sugar transporters, for transporters able to internalize non-glucose sugars and characterize them when introduced into S. cerevisiae. RESULTS This work identified two proteins in A. nidulans, CltA and CltB, with roles in cellobiose transport and cellulose signaling, respectively. CltA, when introduced into S. cerevisiae, conferred growth on low and high concentrations of cellobiose. Deletion of cltB resulted in reduced growth and extracellular cellulase activity in A. nidulans in the presence of cellobiose. CltB, when introduced into S. cerevisiae, was not able to confer growth on cellobiose, suggesting that this protein is a sensor rather than a transporter. However, we have shown that the introduction of additional functional copies of CltB increases the growth in the presence of low concentrations of cellobiose, strongly indicating CltB is able to transport cellobiose. Furthermore, a previously identified glucose transporter, HxtB, was also found to be a major xylose transporter in A. nidulans. In S. cerevisiae, HxtB conferred growth on xylose which was accompanied by ethanol production. CONCLUSIONS This work identified a cellobiose transporter, a xylose transporter, and a putative cellulose transceptor in A. nidulans. This is the first time that a sensor role for a protein in A. nidulans has been proposed. Both transporters are also able to transport glucose, highlighting the preference of A. nidulans for this carbon source. This work provides a basis for future studies which aim at characterizing and/or genetically engineering Aspergillus spp. transporters, which, in addition to glucose, can also internalize other carbon sources, to improve transport and fermentation of non-glucose sugars in S. cerevisiae.
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Affiliation(s)
- Thaila Fernanda dos Reis
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, Ribeirão Preto, SP CEP 14040-903 Brazil
| | | | - Nádia Skorupa Parachin
- Departamento de Biologia Celular, Instituto de Biologia, Universidade de Brasília, Brasília, CEP 70910-900 Brazil
| | | | | | - Laure Nicolas Annick Ries
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, Ribeirão Preto, SP CEP 14040-903 Brazil
| | - Gustavo Henrique Goldman
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, Ribeirão Preto, SP CEP 14040-903 Brazil
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Fattahi A, Zaini F, Kordbacheh P, Rezaie S, Safara M, Fateh R, Farahyar S, Kanani A, Heidari M. Evaluation of mRNA Expression Levels of cyp51A and mdr1, Candidate Genes for Voriconazole Resistance in Aspergillus flavus. Jundishapur J Microbiol 2015; 8:e26990. [PMID: 26865941 PMCID: PMC4745269 DOI: 10.5812/jjm.26990] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 05/11/2015] [Accepted: 05/24/2015] [Indexed: 11/16/2022] Open
Abstract
Background: Voriconazole Resistance (VRC-R) in Aspergillus flavus isolates impacts the management of aspergillosis, since azoles are the first choice for prophylaxis and therapy. However, to the best of our knowledge, the mechanisms underlying voriconazole resistance are poorly understood. Objectives: The present study was designed to evaluate mRNA expression levels of cyp51A and mdr1 genes in voriconazole resistant A. flavus by a Real-Time Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) technique. Materials and Methods: Five A. flavus isolates with resistance to VRC were examined by a RT-PCR approach. Results: Four out of five isolates revealed cyp51A and mdr1 mRNA overexpression. Interestingly, the isolate, which was negative for cyp51A and mdr1 mRNA expression showed a high voriconazole Minimum Inhibitory Concentration (MIC). Furthermore, a computational-based analysis predicted that voriconazole resistance could be mediated through cooperation with a network protein interaction. Conclusions: Our experimental and in silico findings may provide new insight in the complex molecular pathways of drug resistance and also could assist design an efficient therapeutic strategy for aspergillosis treatment.
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Affiliation(s)
- Azam Fattahi
- Department of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Farideh Zaini
- Department of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Parivash Kordbacheh
- Department of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Sasan Rezaie
- Department of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Mahin Safara
- Department of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Roohollah Fateh
- Department of Microbiology and Immunology, Faculty of Medicine, Qom University of Medical Sciences, Qom, IR Iran
| | - Shirin Farahyar
- Department of Medical Mycology and Parasitology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, IR Iran
| | - Ali Kanani
- Department of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Mansour Heidari
- Department of Medical Genetics, Tehran University of Medical Sciences, Tehran, IR Iran
- Exprerimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, IR Iran
- Corresponding author: Mansour Heidari, Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, IR Iran. Tel/Fax: +98-218895 3005, E-mail:
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Brown NA, Dos Reis TF, Ries LNA, Caldana C, Mah JH, Yu JH, Macdonald JM, Goldman GH. G-protein coupled receptor-mediated nutrient sensing and developmental control in Aspergillus nidulans. Mol Microbiol 2015; 98:420-39. [PMID: 26179439 DOI: 10.1111/mmi.13135] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/14/2015] [Indexed: 12/31/2022]
Abstract
Nutrient sensing and utilisation are fundamental for all life forms. As heterotrophs, fungi have evolved a diverse range of mechanisms for sensing and taking up various nutrients. Despite its importance, only a limited number of nutrient receptors and their corresponding ligands have been identified in fungi. G-protein coupled receptors (GPCRs) are the largest family of transmembrane receptors. The Aspergillus nidulans genome encodes 16 putative GPCRs, but only a few have been functionally characterised. Our previous study showed the increased expression of an uncharacterised putative GPCR, gprH, during carbon starvation. GprH appears conserved throughout numerous filamentous fungi. Here, we reveal that GprH is a putative receptor involved in glucose and tryptophan sensing. The absence of GprH results in a reduction in cAMP levels and PKA activity upon adding glucose or tryptophan to starved cells. GprH is pre-formed in conidia and is increasingly active during carbon starvation, where it plays a role in glucose uptake and the recovery of hyphal growth. GprH also represses sexual development under conditions favouring sexual fruiting and during carbon starvation in submerged cultures. In summary, the GprH nutrient-sensing system functions upstream of the cAMP-PKA pathway, influences primary metabolism and hyphal growth, while represses sexual development in A. nidulans.
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Affiliation(s)
- Neil Andrew Brown
- Plant Biology and Crop Science, Rothamsted Research, Harpenden, Herts, AL5 2JQ, UK
| | - Thaila Fernanda Dos Reis
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | | | - Camila Caldana
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol - CTBE, Campinas, São Paulo, Brazil.,Max Planck Partnergroup at CTBE/CNPEM, Campinas, São Paulo, Brazil
| | - Jae-Hyung Mah
- Department of Food and Biotechnology, Korea University, Sejong, South Korea
| | - Jae-Hyuk Yu
- Department of Bacteriology, University of Wisconsin, Madison, WI, USA
| | - Jeffrey M Macdonald
- UNC Metabolomic Facility, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Gustavo Henrique Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil.,Laboratório Nacional de Ciência e Tecnologia do Bioetanol - CTBE, Campinas, São Paulo, Brazil
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Survival of the anaerobic fungus Orpinomyces sp. strain C1A after prolonged air exposure. Sci Rep 2014; 4:6892. [PMID: 25367149 PMCID: PMC4219153 DOI: 10.1038/srep06892] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 10/15/2014] [Indexed: 11/08/2022] Open
Abstract
Anaerobic fungi are efficient plant biomass degraders and represent promising agents for a variety of biotechnological applications. We evaluated the tolerance of an anaerobic fungal isolate, Orpinomyces sp. strain C1A, to air exposure in liquid media using soluble (cellobiose) and insoluble (dried switchgrass) substrates. Strain C1A grown on cellobiose survived for 11, and 13.5 hours following air exposure when grown under planktonic, and immobilized conditions, respectively. When grown on switchgrass media, strain C1A exhibited significantly enhanced air tolerance and survived for 168 hours. The genome of strain C1A lacked a catalase gene, but contained superoxide dismutase and glutathione peroxidase genes. Real time PCR analysis indicated that superoxide dismutase, but not glutathione peroxidase, exhibits a transient increase in expression level post aeration. Interestingly, the C1A superoxide dismutase gene of strain C1A appears to be most closely related to bacterial SODs, which implies its acquisition from a bacterial donor via cross kingdom horizontal gene transfer during Neocallimastigomycota evolution. We conclude that strain C1A utilizes multiple mechanisms to minimize the deleterious effects of air exposure such as physical protection and the production of oxidative stress enzymes.
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Brown NA, Dos Reis TF, Goinski AB, Savoldi M, Menino J, Almeida MT, Rodrigues F, Goldman GH. The Aspergillus nidulans signalling mucin MsbA regulates starvation responses, adhesion and affects cellulase secretion in response to environmental cues. Mol Microbiol 2014; 94:1103-1120. [PMID: 25294314 DOI: 10.1111/mmi.12820] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2014] [Indexed: 01/27/2023]
Abstract
In the heterogeneous semi-solid environment naturally occupied by lignocellulolytic fungi the majority of nutrients are locked away as insoluble plant biomass. Hence, lignocellulolytic fungi must actively search for, and attach to, a desirable source of nutrients. During growth on lignocellulose a period of carbon deprivation provokes carbon catabolite derepression and scavenging hydrolase secretion. Subsequently, starvation and/or contact sensing was hypothesized to play a role in lignocellulose attachment and degradation. In Aspergillus nidulans the extracellular signalling mucin, MsbA, influences growth under nutrient-poor conditions including lignocellulose. Cellulase secretion and activity was affected by MsbA via a mechanism that was independent of cellulase transcription. MsbA modulated both the cell wall integrity and filamentous growth MAPK pathways influencing adhesion, biofilm formation and secretion. The constitutive activation of MsbA subsequently enhanced cellulase activity by increasing the secretion of the cellobiohydrolase, CbhA, while improved substrate attachment and may contribute to an enhanced starvation response. Starvation and/or contact sensing therefore represents a new dimension to the already multifaceted regulation of cellulase activity.
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Affiliation(s)
- Neil Andrew Brown
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
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de Castro PA, Chen C, de Almeida RSC, Freitas FZ, Bertolini MC, Morais ER, Brown NA, Ramalho LNZ, Hagiwara D, Mitchell TK, Goldman GH. ChIP-seq reveals a role for CrzA in the Aspergillus fumigatus high-osmolarity glycerol response (HOG) signalling pathway. Mol Microbiol 2014; 94:655-74. [PMID: 25196896 DOI: 10.1111/mmi.12785] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2014] [Indexed: 12/28/2022]
Abstract
Aspergillus fumigatus is an opportunistic pathogen and allergen of mammals. Calcium signalling is essential for A. fumigatus pathogenicity and is regulated by the CrzA transcription factor. We used ChIP-seq (Chromatin Immunoprecipitation DNA sequencing) to explore CrzA gene targets in A. fumigatus. In total, 165 potential binding peaks including 102 directly regulated genes were identified, resulting in the prediction of the A[GT][CG]CA[AC][AG] CrzA-binding motif. The 102 CrzA putatively regulated genes exhibited a diverse array of functions. The phkB (Afu3g12530) histidine kinase and the sskB (Afu1g10940) MAP kinase kinase kinase of the HOG (high-osmolarity glycerol response) pathway were regulated by CrzA. Several members of the two-component system (TCS) and the HOG pathway were more sensitive to calcium. CrzA::GFP was translocated to the nucleus upon osmotic stress. CrzA is important for the phosphorylation of the SakA MAPK in response to osmotic shock. The ΔsskB was more sensitive to CaCl2 , NaCl, and paraquat stress, while being avirulent in a murine model of invasive pulmonary aspergillosis. The presence of CaCl2 and osmotic stresses resulted in synergistic inhibition of ΔcrzA and ΔsskB growth. These results suggest there is a genetic interaction between the A. fumigatus calcineurin-CrzA and HOG pathway that is essential for full virulence.
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Affiliation(s)
- Patrícia A de Castro
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
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de Castro PA, Chiaratto J, Winkelströter LK, Bom VLP, Ramalho LNZ, Goldman MHS, Brown NA, Goldman GH. The involvement of the Mid1/Cch1/Yvc1 calcium channels in Aspergillus fumigatus virulence. PLoS One 2014; 9:e103957. [PMID: 25083783 PMCID: PMC4118995 DOI: 10.1371/journal.pone.0103957] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 07/03/2014] [Indexed: 11/30/2022] Open
Abstract
Aspergillus fumigatus is a major opportunistic pathogen and allergen of mammals. Calcium homeostasis and signaling is essential for numerous biological processes and also influences A. fumigatus pathogenicity. The presented study characterized the function of the A. fumigatus homologues of three Saccharomyces cerevisiae calcium channels, voltage-gated Cch1, stretch-activated Mid1 and vacuolar Yvc1. The A. fumigatus calcium channels cchA, midA and yvcA were regulated at transcriptional level by increased calcium levels. The YvcA::GFP fusion protein localized to the vacuoles. Both ΔcchA and ΔmidA mutant strains showed reduced radial growth rate in nutrient-poor minimal media. Interestingly, this growth defect in the ΔcchA strain was rescued by the exogenous addition of CaCl2. The ΔcchA, ΔmidA, and ΔcchA ΔmidA strains were also sensitive to the oxidative stress inducer, paraquat. Restriction of external Ca2+ through the addition of the Ca2+-chelator EGTA impacted upon the growth of the ΔcchA and ΔmidA strains. All the A. fumigatus ΔcchA, ΔmidA, and ΔyvcA strains demonstrated attenuated virulence in a neutropenic murine model of invasive pulmonary aspergillosis. Infection with the parental strain resulted in a 100% mortality rate at 15 days post-infection, while the mortality rate of the ΔcchA, ΔmidA, and ΔyvcA strains after 15 days post-infection was only 25%. Collectively, this investigation strongly indicates that CchA, MidA, and YvcA play a role in A. fumigatus calcium homeostasis and virulence.
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Affiliation(s)
- Patrícia Alves de Castro
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Jéssica Chiaratto
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Lizziane K. Winkelströter
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Vinícius Leite Pedro Bom
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | | | - Maria Helena S. Goldman
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Neil Andrew Brown
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Gustavo H. Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
- National Laboratory of Science and Technology of Bioethanol (CTBE), Campinas, Brazil
- * E-mail:
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Colabardini AC, Ries LNA, Brown NA, dos Reis TF, Savoldi M, Goldman MHS, Menino JF, Rodrigues F, Goldman GH. Functional characterization of a xylose transporter in Aspergillus nidulans. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:46. [PMID: 24690493 PMCID: PMC4021826 DOI: 10.1186/1754-6834-7-46] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Accepted: 03/13/2014] [Indexed: 05/06/2023]
Abstract
BACKGROUND The production of bioethanol from lignocellulosic feedstocks will only become economically feasible when the majority of cellulosic and hemicellulosic biopolymers can be efficiently converted into bioethanol. The main component of cellulose is glucose, whereas hemicelluloses mainly consist of pentose sugars such as D-xylose and L-arabinose. The genomes of filamentous fungi such as A. nidulans encode a multiplicity of sugar transporters with broad affinities for hexose and pentose sugars. Saccharomyces cerevisiae, which has a long history of use in industrial fermentation processes, is not able to efficiently transport or metabolize pentose sugars (e.g. xylose). Subsequently, the aim of this study was to identify xylose-transporters from A. nidulans, as potential candidates for introduction into S. cerevisiae in order to improve xylose utilization. RESULTS In this study, we identified the A. nidulans xtrD (xylose transporter) gene, which encodes a Major Facilitator Superfamily (MFS) transporter, and which was specifically induced at the transcriptional level by xylose in a XlnR-dependent manner, while being partially repressed by glucose in a CreA-dependent manner. We evaluated the ability of xtrD to functionally complement the S. cerevisiae EBY.VW4000 strain which is unable to grow on glucose, fructose, mannose or galactose as single carbon source. In S. cerevisiae, XtrD was targeted to the plasma membrane and its expression was able to restore growth on xylose, glucose, galactose, and mannose as single carbon sources, indicating that this transporter accepts multiple sugars as a substrate. XtrD has a high affinity for xylose, and may be a high affinity xylose transporter. We were able to select a S. cerevisiae mutant strain that had increased xylose transport when expressing the xtrD gene. CONCLUSIONS This study characterized the regulation and substrate specificity of an A. nidulans transporter that represents a good candidate for further directed mutagenesis. Investigation into the area of sugar transport in fungi presents a crucial step for improving the S. cerevisiae xylose metabolism. Moreover, we have demonstrated that the introduction of adaptive mutations beyond the introduced xylose utilization genes is able to improve S. cerevisiae xylose metabolism.
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Affiliation(s)
- Ana Cristina Colabardini
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903 Ribeirão Preto, São Paulo, Brazil
| | - Laure Nicolas Annick Ries
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903 Ribeirão Preto, São Paulo, Brazil
| | - Neil Andrew Brown
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903 Ribeirão Preto, São Paulo, Brazil
| | - Thaila Fernanda dos Reis
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903 Ribeirão Preto, São Paulo, Brazil
| | - Marcela Savoldi
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903 Ribeirão Preto, São Paulo, Brazil
| | - Maria Helena S Goldman
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - João Filipe Menino
- ICVS/3B’s - PT Government Associate Laboratory, Braga/Guimarães, Portugal and Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
| | - Fernando Rodrigues
- ICVS/3B’s - PT Government Associate Laboratory, Braga/Guimarães, Portugal and Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
| | - Gustavo Henrique Goldman
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903 Ribeirão Preto, São Paulo, Brazil
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol – CTBE, Caixa Postal 6170 13083-970, Campinas, São Paulo, Brazil
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The Aspergillus nidulans ATM kinase regulates mitochondrial function, glucose uptake and the carbon starvation response. G3-GENES GENOMES GENETICS 2014; 4:49-62. [PMID: 24192833 PMCID: PMC3887539 DOI: 10.1534/g3.113.008607] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Mitochondria supply cellular energy and also perform a role in the adaptation to metabolic stress. In mammals, the ataxia-telangiectasia mutated (ATM) kinase acts as a redox sensor controlling mitochondrial function. Subsequently, transcriptomic and genetic studies were utilized to elucidate the role played by a fungal ATM homolog during carbon starvation. In Aspergillus nidulans, AtmA was shown to control mitochondrial function and glucose uptake. Carbon starvation responses that are regulated by target of rapamycin (TOR) were shown to be AtmA-dependent, including autophagy and hydrolytic enzyme secretion. AtmA also regulated a p53-like transcription factor, XprG, inhibiting starvation-induced XprG-dependent protease secretion and cell death. Thus, AtmA possibly represents a direct or indirect link between mitochondrial stress, metabolism, and growth through the influence of TOR and XprG function. The coordination of cell growth and division with nutrient availability is crucial for all microorganisms to successfully proliferate in a heterogeneous environment. Mitochondria supply cellular energy but also perform a role in the adaptation to metabolic stress and the cross-talk between prosurvival and prodeath pathways. The present study of Aspergillus nidulans demonstrated that AtmA also controlled mitochondrial mass, function, and oxidative phosphorylation, which directly or indirectly influenced glucose uptake. Carbon starvation responses, including autophagy, shifting metabolism to the glyoxylate cycle, and the secretion of carbon scavenging enzymes were AtmA-dependent. Transcriptomic profiling of the carbon starvation response demonstrated how TOR signaling and the retrograde response, which signals mitochondrial dysfunction, were directly or indirectly influenced by AtmA. The AtmA kinase was also shown to influence a p53-like transcription factor, inhibiting starvation-induced XprG-dependent protease secretion and cell death. Therefore, in response to metabolic stress, AtmA appears to perform a role in the regulation of TOR signaling, involving the retrograde and SnfA pathways. Thus, AtmA may represent a link between mitochondrial function and cell cycle or growth, possibly through the influence of the TOR and XprG function.
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dos Reis TF, Menino JF, Bom VLP, Brown NA, Colabardini AC, Savoldi M, Goldman MHS, Rodrigues F, Goldman GH. Identification of glucose transporters in Aspergillus nidulans. PLoS One 2013; 8:e81412. [PMID: 24282591 PMCID: PMC3839997 DOI: 10.1371/journal.pone.0081412] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 10/12/2013] [Indexed: 11/18/2022] Open
Abstract
To characterize the mechanisms involved in glucose transport, in the filamentous fungus Aspergillus nidulans, we have identified four glucose transporter encoding genes hxtB-E. We evaluated the ability of hxtB-E to functionally complement the Saccharomyces cerevisiae EBY.VW4000 strain that is unable to grow on glucose, fructose, mannose or galactose as single carbon source. In S. cerevisiae HxtB-E were targeted to the plasma membrane. The expression of HxtB, HxtC and HxtE was able to restore growth on glucose, fructose, mannose or galactose, indicating that these transporters accept multiple sugars as a substrate through an energy dependent process. A tenfold excess of unlabeled maltose, galactose, fructose, and mannose were able to inhibit glucose uptake to different levels (50 to 80 %) in these s. cerevisiae complemented strains. Moreover, experiments with cyanide-m-chlorophenylhydrazone (CCCP), strongly suggest that hxtB, -C, and -E mediate glucose transport via active proton symport. The A. nidulans ΔhxtB, ΔhxtC or ΔhxtE null mutants showed ~2.5-fold reduction in the affinity for glucose, while ΔhxtB and -C also showed a 2-fold reduction in the capacity for glucose uptake. The ΔhxtD mutant had a 7.8-fold reduction in affinity, but a 3-fold increase in the capacity for glucose uptake. However, only the ΔhxtB mutant strain showed a detectable decreased rate of glucose consumption at low concentrations and an increased resistance to 2-deoxyglucose.
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Affiliation(s)
- Thaila Fernanda dos Reis
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - João Filipe Menino
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
| | - Vinícius Leite Pedro Bom
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Neil Andrew Brown
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Ana Cristina Colabardini
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Marcela Savoldi
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Maria Helena S. Goldman
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Fernando Rodrigues
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
| | - Gustavo Henrique Goldman
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol – CTBE, Campinas, São Paulo, Brazil
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
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The influence of Aspergillus niger transcription factors AraR and XlnR in the gene expression during growth in D-xylose, L-arabinose and steam-exploded sugarcane bagasse. Fungal Genet Biol 2013; 60:29-45. [PMID: 23892063 DOI: 10.1016/j.fgb.2013.07.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 07/03/2013] [Accepted: 07/17/2013] [Indexed: 12/29/2022]
Abstract
The interest in the conversion of plant biomass to renewable fuels such as bioethanol has led to an increased investigation into the processes regulating biomass saccharification. The filamentous fungus Aspergillus niger is an important microorganism capable of producing a wide variety of plant biomass degrading enzymes. In A. niger the transcriptional activator XlnR and its close homolog, AraR, controls the main (hemi-)cellulolytic system responsible for plant polysaccharide degradation. Sugarcane is used worldwide as a feedstock for sugar and ethanol production, while the lignocellulosic residual bagasse can be used in different industrial applications, including ethanol production. The use of pentose sugars from hemicelluloses represents an opportunity to further increase production efficiencies. In the present study, we describe a global gene expression analysis of A. niger XlnR- and AraR-deficient mutant strains, grown on a D-xylose/L-arabinose monosaccharide mixture and steam-exploded sugarcane bagasse. Different gene sets of CAZy enzymes and sugar transporters were shown to be individually or dually regulated by XlnR and AraR, with XlnR appearing to be the major regulator on complex polysaccharides. Our study contributes to understanding of the complex regulatory mechanisms responsible for plant polysaccharide-degrading gene expression, and opens new possibilities for the engineering of fungi able to produce more efficient enzymatic cocktails to be used in biofuel production.
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Genetic bypass of Aspergillus nidulans crzA function in calcium homeostasis. G3-GENES GENOMES GENETICS 2013; 3:1129-41. [PMID: 23665873 PMCID: PMC3704241 DOI: 10.1534/g3.113.005983] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
After dephosphorylation by the phosphatase calcineurin, the fungal transcription factor CrzA enters the nucleus and activates the transcription of genes responsible for calcium homeostasis and many other calcium-regulated activities. A lack of CrzA confers calcium-sensitivity to the filamentous fungus Aspergillus nidulans. To further understand calcium signaling in filamentous fungi and to identify genes that interact genetically with CrzA, we selected for mutations that were able to suppress crzAΔ calcium intolerance and identified three genes. Through genetic mapping, gene sequencing, and mutant rescue, we were able to identify these as cnaB (encoding the calcineurin regulatory subunit), folA (encoding an enzyme involved in folic acid biosynthesis, dihydroneopterin aldolase), and scrC (suppression of crzA-, encoding a hypothetical protein). By using a calcium indicator, Fluo-3, we were able to determine that the wild-type and the suppressor strains were either able to regulate intracellular calcium levels or were able to take up and or store calcium correctly. The increased expression of calcium transporters, pmcA and/or pmcB, in suppressor mutants possibly enabled tolerance to high levels of calcium. Our results suggest that a cnaB suppressor mutation confers calcium tolerance to crzAΔ strains through restoration of calcium homeostasis. These results stress that in A. nidulans there are calcineurin-dependent and CrzA-independent pathways. In addition, it is possible that CrzA is able to contribute to the modulation of folic acid biosynthesis.
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Brown NA, de Gouvea PF, Krohn NG, Savoldi M, Goldman GH. Functional characterisation of the non-essential protein kinases and phosphatases regulating Aspergillus nidulans hydrolytic enzyme production. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:91. [PMID: 23800192 PMCID: PMC3698209 DOI: 10.1186/1754-6834-6-91] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 06/18/2013] [Indexed: 05/06/2023]
Abstract
BACKGROUND Despite recent advances in the understanding of lignocellulolytic enzyme regulation, less is known about how different carbon sources are sensed and the signaling cascades that result in the adaptation of cellular metabolism and hydrolase secretion. Therefore, the role played by non-essential protein kinases (NPK) and phosphatases (NPP) in the sensing of carbon and/or energetic status was investigated in the model filamentous fungus Aspergillus nidulans. RESULTS Eleven NPKs and seven NPPs were identified as being involved in cellulase, and in some cases also hemicellulase, production in A. nidulans. The regulation of CreA-mediated carbon catabolite repression (CCR) in the parental strain was determined by fluorescence microscopy, utilising a CreA::GFP fusion protein. The sensing of phosphorylated glucose, via the RAS signalling pathway induced CreA repression, while carbon starvation resulted in derepression. Growth on cellulose represented carbon starvation and derepressing conditions. The involvement of the identified NPKs in the regulation of cellulose-induced responses and CreA derepression was assessed by genome-wide transcriptomics (GEO accession 47810). CreA::GFP localisation and the restoration of endocellulase activity via the introduction of the ∆creA mutation, was assessed in the NPK-deficient backgrounds. The absence of either the schA or snfA kinase dramatically reduced cellulose-induced transcriptional responses, including the expression of hydrolytic enzymes and transporters. The mechanism by which these two NPKs controlled gene transcription was identified, as the NPK-deficient mutants were not able to unlock CreA-mediated carbon catabolite repression under derepressing conditions, such as carbon starvation or growth on cellulose. CONCLUSIONS Collectively, this study identified multiple kinases and phosphatases involved in the sensing of carbon and/or energetic status, while demonstrating the overlapping, synergistic roles of schA and snfA in the regulation of CreA derepression and hydrolytic enzyme production in A. nidulans. The importance of a carbon starvation-induced signal for CreA derepression, permitting transcriptional activator binding, appeared paramount for hydrolase secretion.
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Affiliation(s)
- Neil Andrew Brown
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Paula Fagundes de Gouvea
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Nádia Graciele Krohn
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Marcela Savoldi
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Gustavo Henrique Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Campinas, Brazil
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Colabardini AC, Brown NA, Savoldi M, Goldman MHS, Goldman GH. Functional characterization of Aspergillus nidulans ypkA, a homologue of the mammalian kinase SGK. PLoS One 2013; 8:e57630. [PMID: 23472095 PMCID: PMC3589345 DOI: 10.1371/journal.pone.0057630] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 01/23/2013] [Indexed: 11/19/2022] Open
Abstract
The serum- and glucocorticoid-regulated protein kinase (SGK) is an AGC kinase involved in signal cascades regulated by glucocorticoid hormones and serum in mammals. The Saccharomyces cerevisiae ypk1 and ypk2 genes were identified as SGK homologues and Ypk1 was shown to regulate the balance of sphingolipids between the inner and outer plasma membrane. This investigation characterized the Aspergillus nidulans YPK1 homologue, YpkA, representing the first filamentous fungal YPK1 homologue. Two conditional mutant strains were constructed by replacing the endogenous ypk1 promoter with two different regulatable promoters, alcA (from the alcohol dehydrogenase gene) and niiA (from the nitrate reductase gene). Both constructs confirmed that ypkA was an essential gene in A. nidulans. Repression of ypkA caused decreased radial growth, a delay in conidial germination, deficient polar axis establishment, intense branching during late stages of growth, a lack of asexual spores, and a terminal phenotype. Membrane lipid polarization, endocytosis, eisosomes and vacuolar distribution were also affected by ypkA repression, suggesting that YpkA plays a role in hyphal morphogenesis via coordinating the delivery of cell membrane and wall constituents to the hyphal apex. The A. nidulans Pkh1 homologue pkhA was also shown to be an essential gene, and preliminary genetic analysis suggested that the ypkA gene is not directly downstream of pkhA or epistatic to pkhA, rather, ypkA and pkhA are genetically independent or in parallel. BarA is a homologue of the yeast Lag1 acyl-CoA-dependent ceramide synthase, which catalyzes the condensation of phytosphingosine with a fatty acyl-CoA to form phytoceramide. When barA was absent, ypkA repression was lethal to the cell. Therefore, there appears to be a genetic interaction between ypkA, barA, and the sphingolipid synthesis. Transcriptional profiling of ypkA overexpression and down-regulation revealed several putative YpkA targets associated with the observed phenotypes.
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Affiliation(s)
- Ana Cristina Colabardini
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Neil Andrew Brown
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Marcela Savoldi
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Maria Helena S. Goldman
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Gustavo Henrique Goldman
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol – CTBE, São Paulo, Brazil
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
- * E-mail: address:
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SAGA complex components and acetate repression in Aspergillus nidulans. G3-GENES GENOMES GENETICS 2012; 2:1357-67. [PMID: 23173087 PMCID: PMC3484666 DOI: 10.1534/g3.112.003913] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 09/05/2012] [Indexed: 11/30/2022]
Abstract
Alongside the well-established carbon catabolite repression by glucose and other sugars, acetate causes repression in Aspergillus nidulans. Mutations in creA, encoding the transcriptional repressor involved in glucose repression, also affect acetate repression, but mutations in creB or creC, encoding components of a deubiquitination system, do not. To understand the effects of acetate, we used a mutational screen that was similar to screens that uncovered mutations in creA, creB, and creC, except that glucose was replaced by acetate to identify mutations that were affected for repression by acetate but not by glucose. We uncovered mutations in acdX, homologous to the yeast SAGA component gene SPT8, which in growth tests showed derepression for acetate repression but not for glucose repression. We also made mutations in sptC, homologous to the yeast SAGA component gene SPT3, which showed a similar phenotype. We found that acetate repression is complex, and analysis of facA mutations (lacking acetyl CoA synthetase) indicates that acetate metabolism is required for repression of some systems (proline metabolism) but not for others (acetamide metabolism). Although plate tests indicated that acdX- and sptC-null mutations led to derepressed alcohol dehydrogenase activity, reverse-transcription quantitative real-time polymerase chain reaction showed no derepression of alcA or aldA but rather elevated induced levels. Our results indicate that acetate repression is due to repression via CreA together with metabolic changes rather than due to an independent regulatory control mechanism.
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de Castro PA, Savoldi M, Bonatto D, Malavazi I, Goldman MHS, Berretta AA, Goldman GH. Transcriptional profiling of Saccharomyces cerevisiae exposed to propolis. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2012; 12:194. [PMID: 23092287 PMCID: PMC3598864 DOI: 10.1186/1472-6882-12-194] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 10/17/2012] [Indexed: 11/10/2022]
Abstract
BACKGROUND Propolis is a natural product of plant resins collected by honeybees (Apis mellifera) from various plant sources. Our previous studies indicated that propolis sensitivity is dependent on the mitochondrial function and that vacuolar acidification and autophagy are important for yeast cell death caused by propolis. Here, we extended our understanding of propolis-mediated cell death in the yeast Saccharomyces cerevisiae by applying systems biology tools to analyze the transcriptional profiling of cells exposed to propolis. METHODS We have used transcriptional profiling of S. cerevisiae exposed to propolis. We validated our findings by using real-time PCR of selected genes. Systems biology tools (physical protein-protein interaction [PPPI] network) were applied to analyse the propolis-induced transcriptional bevavior, aiming to identify which pathways are modulated by propolis in S. cerevisiae and potentially influencing cell death. RESULTS We were able to observe 1,339 genes modulated in at least one time point when compared to the reference time (propolis untreated samples) (t-test, p-value 0.01). Enrichment analysis performed by Gene Ontology (GO) Term finder tool showed enrichment for several biological categories among the genes up-regulated in the microarray hybridization such as transport and transmembrane transport and response to stress. Real-time RT-PCR analysis of selected genes showed by our microarray hybridization approach was capable of providing information about S. cerevisiae gene expression modulation with a considerably high level of confidence. Finally, a physical protein-protein (PPPI) network design and global topological analysis stressed the importance of these pathways in response of S. cerevisiae to propolis and were correlated with the transcriptional data obtained thorough the microarray analysis. CONCLUSIONS In summary, our data indicate that propolis is largely affecting several pathways in the eukaryotic cell. However, the most prominent pathways are related to oxidative stress, mitochondrial electron transport chain, vacuolar acidification, regulation of macroautophagy associated with protein target to vacuole, cellular response to starvation, and negative regulation of transcription from RNA polymerase II promoter. Our work emphasizes again the importance of S. cerevisiae as a model system to understand at molecular level the mechanism whereby propolis causes cell death in this organism at the concentration herein tested. Our study is the first one that investigates systematically by using functional genomics how propolis influences and modulates the mRNA abundance of an organism and may stimulate further work on the propolis-mediated cell death mechanisms in fungi.
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Pereira AF, Sá LL, Reis FHZ, Cardoso FC, Alberici RM, Prado IMR, Eberlin MN, Uyemura SA, Curti C, Alberici LC. Administration of a murine diet supplemented with conjugated linoleic acid increases the expression and activity of hepatic uncoupling proteins. J Bioenerg Biomembr 2012; 44:587-96. [PMID: 22864539 DOI: 10.1007/s10863-012-9463-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Accepted: 07/10/2012] [Indexed: 01/13/2023]
Abstract
Daily intake of conjugated linoleic acid (CLA) has been shown to reduce body fat accumulation and to increase body metabolism; this latter effect has been often associated with the up-regulation of uncoupling proteins (UCPs). Here we addressed the effects of a CLA-supplemented murine diet (~2 % CLA mixture, cis-9, trans-10 and trans-10, cis-12 isomers; 45 % of each isomer on alternating days) on mitochondrial energetics, UCP2 expression/activity in the liver and other associated morphological and functional parameters, in C57BL/6 mice. Diet supplementation with CLA reduced both lipid accumulation in adipose tissues and triacylglycerol plasma levels, but did not augment hepatic lipid storage. Livers of mice fed a diet supplemented with CLA showed high UCP2 mRNA levels and the isolated hepatic mitochondria showed indications of UCP activity: in the presence of guanosine diphosphate, the higher stimulation of respiration promoted by linoleic acid in mitochondria from the CLA mice was almost completely reduced to the level of the stimulation from the control mice. Despite the increased generation of reactive oxygen species through oxi-reduction reactions involving NAD(+)/NADH in the Krebs cycle, no oxidative stress was observed in the liver. In addition, in the absence of free fatty acids, basal respiration rates and the phosphorylating efficiency of mitochondria were preserved. These results indicate a beneficial and secure dose of CLA for diet supplementation in mice, which induces UCP2 overexpression and UCP activity in mitochondria while preserving the lipid composition and redox state of the liver.
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Affiliation(s)
- Amanda F Pereira
- Departamento de Física e Química, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
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