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Nong Y, Wang F, Shuai F, Chen S. Morphology, Development, and Pigment Production of Talaromyces marneffei are Diversely Modulated Under Physiologically Relevant Growth Conditions. Curr Microbiol 2024; 81:119. [PMID: 38526674 DOI: 10.1007/s00284-024-03623-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 01/22/2024] [Indexed: 03/27/2024]
Abstract
Talaromyces marneffei is an opportunistic pathogenic fungus that mainly affects HIV-positive individuals endemic to Southeast Asia and China. Increasing efforts have been made in the pathogenic mechanism and host interactions understanding of this pathogen in the last two decades; however, there are still no conclusions on how T. marneffei was transmitted from the donor bamboo rats to humans. A perception that the failure of fungus isolation from soil was attributed to the low salt tolerance of T. marneffei. Therefore, the effect of environmental fluctuations in fungal growth and development is fundamental for the characterization of its origin and fungal biology understanding. Herein, we characterized high osmolarity, pH, metal ions, nutrients, and oxidative stress have versatile effects on T. marneffei hyphal or yeast growth, conidia generation, and pigment production. Among these, high pH, low glucose amounts, and the inorganic nitrogen ammonium tartrate stimulated the red pigment production, whereas high osmolarity, high pH, and the inorganic nitrogen sodium nitrate could significantly accelerate the conidia generation. Specifically, zinc starvation repressed conidia generation and prevented the wrinkled yeast colony formation, indicating the function of zinc regulators in pathogenicity regulation. Since conidia are recognized as the infectious propagules, the effects characterization of different environmental factors in T. marneffei morphology in this work will not only expand the growth and pathogenic biology understanding of the fungus but also provide more clues for the T. marneffei infection transmission origin investigation.
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Affiliation(s)
- Yuan Nong
- Guangxi University of Chinese Medicine, Nanning, 530200, Guangxi, China
| | - Fang Wang
- Intensive Care Unit, Shenzhen Key Laboratory of Microbiology in Genomic Modification & Editing and Application, Shenzhen University Medical School, Shenzhen Institute of Translational Medicine, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University, 518035, Shenzhen, China.
| | - Feifei Shuai
- Intensive Care Unit, Shenzhen Key Laboratory of Microbiology in Genomic Modification & Editing and Application, Shenzhen University Medical School, Shenzhen Institute of Translational Medicine, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University, 518035, Shenzhen, China
| | - Shi Chen
- Guangxi University of Chinese Medicine, Nanning, 530200, Guangxi, China.
- Intensive Care Unit, Shenzhen Key Laboratory of Microbiology in Genomic Modification & Editing and Application, Shenzhen University Medical School, Shenzhen Institute of Translational Medicine, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University, 518035, Shenzhen, China.
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Pruksaphon K, Amsri A, Thammasit P, Nosanchuk JD, Youngchim S. Extracellular vesicles derived from Talaromyces marneffei contain immunogenic compounds and modulate THP-1 macrophage responses. Front Immunol 2023; 14:1192326. [PMID: 37457708 PMCID: PMC10339390 DOI: 10.3389/fimmu.2023.1192326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 06/08/2023] [Indexed: 07/18/2023] Open
Abstract
Pathogenic eukaryotes including fungi release extracellular vesicles (EVs) which are composed of a variety of bioactive components, including peptides, nucleic acids, polysaccharides, and membrane lipids. EVs contain virulence-associated molecules suggesting a crucial role of these structures in disease pathogenesis. EVs derived from the pathogenic yeast phase of Talaromyces (Penicillium) marneffei, a causative agent of systemic opportunistic mycoses "talaromycosis," were studied for their immunogenic components and immunomodulatory properties. Some important virulence factors in EVs including fungal melanin and yeast phase specific mannoprotein were determined by immunoblotting. Furthermore, fluorescence microscopy revealed that T. marneffei EVs were internalized by THP-1 human macrophages. Co-incubation of T. marneffei EVs with THP-1 human macrophages resulted in increased levels of supernatant interleukin (IL)-1β, IL-6 and IL-10. The expression of THP-1 macrophage surface CD86 was significantly increased after exposed to T. marneffei EVs. These findings support the hypothesis that fungal EVs play an important role in macrophage "classical" M1 polarization. T. marneffei EVs preparations also increased phagocytosis, suggesting that EV components stimulate THP-1 macrophages to produce effective antimicrobial compounds. In addition, T. marneffei EVs stimulated THP-1 macrophages were more effective at killing T. marneffei conidia. These results indicate that T. marneffei EVs can potently modulate macrophage functions, resulting in the activation of these innate immune cells to enhance their antimicrobial activity.
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Affiliation(s)
- Kritsada Pruksaphon
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Artid Amsri
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Patcharin Thammasit
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Joshua D. Nosanchuk
- Department of Medicine (Division of Infectious Diseases) and Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, United States
| | - Sirida Youngchim
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
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Wang F, Han R, Chen S. An Overlooked and Underrated Endemic Mycosis-Talaromycosis and the Pathogenic Fungus Talaromyces marneffei. Clin Microbiol Rev 2023; 36:e0005122. [PMID: 36648228 PMCID: PMC10035316 DOI: 10.1128/cmr.00051-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Talaromycosis is an invasive mycosis endemic in tropical and subtropical Asia and is caused by the pathogenic fungus Talaromyces marneffei. Approximately 17,300 cases of T. marneffei infection are diagnosed annually, and the reported mortality rate is extremely high (~1/3). Despite the devastating impact of talaromycosis on immunocompromised individuals, particularly HIV-positive persons, and the increase in reported occurrences in HIV-uninfected persons, diagnostic and therapeutic approaches for talaromycosis have received far too little attention worldwide. In 2021, scientists living in countries where talaromycosis is endemic raised a global demand for it to be recognized as a neglected tropical disease. Therefore, T. marneffei and the infectious disease induced by this fungus must be treated with concern. T. marneffei is a thermally dimorphic saprophytic fungus with a complicated mycological growth process that may produce various cell types in its life cycle, including conidia, hyphae, and yeast, all of which are associated with its pathogenicity. However, understanding of the pathogenic mechanism of T. marneffei has been limited until recently. To achieve a holistic view of T. marneffei and talaromycosis, the current knowledge about talaromycosis and research breakthroughs regarding T. marneffei growth biology are discussed in this review, along with the interaction of the fungus with environmental stimuli and the host immune response to fungal infection. Importantly, the future research directions required for understanding this serious infection and its causative pathogenic fungus are also emphasized to identify solutions that will alleviate the suffering of susceptible individuals worldwide.
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Affiliation(s)
- Fang Wang
- Intensive Care Unit, Biomedical Research Center, Shenzhen Institute of Translational Medicine, Health Science Center, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People’s Hospital, Shenzhen, China
| | - RunHua Han
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Shi Chen
- Intensive Care Unit, Biomedical Research Center, Shenzhen Institute of Translational Medicine, Health Science Center, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People’s Hospital, Shenzhen, China
- Department of Burn and Plastic Surgery, Biomedical Research Center, Shenzhen Institute of Translational Medicine, Health Science Center, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People’s Hospital, Shenzhen, China
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New Insights in Dermatophytes: Microsporum spp. and Nannizzia spp. CURRENT TROPICAL MEDICINE REPORTS 2022. [DOI: 10.1007/s40475-022-00252-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Höft MA, Duvenage L, Hoving JC. Key thermally dimorphic fungal pathogens: shaping host immunity. Open Biol 2022; 12:210219. [PMID: 35259948 PMCID: PMC8905152 DOI: 10.1098/rsob.210219] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 02/09/2022] [Indexed: 01/09/2023] Open
Abstract
Exposure to fungal pathogens from the environment is inevitable and with the number of at-risk populations increasing, the prevalence of invasive fungal infection is on the rise. An interesting group of fungal organisms known as thermally dimorphic fungi predominantly infects immunocompromised individuals. These potential pathogens are intriguing in that they survive in the environment in one form, mycelial phase, but when entering the host, they are triggered by the change in temperature to switch to a new pathogenic form. Considering the growing prevalence of infection and the need for improved diagnostic and treatment approaches, studies identifying key components of fungal recognition and the innate immune response to these pathogens will significantly contribute to our understanding of disease progression. This review focuses on key endemic dimorphic fungal pathogens that significantly contribute to disease, including Histoplasma, Coccidioides and Talaromyces species. We briefly describe their prevalence, route of infection and clinical presentation. Importantly, we have reviewed the major fungal cell wall components of these dimorphic fungi, the host pattern recognition receptors responsible for recognition and important innate immune responses supporting adaptive immunity and fungal clearance or the failure thereof.
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Affiliation(s)
- Maxine A. Höft
- CMM AFRICA Medical Mycology Research Unit, Institute of Infectious Diseases and Molecular Medicine (IDM), University of Cape Town, Cape Town 7925, South Africa
- Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
- MRC Centre for Medical Mycology at the University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
| | - Lucian Duvenage
- CMM AFRICA Medical Mycology Research Unit, Institute of Infectious Diseases and Molecular Medicine (IDM), University of Cape Town, Cape Town 7925, South Africa
- Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
- MRC Centre for Medical Mycology at the University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
| | - J. Claire Hoving
- CMM AFRICA Medical Mycology Research Unit, Institute of Infectious Diseases and Molecular Medicine (IDM), University of Cape Town, Cape Town 7925, South Africa
- Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
- MRC Centre for Medical Mycology at the University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
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Talaromyces marneffei Infection: Virulence, Intracellular Lifestyle and Host Defense Mechanisms. J Fungi (Basel) 2022; 8:jof8020200. [PMID: 35205954 PMCID: PMC8880324 DOI: 10.3390/jof8020200] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 02/14/2022] [Accepted: 02/18/2022] [Indexed: 12/02/2022] Open
Abstract
Talaromycosis (Penicilliosis) is an opportunistic mycosis caused by the thermally dimorphic fungus Talaromyces (Penicillium) marneffei. Similar to other major causes of systemic mycoses, the extent of disease and outcomes are the results of complex interactions between this opportunistic human pathogen and a host’s immune response. This review will highlight the current knowledge regarding the dynamic interaction between T. marneffei and mammalian hosts, particularly highlighting important aspects of virulence factors, intracellular lifestyle and the mechanisms of immune defense as well as the strategies of the pathogen for manipulating and evading host immune cells.
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Fungal Keratitis in Northern Thailand: Spectrum of Agents, Risk Factors and Putative Virulence Factors. J Fungi (Basel) 2021; 7:jof7060475. [PMID: 34208353 PMCID: PMC8231135 DOI: 10.3390/jof7060475] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 06/04/2021] [Accepted: 06/09/2021] [Indexed: 01/09/2023] Open
Abstract
Fungal keratitis (FK) is a serious ocular infection that can result in various degrees of vision loss, including blindness. The aim of the study was to identify and retrospectively review all FK cases diagnosed between August 2012 and December 2020 at a tertiary care hospital in northern Thailand with a specific focus on epidemiologic features, including season, patient sex and age, the spectrum of pathogens, and presence of certain putative virulence factors. Of 1237 patients with corneal ulcers, 294 (23.8%) were confirmed by direct microscopic examination and/or fungal culture. For the positive cases, direct examinations of Calcofluor white (CW) stains and KOH mounts were found in 97.3% (286/294) and 76.5% (225/294), respectively (p < 0.05). Of the cases diagnosed by microscopy and culture, fungi were isolated in 152 (51.7%), with Fusarium spp. being the most frequently identified (n = 69, 45.5%) followed by dematiaceous fungi (n = 45, 29.6%) and Aspergillus spp. (n = 18, 11.8%). The incidence of FK was higher in the rainy season of July to October. The mean age was 54.4 ± 14.4 (SD) years, with a range of 9–88 years. Males (75.8%) were affected significantly more than females (24.2%) (p < 0.05). Of 294 patients, 132 (44.9%) were middle-aged adults (41–60 years) and 107 (36.4%) were older than 60 years. Trauma to the eye by soil or vegetative matter were the most common preceding factors (188/294; 64.0%). We assessed two virulence factors. First, 142 of the 152 culture-positive FK cases were due to molds, indicating that hyphal morphogenesis is extremely important in disease. We also demonstrated that fungal melanization occurs in the molds during the course of FK by applying a melanin-specific monoclonal antibody (MAb) that labeled fungal elements in corneal samples of patients, and melanin particles derived from the hyphae were also recovered after treatment of the samples with proteolytic enzymes, denaturant and hot concentrated acid. In summary, we demonstrate that northern Thailand has a high rate of FK that is influenced by season and males engaged in outside activities are at highest risk for disease. Moulds are significantly more commonly responsible for FK, in part due to their capacity to form hyphae and melanins. Future studies will examine models of fungal corneal interactions and assess additional factors of virulence, such as secreted enzymes, to more deeply decipher the pathogenesis of FK.
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Liu S, Youngchim S, Zamith-Miranda D, Nosanchuk JD. Fungal Melanin and the Mammalian Immune System. J Fungi (Basel) 2021; 7:jof7040264. [PMID: 33807336 PMCID: PMC8066723 DOI: 10.3390/jof7040264] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/25/2021] [Accepted: 03/26/2021] [Indexed: 02/06/2023] Open
Abstract
Melanins are ubiquitous complex polymers that are commonly known in humans to cause pigmentation of our skin. Melanins are also present in bacteria, fungi, and helminths. In this review, we will describe the diverse interactions of fungal melanin with the mammalian immune system. We will particularly focus on Cryptococcus neoformans and also discuss other major melanotic pathogenic fungi. Melanin interacts with the immune system through diverse pathways, reducing the effectiveness of phagocytic cells, binding effector molecules and antifungals, and modifying complement and antibody responses.
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Affiliation(s)
- Sichen Liu
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (S.L.); (D.Z.-M.)
| | - Sirida Youngchim
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand;
| | - Daniel Zamith-Miranda
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (S.L.); (D.Z.-M.)
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Joshua D. Nosanchuk
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (S.L.); (D.Z.-M.)
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Correspondence:
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Bhattacharya S, Bouklas T, Fries BC. Replicative Aging in Pathogenic Fungi. J Fungi (Basel) 2020; 7:6. [PMID: 33375605 PMCID: PMC7824483 DOI: 10.3390/jof7010006] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/16/2020] [Accepted: 12/23/2020] [Indexed: 12/14/2022] Open
Abstract
Candida albicans, Candida auris, Candida glabrata, and Cryptococcus neoformans are pathogenic yeasts which can cause systemic infections in immune-compromised as well as immune-competent individuals. These yeasts undergo replicative aging analogous to a process first described in the nonpathogenic yeast Saccharomyces cerevisiae. The hallmark of replicative aging is the asymmetric cell division of mother yeast cells that leads to the production of a phenotypically distinct daughter cell. Several techniques to study aging that have been pioneered in S. cerevisiae have been adapted to study aging in other pathogenic yeasts. The studies indicate that aging is relevant for virulence in pathogenic fungi. As the mother yeast cell progressively ages, every ensuing asymmetric cell division leads to striking phenotypic changes, which results in increased antifungal and antiphagocytic resistance. This review summarizes the various techniques that are used to study replicative aging in pathogenic fungi along with their limitations. Additionally, the review summarizes some key phenotypic variations that have been identified and are associated with changes in virulence or resistance and thus promote persistence of older cells.
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Affiliation(s)
- Somanon Bhattacharya
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; (T.B.); (B.C.F.)
| | - Tejas Bouklas
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; (T.B.); (B.C.F.)
- Department of Biological Sciences, State University of New York College at Old Westbury, Old Westbury, NY 11568, USA
| | - Bettina C. Fries
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; (T.B.); (B.C.F.)
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY 11794, USA
- Veterans Administration Medical Center, Northport, NY 11768, USA
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He X, Liu D, Chen Q. Proteomic analysis on the regulation of DOPA-melanin synthesis in Talaromyces marneffei. Microb Pathog 2020; 150:104701. [PMID: 33340654 DOI: 10.1016/j.micpath.2020.104701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 11/17/2020] [Accepted: 12/06/2020] [Indexed: 11/26/2022]
Abstract
BACKGROUND Yeast form of T.marneffei can produce DOPA-melanin which perform an important role in the pathogen surviving in macrophage. So far, the proteomic associated with melanin synthesis remain unclearly in T.marneffei. METHODS The whole yeast cell proteins were extracted from T.marneffei cultured with or without l-DOPA. Using two-dimensional gel electrophoresis combined with MALDI-TOF mass spectrometry, distinguished proteins were identified between T.marneffei cultured with or without l-DOPA. Furthermore, geldanamycin were used to assess the inhibition effect on T.marneffei melanin production in vitro. RESULTS 16 distinguished proteins were identified in DOPA-melanized yeast cells, as well as 15 triple-up-expressed proteins and 7 triple-down-expressed proteins in comparison with non DOPA-melanized yeast cells. Of note, proteins differentially expressed proteins were predominantly heat shock proteins. HSP90/60/70 genes expressions increased significantly demonstrated by q-RT-PCR, which was consistent with the proteomics changes. GO analysis showed that the majority of differentially expressed proteins including HSPs(especially HSP90) were found enriched in stress response, cellular process, protein folding, stimuli response and biological process. KEGG pathway analysis showed that proteins were enriched predominantly in phagosome. HSP90 inhibitor(Geldanamycin) inhibited the brown-black pigment production of T.marneffei yeast grown on brain heart infusion agar, as well as the inhibition effect was observed by transmission electron microscope. CONCLUSIONS The results demonstrates that HSP90 palys an essential role in T.marneffei DOPA-melanin synthesis pathway.
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Affiliation(s)
- Xiaoyue He
- Department of Dermatology and Venereology, First Affiliated Hospital,Guangxi Medical University, Nanning, Guangxi, 530021, China
| | - Donghua Liu
- Department of Dermatology and Venereology, First Affiliated Hospital,Guangxi Medical University, Nanning, Guangxi, 530021, China; Guangxi Key Laboratory of AIDS Prevention and Treatment,Nanning, Guangxi, 530021, China.
| | - Qicong Chen
- Institutes for Life Sciences School of Medicine South China University of Technology Guangzhou, Guangzhou, Guangdong, 510515, China
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Sangkanu S, Rukachaisirikul V, Suriyachadkun C, Phongpaichit S. Antifungal activity of marine-derived actinomycetes against Talaromyces marneffei. J Appl Microbiol 2020; 130:1508-1522. [PMID: 33010096 DOI: 10.1111/jam.14877] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/11/2020] [Accepted: 09/24/2020] [Indexed: 01/27/2023]
Abstract
AIMS This study aimed to isolate actinomycetes from marine environments and examine their antifungal activity against Talaromyces marneffei both in vitro and in vivo. METHODS AND RESULTS Nineteen out of 101 actinomycete extracts were active and further determined for their minimum inhibitory concentrations (MIC). Three extracts of AMA50 that isolated from sediment showed strong antifungal activity against T. marneffei yeast (MICs ≤0·03-0·25 µg ml-1 ) and mould (MICs 0·5-16 µg ml-1 ) forms. The hexane extract from the cells of AMA50 (AMA50CH) exhibited the best activity against both the forms (MIC ≤ 1 µg ml-1 ). Three extracts from AMA50 killed the melanized yeast cells at 0·5 µg ml-1 . The AMA50CH was further tested for protective effects in Caenorhabditis elegans model. At concentrations of 1-8 µg ml-1 , the AMA50CH prolonged survival of T. marneffei-infected C. elegans with a 60-70% survival rate. The composition of AMA50CH was determined by gas chromatography-mass spectrometry. The major components were n-hexadecanoic acid, tetradecanoic acid and pentadecanoic acid. Sequencing analysis revealed that isolate AMA50 belonged to the genus Streptomyces. CONCLUSIONS The AMA50CH from Streptomyces sp. AMA50 was the most effective extract against T. marneffei. SIGNIFICANCE AND IMPACT OF THE STUDY Talaromyces marneffei is one of the most important thermally dimorphic pathogenic fungi. These results indicated the potency of marine-derived actinomycete extracts against T. marneffei both in vitro and in vivo.
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Affiliation(s)
- S Sangkanu
- Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - V Rukachaisirikul
- Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - C Suriyachadkun
- BIOTEC Culture Collection, Biodiversity and Biotechnological Resource Research Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Khlong Luang, Pathum Thani, Thailand
| | - S Phongpaichit
- Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand.,Natural Product Research Center of Excellence, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand.,Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
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Chongkae S, Nosanchuk JD, Pruksaphon K, Laliam A, Pornsuwan S, Youngchim S. Production of melanin pigments in saprophytic fungi in vitro and during infection. J Basic Microbiol 2019; 59:1092-1104. [PMID: 31613011 DOI: 10.1002/jobm.201900295] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/31/2019] [Accepted: 08/09/2019] [Indexed: 01/08/2023]
Abstract
Melanins are one of the great natural pigments produced by a wide variety of fungal species that promote fitness and cell survival in diverse hostile environments, including during mammalian infection. In this study, we sought to demonstrate the production of melanin in the conidia and hyphae of saprophytic fungi, including dematiaceous and hyaline fungi. We showed that a melanin-specific monoclonal antibody (MAb) avidly labeled the cell walls of hyphae and conidia, consistent with the presence of melanin in these structures, in 14 diverse fungal species. The conidia of saprophytic fungi were treated with proteolytic enzymes, denaturant, and concentrated hot acid to yield dark particles, which were shown to be stable free radicals, consistent with their identification as melanins. Samples obtained from patients with fungal keratitis due to Fusarium falciforme, Aspergillus fumigatus, Aspergillus flavus, Curvularia lunata, Exserohilum rostratum, or Fonsecaea pedrosoi were found to be intensely labeled by the melanin-specific MAb at the fungal hyphal cell walls. These results support the hypothesis that melanin is a common component that promotes survival under harsh conditions and facilitates fungal virulence. Increased understanding of the processes of melanization and the development of methods to interfere with pigment formation may lead to novel approaches to combat these complex pathogens that are associated with high rates of morbidity and mortality.
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Affiliation(s)
- Siriporn Chongkae
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Joshua D Nosanchuk
- Department of Medicine (Infectious Diseases), Albert Einstein College of Medicine, Bronx
| | - Kritsada Pruksaphon
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Angkana Laliam
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Soraya Pornsuwan
- Department of Chemistry, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Sirida Youngchim
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
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Tsang CC, Lau SKP, Woo PCY. Sixty Years from Segretain’s Description: What Have We Learned and Should Learn About the Basic Mycology of Talaromyces marneffei? Mycopathologia 2019; 184:721-729. [DOI: 10.1007/s11046-019-00395-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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14
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The Role of Melanin in Fungal Pathogenesis for Animal Hosts. Curr Top Microbiol Immunol 2019; 422:1-30. [PMID: 31278515 DOI: 10.1007/82_2019_173] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Melanins are a class of pigments that are ubiquitous throughout biology. They play incredibly diverse and important roles ranging from radiation protection to immune defense, camouflage, and virulence. Fungi have evolved to use melanin to be able to persist in the environment and within organisms. Fungal melanins are often located within the cell well and are able to neutralize reactive oxygen species and other radicals, defend against UV radiation, bind and sequester non-specific peptides and compounds, and produce a physical barrier that defends the cell. For this reason, melanized fungi are often well-suited to be human pathogens-melanin allows fungi to neutralize the microbicidal oxidative bursts of our innate immune system, bind and inactivate to antimicrobial peptides and enzymes, sequester antifungal pharmaceuticals, and create a shield to block immune recognition of the fungus. Due to the importance and pervasiveness of melanin in fungal virulence, mammalian immune systems have evolved antifungal strategies that involve directly detecting and binding to fungal melanins. Such strategies include the use of melanin-specific antibody responses and C-type lectins like the newly discovered melanin-specific MelLec receptor.
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Raman NM, Ramasamy S. Genetic validation and spectroscopic detailing of DHN-melanin extracted from an environmental fungus. Biochem Biophys Rep 2017; 12:98-107. [PMID: 28955797 PMCID: PMC5613234 DOI: 10.1016/j.bbrep.2017.08.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 07/27/2017] [Accepted: 08/17/2017] [Indexed: 11/30/2022] Open
Abstract
Accurate characterization of melanin using analytical methodologies has proved to be difficult due to its heterogeneity, insolubility in wide pH and broad range of solvents. The present study was undertaken to characterize melanin extracted from an environmental Aspergillus fumigatus AFGRD105 by studying its genes, chemical properties and spectral data. A gene based approach to confirm the type of melanin carried out indicated the extracted melanin to be of the dihydroxynaphthalene type. On comparison with synthetic melanin, UV–Vis and IR spectra of the extracted melanin revealed characteristic peaks that can be further used for confirmation of DHN-melanin extracted from any source. Solid state 13C NMR spectroscopy established the presence of the hydroxyl-naphthalene moiety and validated the results obtained by genetic analysis. The correct assignment of the observed spectral frequency characteristic of functional groups can be further adapted in future works that deal with binding capacities and biomolecule systems involving melanin. DNA was extracted by a standardised protocol that can be adapted for environmental and clinically isolated fungi. The presence of genes was used to identify the type of melanin. Physico chemical characterization of the melanin extracted was performed. UV–Vis and IR spectra were used to confirm the type of melanin. Further, the chemical moieties were substantiated using 13C solid state NMR spectroscopy.
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Affiliation(s)
- Nitya Meenakshi Raman
- Department of Biotechnology, Dr. G. R. Damodaran College of Science, Bharathiar University, Coimbatore 641014, India
| | - Suganthi Ramasamy
- Department of Biotechnology, Dr. G. R. Damodaran College of Science, Bharathiar University, Coimbatore 641014, India
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16
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Adaptation to macrophage killing by Talaromyces marneffei. Future Sci OA 2017; 3:FSO215. [PMID: 28884011 PMCID: PMC5583664 DOI: 10.4155/fsoa-2017-0032] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 05/03/2017] [Indexed: 01/09/2023] Open
Abstract
Talaromyces (Penicillium) marneffei is an important opportunistic fungal pathogen. It causes disseminated infection in immunocompromised patients especially in Southeast Asian countries. The pathogenicity of T. marneffei depends on the ability of the fungus to survive the killing process and replicate inside the macrophage. Major stresses inside the phagosome of macrophages are heat, oxidative substances and nutrient deprivation. The coping strategies of this pathogen with these stresses are under investigation. This paper summarizes factors relating to the stress responses that contribute to the intracellular survival of T. marneffei. These include molecules in the MAP signal transduction cascade, heat shock proteins, antioxidant enzymes and enzymes responsible in nutrient retrieval. There is speculation that the ability of T. marneffei to withstand these defenses plays an important role in its pathogenicity. Talaromyces marneffei is an important dimorphic fungus that causes disease in immunocompromised patients. The pathogenicity of T. marneffei depends on the ability of the fungus to survive the killing process and replicate inside the host macrophage cells. This paper summarizes factors relating to the stress responses that contribute to the intracellular survival of T. marneffei. There is speculation that the ability of T. marneffei to withstand these defenses plays an important role in its pathogenicity.
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17
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Chiewchanvit S, Chongkae S, Mahanupab P, Nosanchuk JD, Pornsuwan S, Vanittanakom N, Youngchim S. Melanization of Fusarium keratoplasticum (F. solani Species Complex) During Disseminated Fusariosis in a Patient with Acute Leukemia. Mycopathologia 2017; 182:879-885. [PMID: 28616680 DOI: 10.1007/s11046-017-0156-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Accepted: 06/06/2017] [Indexed: 12/22/2022]
Abstract
Fusarium spp. are recognized as the second most frequently filamentous fungi causing opportunistic infections and particularly important due to the increasing number of immunocompromised patients. F. keratoplasticum (a member of F. solani species complex) is one of the Fusarium species commonly associated with human infection, and therefore, studies on the virulence of this fungus are needed. This study aimed to confirm the presence of melanin in F. keratoplasticum from a patient with systemic fusariosis. Immunofluorescence labeling with anti-melanin monoclonal antibody (MAb) was used to examine an expression of melanin in F. keratoplasticum in vitro and during infection. Electron spin resonance identified the particles extracted from F. keratoplasticum as stable free radical consistent with melanin. Lesional skin from the sites with fusariosis contained hyphal structures that could be labeled by melanin-binding MAb, while digestion of the tissue yielded dark particles that were reactive. These findings suggest that F. keratoplasticum hyphae and chlamydospores can produce melanin in vitro and that hyphae can synthesize pigment in vivo. Given the potential role of melanin in virulence of other fungi, this pigment in F. keratoplasticum may play a role in the pathogenesis of fusariosis.
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Affiliation(s)
- Siri Chiewchanvit
- Department of Internal Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Siriporn Chongkae
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Pongsak Mahanupab
- Department of Pathology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Joshua D Nosanchuk
- Department of Medicine (Infectious Diseases), Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Soraya Pornsuwan
- Department of Physical Chemistry, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Nongnuch Vanittanakom
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Sirida Youngchim
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.
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18
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Williamson PR. Role of laccase in the virulence of Talaromyces marneffei: A common link between AIDS-related fungal pathogens? Virulence 2016; 7:627-9. [PMID: 27282335 DOI: 10.1080/21505594.2016.1198867] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Peter R Williamson
- a Laboratory of Clinical Infectious Diseases , National Institute of Allergy and Infectious Diseases, National Institutes of Health , Bethesda , MD , USA
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19
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Sapmak A, Kaewmalakul J, Nosanchuk JD, Vanittanakom N, Andrianopoulos A, Pruksaphon K, Youngchim S. Talaromyces marneffei laccase modifies THP-1 macrophage responses. Virulence 2016; 7:702-17. [PMID: 27224737 DOI: 10.1080/21505594.2016.1193275] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Talaromyces (Penicillium) marneffei is an emerging opportunistic pathogen associated with HIV infection, particularly in Southeast Asia and southern China. The rapid uptake and killing of T. marneffei conidia by phagocytic cells along with the effective induction of an inflammatory response by the host is essential for disease control. T. marneffei produces a number of different laccases linked to fungal virulence. To understand the role of the various laccases in T. marneffei, laccase-encoding genes were investigated. Targeted single, double and triple gene deletions of laccases encoding lacA, lacB, and lacC showed no significant phenotypic effects suggesting redundancy of function. When a fourth laccase-encoding gene, pbrB, was deleted in the ΔlacA ΔlacB ΔlacC background, the quadruple mutant displayed delayed conidiation and the conidia were more sensitive to H2O2, sodium dodecyl sulfate (SDS), and antifungal agents than wild-type and other transformants. Conidia of the quadruple mutant showed marked differences in their interaction with the human monocyte cell line, THP-1 such that phagocytosis was significantly higher when compared with the wild-type at one and 2 hours of incubation while the phagocytic index was significantly different from 15 to 120 minutes. In addition, killing of the quadruple mutant by THP-1 cells was more efficient at 2 and 4 hours of incubation. The levels of the proinflammatory cytokines TNF-α, IL-1β and IL-6 from THP-1 cells infected with the quadruple mutant were also significantly increased in comparison with wild-type. The results demonstrate that production of laccases by T. marneffei actually promotes the pathogen's resistance to innate host defenses.
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Affiliation(s)
- Ariya Sapmak
- a Department of Microbiology , Faculty of Medicine, Chiang Mai University , Chiang Mai , Thailand.,b Faculty of Medical Technology, Nakhon Ratchasima College , Nakhon Ratchasima , Thailand
| | - Jutikul Kaewmalakul
- a Department of Microbiology , Faculty of Medicine, Chiang Mai University , Chiang Mai , Thailand
| | - Joshua D Nosanchuk
- c Department of Medicine, Division of Infectious Diseases, and Department of Microbiology and Immunology , Albert Einstein College of Medicine , Bronx , NY , USA
| | - Nongnuch Vanittanakom
- a Department of Microbiology , Faculty of Medicine, Chiang Mai University , Chiang Mai , Thailand
| | - Alex Andrianopoulos
- d Genetics, Genomics and Development, School of BioSciences, The University of Melbourne , Victoria , Australia
| | - Kritsada Pruksaphon
- a Department of Microbiology , Faculty of Medicine, Chiang Mai University , Chiang Mai , Thailand
| | - Sirida Youngchim
- a Department of Microbiology , Faculty of Medicine, Chiang Mai University , Chiang Mai , Thailand
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20
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Almeida-Paes R, Figueiredo-Carvalho MHG, Brito-Santos F, Almeida-Silva F, Oliveira MME, Zancopé-Oliveira RM. Melanins Protect Sporothrix brasiliensis and Sporothrix schenckii from the Antifungal Effects of Terbinafine. PLoS One 2016; 11:e0152796. [PMID: 27031728 PMCID: PMC4816517 DOI: 10.1371/journal.pone.0152796] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/18/2016] [Indexed: 01/18/2023] Open
Abstract
Terbinafine is a recommended therapeutic alternative for patients with sporotrichosis who cannot use itraconazole due to drug interactions or side effects. Melanins are involved in resistance to antifungal drugs and Sporothrix species produce three different types of melanin. Therefore, in this study we evaluated whether Sporothrix melanins impact the efficacy of antifungal drugs. Minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) of two Sporothrix brasiliensis and four Sporothrix schenckii strains grown in the presence of the melanin precursors L-DOPA and L-tyrosine were similar to the MIC determined by the CLSI standard protocol for S. schenckii susceptibility to amphotericin B, ketoconazole, itraconazole or terbinafine. When MICs were determined in the presence of inhibitors to three pathways of melanin synthesis, we observed, in four strains, an increase in terbinafine susceptibility in the presence of tricyclazole, a DHN-melanin inhibitor. In addition, one S. schenckii strain grown in the presence of L-DOPA had a higher MFC value when compared to the control. Growth curves in presence of 2×MIC concentrations of terbinafine showed that pyomelanin and, to a lesser extent, eumelanin were able to protect the fungi against the fungicidal effect of this antifungal drug. Our results suggest that melanin protects the major pathogenic species of the Sporothrix complex from the effects of terbinafine and that the development of new antifungal drugs targeting melanin synthesis may improve sporotrichosis therapies.
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Affiliation(s)
- Rodrigo Almeida-Paes
- Laboratório de Micologia, Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
- * E-mail:
| | | | - Fábio Brito-Santos
- Laboratório de Micologia, Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Fernando Almeida-Silva
- Laboratório de Micologia, Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | | | - Rosely Maria Zancopé-Oliveira
- Laboratório de Micologia, Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
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21
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Prakit K, Nosanchuk JD, Pruksaphon K, Vanittanakom N, Youngchim S. A novel inhibition ELISA for the detection and monitoring of Penicillium marneffei antigen in human serum. Eur J Clin Microbiol Infect Dis 2016; 35:647-56. [PMID: 26838686 DOI: 10.1007/s10096-016-2583-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 01/11/2016] [Indexed: 11/28/2022]
Abstract
The thermally dimorphic fungus Penicillium marneffei is a causative agent of penicilliosis marneffei, a disease considered to be an acquired immune deficiency syndrome (AIDS)-defining illness in Southeast Asia and southern China. We have developed an inhibition enzyme-linked immunosorbent assay (inh-ELISA) incorporating the yeast phase specific mannoprotein-binding monoclonal antibody 4D1 for the detection of P. marneffei infection. In our sample set, the test detected antigenemia in all 45 (100 %) patients with P. marneffei, with a mean antigen concentration of 4.32 μg/ml. No cross-reactivity in this assay was found using serum from 44 additional patients with other fungal infections, such as Aspergillus fumigatus, Cryptococcus neoformans, and Candida albicans, as well as 44 patients with bacterial infections, such as Mycobacterium tuberculosis and Streptococcus suis. Additionally, no reactivity occurred using serum from 31 human immunodeficiency virus (HIV)-infected patients without a history of fungal infections and 113 healthy controls residing in endemic areas. To investigate the potential of the inh-ELISA for disease monitoring, we followed the reduction in antigenemia in six patients who clinically responded to itraconazole and P. marneffei was no longer isolated from their blood or tissues. In contrast, we correlated increased concentrations of antigenemia in patients with relapsed P. marneffei infection with the progression of their clinical symptoms and the isolation of P. marneffei from their clinical specimens. In summary, the P. marneffei inh-ELISA is a promising new assay for the rapid diagnosis of P. marneffei, as well as a tool for evaluating clinical response and clearance of the fungus during treatment.
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Affiliation(s)
- K Prakit
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - J D Nosanchuk
- Departments of Medicine (Infectious Diseases) and Microbiology/Immunology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - K Pruksaphon
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - N Vanittanakom
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - S Youngchim
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.
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22
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Tam EWT, Tsang CC, Lau SKP, Woo PCY. Polyketides, toxins and pigments in Penicillium marneffei. Toxins (Basel) 2015; 7:4421-36. [PMID: 26529013 PMCID: PMC4663511 DOI: 10.3390/toxins7114421] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 09/18/2015] [Accepted: 10/22/2015] [Indexed: 11/17/2022] Open
Abstract
Penicillium marneffei (synonym: Talaromyces marneffei) is the most important pathogenic thermally dimorphic fungus in China and Southeastern Asia. The HIV/AIDS pandemic, particularly in China and other Southeast Asian countries, has led to the emergence of P. marneffei infection as an important AIDS-defining condition. Recently, we published the genome sequence of P. marneffei. In the P. marneffei genome, 23 polyketide synthase genes and two polyketide synthase-non-ribosomal peptide synthase hybrid genes were identified. This number is much higher than those of Coccidioides immitis and Histoplasma capsulatum, important pathogenic thermally dimorphic fungi in the Western world. Phylogenetically, these polyketide synthase genes were distributed evenly with their counterparts found in Aspergillus species and other fungi, suggesting that polyketide synthases in P. marneffei did not diverge from lineage-specific gene duplication through a recent expansion. Gene knockdown experiments and ultra-high performance liquid chromatography-photodiode array detector/electrospray ionization-quadruple time of flight-mass spectrometry analysis confirmed that at least four of the polyketide synthase genes were involved in the biosynthesis of various pigments in P. marneffei, including melanin, mitorubrinic acid, mitorubrinol, monascorubrin, rubropunctatin, citrinin and ankaflavin, some of which were mycotoxins and virulence factors of the fungus.
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Affiliation(s)
- Emily W T Tam
- Department of Microbiology, The University of Hong Kong, Pokfulam, Hong Kong.
| | - Chi-Ching Tsang
- Department of Microbiology, The University of Hong Kong, Pokfulam, Hong Kong.
| | - Susanna K P Lau
- Department of Microbiology, The University of Hong Kong, Pokfulam, Hong Kong.
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Pokfulam, Hong Kong.
- Research Centre of Infection and Immunology, The University of Hong Kong, Pokfulam, Hong Kong.
- Carol Yu Centre for Infection, The University of Hong Kong, Pokfulam, Hong Kong.
| | - Patrick C Y Woo
- Department of Microbiology, The University of Hong Kong, Pokfulam, Hong Kong.
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Pokfulam, Hong Kong.
- Research Centre of Infection and Immunology, The University of Hong Kong, Pokfulam, Hong Kong.
- Carol Yu Centre for Infection, The University of Hong Kong, Pokfulam, Hong Kong.
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23
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Sapmak A, Boyce KJ, Andrianopoulos A, Vanittanakom N. The pbrB gene encodes a laccase required for DHN-melanin synthesis in conidia of Talaromyces (Penicillium) marneffei. PLoS One 2015; 10:e0122728. [PMID: 25866870 PMCID: PMC4395095 DOI: 10.1371/journal.pone.0122728] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 02/15/2015] [Indexed: 11/19/2022] Open
Abstract
Talaromyces marneffei (Basionym: Penicillium marneffei) is a significant opportunistic fungal pathogen in patients infected with human immunodeficiency virus in Southeast Asia. T. marneffei cells have been shown to become melanized in vivo. Melanins are pigment biopolymers which act as a non-specific protectant against various stressors and which play an important role during virulence in fungi. The synthesis of the two most commonly found melanins in fungi, the eumelanin DOPA-melanin and the allomelanin DHN-melanin, requires the action of laccase enzymes. The T. marneffei genome encodes a number of laccases and this study describes the characterization of one of these, pbrB, during growth and development. A strain carrying a PbrB-GFP fusion shows that pbrB is expressed at high levels during asexual development (conidiation) but not in cells growing vegetatively. The pbrB gene is required for the synthesis of DHN-melanin in conidia and when deleted results in brown pigmented conidia, in contrast to the green conidia of the wild type.
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Affiliation(s)
- Ariya Sapmak
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Kylie J Boyce
- Department of Genetics, Faculty of Science, University of Melbourne, Victoria, Australia
| | - Alex Andrianopoulos
- Department of Genetics, Faculty of Science, University of Melbourne, Victoria, Australia
| | - Nongnuch Vanittanakom
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
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24
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Boyce KJ, McLauchlan A, Schreider L, Andrianopoulos A. Intracellular growth is dependent on tyrosine catabolism in the dimorphic fungal pathogen Penicillium marneffei. PLoS Pathog 2015; 11:e1004790. [PMID: 25812137 PMCID: PMC4374905 DOI: 10.1371/journal.ppat.1004790] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 03/06/2015] [Indexed: 12/21/2022] Open
Abstract
During infection, pathogens must utilise the available nutrient sources in order to grow while simultaneously evading or tolerating the host’s defence systems. Amino acids are an important nutritional source for pathogenic fungi and can be assimilated from host proteins to provide both carbon and nitrogen. The hpdA gene of the dimorphic fungus Penicillium marneffei, which encodes an enzyme which catalyses the second step of tyrosine catabolism, was identified as up-regulated in pathogenic yeast cells. As well as enabling the fungus to acquire carbon and nitrogen, tyrosine is also a precursor in the formation of two types of protective melanin; DOPA melanin and pyomelanin. Chemical inhibition of HpdA in P. marneffei inhibits ex vivo yeast cell production suggesting that tyrosine is a key nutrient source during infectious growth. The genes required for tyrosine catabolism, including hpdA, are located in a gene cluster and the expression of these genes is induced in the presence of tyrosine. A gene (hmgR) encoding a Zn(II)2-Cys6 binuclear cluster transcription factor is present within the cluster and is required for tyrosine induced expression and repression in the presence of a preferred nitrogen source. AreA, the GATA-type transcription factor which regulates the global response to limiting nitrogen conditions negatively regulates expression of cluster genes in the absence of tyrosine and is required for nitrogen metabolite repression. Deletion of the tyrosine catabolic genes in the cluster affects growth on tyrosine as either a nitrogen or carbon source and affects pyomelanin, but not DOPA melanin, production. In contrast to other genes of the tyrosine catabolic cluster, deletion of hpdA results in no growth within macrophages. This suggests that the ability to catabolise tyrosine is not required for macrophage infection and that HpdA has an additional novel role to that of tyrosine catabolism and pyomelanin production during growth in host cells. Fungi that infect humans are a major health problem, especially for those with compromised immune systems. Many fungal infections are extremely difficult to cure and if left untreated are fatal. For successful infection to occur, the fungal pathogen must be able to grow by acquiring and utilising the available nutrient sources within the host whilst evading or tolerating the host’s defence systems. Expression profiling in several pathogenic fungal species has revealed that genes required for tyrosine catabolism are induced specifically in the pathogenic cell type at 37°C. As well as enabling the fungus to acquire carbon and nitrogen intermediates from proteins within the host, tyrosine is also an important precursor in the formation of two different types of melanin, which protects cells against the host’s defence systems. This study shows that the ability to catabolise tyrosine and produce tyrosine derived melanin is not required for the initial stages of fungal infection. However, a novel role for hpdA, which encodes the enzyme which catalyses the second step of tyrosine catabolism, was identified during growth in host cells.
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Affiliation(s)
- Kylie J. Boyce
- School of BioSciences, The University of Melbourne, Parkville, Australia
- * E-mail:
| | - Alisha McLauchlan
- South Australian Clinical Genetics Service, SA Pathology, Adelaide, Australia
| | - Lena Schreider
- School of BioSciences, The University of Melbourne, Parkville, Australia
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25
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Pal AK, Gajjar DU, Vasavada AR. DOPA and DHN pathway orchestrate melanin synthesis in Aspergillus species. Med Mycol 2014; 52:10-8. [PMID: 23998343 DOI: 10.3109/13693786.2013.826879] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Melanins are high molecular weight hydrophobic pigments that have been studied for their role in the virulence of fungal pathogens. We investigated the amount and type of melanin in 20 isolates of Aspergillus spp.; A. niger (n = 3), A. flavus (n = 5), A. tamarii (n = 3), A. terreus (n = 3), A. tubingensis (n = 3), A. sydowii (n = 3). Aspergillus spp. were identified by sequencing the internal transcribed spacer (ITS) region. Extraction of melanin from culture filtrate and fungal biomass was done and followed by qualitative and quantitative analysis of melanin pigment. Ultraviolet (UV), Fourier transformed infrared (FT-IR), and electron paramagnetic resonance (EPR) spectra analyses confirmed the presence of melanin. The melanin pathway was studied by analyzing the effects of inhibitors; kojic acid, tropolone, phthalide, and tricyclazole. The results indicate that in A. niger and A. tubingensis melanin was found in both culture filtrate and fungal biomass. For A. tamarii and A. flavus melanin was extracted from biomass only, whereas melanin was found only in culture filtrate for A. terreus. A negligible amount of melanin was found in A. sydowii. The maximum amount of melanin from culture filtrate and fungal biomass was found in A. niger and A. tamarrii, respectively. The DOPA (3,4-dihydroxyphenylalanine) pathway produces melanin in A. niger, A. tamarii and A. flavus, whereas the DHN (1,8-dihydroxynaphthalene) pathway produces melanin in A. tubingensis and A. terreus. It can be concluded that the amount and type of melanin in aspergilli largely differ from species to species.
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Affiliation(s)
- Anuradha K Pal
- Iladevi Cataract and IOL Research Centre, Ahmedabad, Gujarat
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26
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Kaewmalakul J, Nosanchuk JD, Vanittanakom N, Youngchim S. Melanization and morphological effects on antifungal susceptibility of Penicillium marneffei. Antonie Van Leeuwenhoek 2014; 106:1011-20. [PMID: 25227777 PMCID: PMC4194899 DOI: 10.1007/s10482-014-0270-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 08/25/2014] [Indexed: 11/25/2022]
Abstract
The biosynthesis of melanin has been linked with virulence in diverse pathogenic fungi. Penicillium marneffei, a dimorphic fungus, is capable of melanization in both mycelial and yeast phases, and the pigment may be produced during infection to protect the fungus from the host immune system. To investigate the impact of yeast morphological transformation on antifungal susceptibility, P. marneffei was cultured on various media including minimal medium, 1 % tryptone, brain heart infusion broth, and malt extract broth by using the standardized susceptibility protocol (the M27-A protocol, RPMI medium) for yeasts. We also investigated whether P. marneffei melanization affected its susceptibility to antifungal drugs by adding L-DOPA into culture broths. There were no differences in the minimum inhibitory concentrations of P. marneffei yeast cells previously grown in various culture broths with or without L-DOPA using the M27A protocol (into which no melanin substrate can be added due to a rapid colour change of the RPMI medium to black) for testing amphotericin B, clotrimazole, fluconazole, itraconazole and ketoconazole. However, both melanized and non-melanized P. marneffei displayed increased resistance to antifungal drugs when L-DOPA was added into a selected assay medium, 0.17 % yeast nitrogen base, 2 % glucose, and 1.5 % agar. Hence, active melanin formation appears to protect P. marneffei by enhancing its resistance to antifungal drugs.
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Affiliation(s)
- Jutikul Kaewmalakul
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
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27
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Liu D, Wei L, Guo T, Tan W. Detection of DOPA-melanin in the dimorphic fungal pathogen Penicillium marneffei and its effect on macrophage phagocytosis in vitro. PLoS One 2014; 9:e92610. [PMID: 24647795 PMCID: PMC3960263 DOI: 10.1371/journal.pone.0092610] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 02/24/2014] [Indexed: 02/05/2023] Open
Abstract
The fungal pathogen Penicillium marneffei produces melanin-like pigment in vitro. The synthetic pathway of melanin and its possible influence in the protective yeast cells surviving within macrophage cells are not known. In this work, P. marneffei produced brown black pigment in the presence of L-DOPA and black particles were extracted from yeast cells treated with proteolytic enzymes, denaturant and concentrated hot acid. Kojic acid inhibited the brown-black pigment production of P. marneffei yeast grown on brain heart infusion agar. Transmitting electron microscopy showed spherical granular electron-dense particles with an average diameter of 100 nm in a beaded arrangement in the innermost cell wall. Electron-paramagnetic resonance revealed that the black particles contain a stable free radical compound. The UV-visible and Fourier transform infrared spectra of particles extracted from P. marneffei and synthetic DOPA-melanin showed a high degree of similarity. Melanized yeast cells decreased phagocytosis by macrophage cells and increased resistance to intracellular digestion in vitro. These results indicate that P. marneffei can synthesize DOPA-melanin or melanin-like compounds in vitro and suggest that the DOPA-melanin pathway is associated with cell wall structure and enhances the resistance to phagocytosis by macrophages.
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Affiliation(s)
- Donghua Liu
- Department of Dermatology and Venereology, First Affiliated Hospital, Guangxi Medical University, Nanning, China
- * E-mail:
| | - Lili Wei
- Department of Dermatology and Venereology, First Affiliated Hospital, Guangxi Medical University, Nanning, China
| | - Ting Guo
- Department of Dermatology and Venereology, First Affiliated Hospital, Guangxi Medical University, Nanning, China
| | - Weifen Tan
- Department of Dermatology and Venereology, First Affiliated Hospital, Guangxi Medical University, Nanning, China
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Youngchim S, Nosanchuk JD, Pornsuwan S, Kajiwara S, Vanittanakom N. The role of L-DOPA on melanization and mycelial production in Malassezia furfur. PLoS One 2013; 8:e63764. [PMID: 23762233 PMCID: PMC3676409 DOI: 10.1371/journal.pone.0063764] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Accepted: 04/05/2013] [Indexed: 11/18/2022] Open
Abstract
Melanins are synthesized by organisms of all biological kingdoms and comprise a heterogeneous class of natural pigments. Certain of these polymers have been implicated in the pathogenesis of several important human fungal pathogens. This study investigated whether the fungal skin pathogen Malassezia furfur produces melanin or melanin-like compounds. A melanin-binding monoclonal antibody (MAb) labelled in vitro cultivated yeast cells of M. furfur. In addition, melanization of Malassezia yeasts and hyphae was detected by anti-melanin MAb in scrapings from patients with pityriasis versicolor. Treatment of Malassezia yeasts with proteolytic enzymes, denaturant and concentrated hot acid yielded dark particles and electron spin resonance spectroscopy revealed that these particles contained a stable free radical compound, consistent with their identification as melanins. Malassezia yeasts required phenolic compounds, such as L-DOPA, in order to synthesize melanin. L-DOPA also triggered hyphal formation in vitro when combined with kojic acid, a tyrosinase inhibitor, in a dose-dependent manner. In this respect, L-DOPA is thought to be an essential substance that is linked to both melanization and yeast-mycelial transformation in M. furfur. In summary, M. furfur can produce melanin or melanin-like compounds in vitro and in vivo, and the DOPA melanin pathway is involved in cell wall melanization.
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Affiliation(s)
- Sirida Youngchim
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
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29
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Lin X, Ran Y, Gou L, He F, Zhang R, Wang P, Dai Y. Comprehensive transcription analysis of human pathogenic fungus Penicillium marneffei in mycelial and yeast cells. Med Mycol 2012; 50:835-42. [PMID: 22563855 DOI: 10.3109/13693786.2012.678398] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Penicillium marneffei is a dimorphic fungus that responds to changes in temperature. We performed a comparative analysis of gene expression in mycelial- and yeast-phase P. marneffei cells using high-throughput DNA microarrays. A total of 1,884 differentially expressed genes with annotations in the gene ontology (GO) database were identified between P. marneffei mycelial and yeast cells. These differentially expressed genes mainly belong to 18 categories in the organism's ontology, including reproduction, immunity, metabolism, signaling, etc. Bioinformatics suggests that these differentially expressed genes may help explain the resistance to adverse environments and the virulence of P. marneffei. Nine genes from the results of the DNA microarray experiment were selected for further analysis with real-time quantitative PCR to validate the differential expression. Our data provide a global description of the transcriptional response accompanying adaptation to high temperature in yeast.
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Affiliation(s)
- Xinyu Lin
- Department of Dermatology, West China Hospital, Sichuan University, Chengdu, China
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30
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Urán ME, Nosanchuk JD, Restrepo A, Hamilton AJ, Gómez BL, Cano LE. Detection of antibodies against Paracoccidioides brasiliensis melanin in in vitro and in vivo studies during infection. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2011; 18:1680-8. [PMID: 21813659 PMCID: PMC3187017 DOI: 10.1128/cvi.05099-11] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Accepted: 07/26/2011] [Indexed: 12/18/2022]
Abstract
Several cell wall constituents, including melanins or melanin-like compounds, have been implicated in the pathogenesis of a wide variety of microbial diseases caused by diverse species of pathogenic bacteria, fungi, and helminthes. Among these microorganisms, the dimorphic fungal pathogen Paracoccidioides brasiliensis produces melanin in its conidial and yeast forms. In the present study, melanin particles from P. brasiliensis were injected into BALB/c mice in order to produce monoclonal antibodies (MAbs). We identified five immunoglobulin G1 (IgG1) κ-chain and four IgM melanin-binding MAbs. The five IgG1 κ-chain isotypes are the first melanin-binding IgG MAbs ever reported. The nine MAbs labeled P. brasiliensis conidia and yeast cells both in vitro and in pulmonary tissues. The MAbs cross-reacted with melanin-like purified particles from other fungi and also with commercial melanins, such as synthetic and Sepia officinalis melanin. Melanization during paracoccidioidomycosis (PCM) was also further supported by the detection of IgG antibodies reactive to melanin from P. brasiliensis conidia and yeast in sera and bronchoalveolar lavage fluids from P. brasiliensis-infected mice, as well as in sera from human patients with PCM. Serum specimens from patients with other mycoses were also tested for melanin-binding antibodies by enzyme-linked immunosorbent assay, and cross-reactivities were detected for melanin particles from different fungal sources. These results suggest that melanin from P. brasiliensis is an immunologically active fungal structure that activates a strong IgG humoral response in humans and mice.
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Affiliation(s)
- Martha E Urán
- Medical and Experimental Mycology Unit, Corporación para Investigaciones Biológicas, Carrera 72A No. 78B-141, A.A. 73-78, Medellín, Colombia.
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Kumar CG, Mongolla P, Pombala S, Kamle A, Joseph J. Physicochemical characterization and antioxidant activity of melanin from a novel strain of Aspergillus bridgeri ICTF-201. Lett Appl Microbiol 2011; 53:350-8. [DOI: 10.1111/j.1472-765x.2011.03116.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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32
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Youngchim S, Pornsuwan S, Nosanchuk JD, Dankai W, Vanittanakom N. Melanogenesis in dermatophyte species in vitro and during infection. MICROBIOLOGY-SGM 2011; 157:2348-2356. [PMID: 21565930 DOI: 10.1099/mic.0.047928-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Dermatophytes are keratinophilic fungi that are the most common cause of fungal skin infections worldwide. Melanin has been isolated from several important human fungal pathogens, and the polymeric pigment is now recognized as an important virulence determinant. This study investigated whether dermatophytes, including Trichophyton rubrum, Trichophyton mentagrophytes, Epidermophyton floccosum and Microsporum gypseum, produce melanin or melanin-like compounds in vitro and during infection. Digestion of the pigmented microconidia and macroconidia of dermatophytes with proteolytic enzymes, denaturant and hot concentrated acid yielded dark particles that retained the size and shape of the original fungal cells. Electron spin resonance spectroscopy revealed that particles derived from pigmented conidia contained a stable free radical signal, consistent with the pigments being a melanin. Immunofluorescence analysis demonstrated reactivity of a melanin-binding mAb with the pigmented conidia and hyphae, as well as the isolate particles. Laccase, an enzyme involved in melanization, was detected in the dermatophytes by an agar plate assay using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as the substrate. Skin scrapings from patients with dermatophytoses contained septate hyphae and arthrospores that were reactive with the melanin-binding mAb. These findings indicate that dermatophytes can produce melanin or melanin-like compounds in vitro and during infection. Based on what is known about the function of melanin as a virulence factor of other pathogenic fungi, this pigment may have a similar role in the pathogenesis of dermatophytic diseases.
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Affiliation(s)
- Sirida Youngchim
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Thailand
| | - Soraya Pornsuwan
- Department of Physical Chemistry, Faculty of Science, Mahidol University, Thailand
| | - Joshua D Nosanchuk
- Department of Medicine (Infectious Diseases), Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Wiyada Dankai
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Thailand
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Woo PCY, Tam EWT, Chong KTK, Cai JJ, Tung ETK, Ngan AHY, Lau SKP, Yuen KY. High diversity of polyketide synthase genes and the melanin biosynthesis gene cluster in Penicillium marneffei. FEBS J 2010; 277:3750-8. [DOI: 10.1111/j.1742-4658.2010.07776.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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34
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Loussert C, Schmitt C, Prevost MC, Balloy V, Fadel E, Philippe B, Kauffmann-Lacroix C, Latgé JP, Beauvais A. In vivo biofilm composition of Aspergillus fumigatus. Cell Microbiol 2009; 12:405-10. [PMID: 19889082 DOI: 10.1111/j.1462-5822.2009.01409.x] [Citation(s) in RCA: 189] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The in vivo composition of the mycelial extracellular matrix (ECM) of Aspergillus fumigatus during host invasion is reported here for the first time. A new galactosaminogalactan and the galactomannan were the major polysaccharides of the in vivo ECM. The composition of the ECM in vivo varied with the aspergillosis pathologies.
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Affiliation(s)
- Céline Loussert
- Electron Microscopy Platform, Institut Pasteur, Paris, France
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35
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Ultrastructural characterization of melanosomes of the human pathogenic fungus Fonsecaea pedrosoi. J Struct Biol 2008; 162:75-84. [DOI: 10.1016/j.jsb.2007.11.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2007] [Revised: 10/26/2007] [Accepted: 11/09/2007] [Indexed: 11/22/2022]
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36
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Cooper CR, Vanittanakom N. Insights into the pathogenicity of Penicillium marneffei. Future Microbiol 2008; 3:43-55. [PMID: 18230033 DOI: 10.2217/17460913.3.1.43] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Penicillium marneffei is a significant pathogen of AIDS patients in Southeast Asia. This fungus is unique in that it is the only dimorphic member of the genus. Pathogenesis of P. marneffei requires the saprobic mold form to undergo a morphological change upon tissue invasion. The in vivo form of this fungus reproduces as a fission yeast that capably evades the host immune system. The processes that control these morphological changes, better termed as phase transition, can be replicated in vitro by incubation of the mold form at 37 degrees C. The unidentified molecular mechanisms regulating phase transition in this fungus are now being uncovered using modern methodologies and novel strategies. A better comprehension of these underlying regulatory pathways will provide insight into eukaryotic cellular development as well as the potential factors responsible for infections caused by P. marneffei and other fungi. Such knowledge may lead to better chemotherapeutic interventions of fungal diseases.
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Affiliation(s)
- Chester R Cooper
- Department of Biological Sciences, Youngstown State University, 1 University Plaza, Youngstown, OH 44555, USA.
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Abstract
Tropical mycoses vary from the commonplace to the rare and exotic but they are seen regularly even as imported conditions and it is important to consider the diagnosis, where possible, in individuals who have visited remote areas. Patients may present many years after they have left an endemic area with subcutaneous or endemic systemic mycoses. In establishing a diagnosis, it is always important to take an accurate travel history so that the movements of the individual can be correlated with the potential risk for exposure to infection.
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Affiliation(s)
- Roderick J Hay
- Faculty of Medicine and Health Sciences, Queens University Belfast, Northern Ireland, UK.
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Dijksterhuis J, Nijsse J, Hoekstra FA, Golovina EA. High viscosity and anisotropy characterize the cytoplasm of fungal dormant stress-resistant spores. EUKARYOTIC CELL 2006; 6:157-70. [PMID: 17099083 PMCID: PMC1797940 DOI: 10.1128/ec.00247-06] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Ascospores of the fungus Talaromyces macrosporus are dormant and extremely stress resistant, whereas fungal conidia--the main airborne vehicles of distribution--are not. Here, physical parameters of the cytoplasm of these types of spores were compared. Cytoplasmic viscosity and level of anisotropy as judged by spin probe studies (electron spin resonance) were extremely high in dormant ascospores and during early germination and decreased only partly after trehalose degradation and glucose efflux. Upon prosilition (ejection of the spore), these parameters fell sharply to values characteristic of vegetative cells. These changes occurred without major volume changes that suggest dramatic changes in cytoplasmic organization. Azide reversibly inhibited prosilition as well as the decline in cytoplasmic parameters. No organelle structures were observed in etched, cryoplaned specimens of ascospores by low-temperature scanning electron microscopy (LTSEM), confirming the high cytoplasmic viscosity. However, cell structures became visible upon prosilition, indicating reduced viscosity. The viscosity of fresh conidia of different Penicillium species was lower, namely, 3.5 to 4.8 cP, than that of ascospores, near 15 cP. In addition the level of anisotropic motion was markedly lower in these cells (h(0)/h(+1) = 1.16 versus 1.4). This was confirmed by LTSEM images showing cell structures. The decline of cytoplasmic viscosity in conidia during germination was linked with a gradual increase in cell volume. These data show that mechanisms of cytoplasm conservation during germination differ markedly between ascospores and conidia.
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Affiliation(s)
- J Dijksterhuis
- Department of Applied and Industrial Mycology, Centraalbureau voor Schimmelcultures, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands.
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Moon JL, Shaw LN, Mayo JA, Potempa J, Travis J. Isolation and properties of extracellular proteinases of Penicillium marneffei. Biol Chem 2006; 387:985-93. [PMID: 16913848 DOI: 10.1515/bc.2006.122] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Penicillium marneffei is a dimorphic fungus native to Southeast Asia. Disease caused by this organism, until recently a very rare condition, has increased dramatically in parallel with the increase in the number of individuals in the region immunocompromised by AIDS and other conditions. While much research has been performed on the control of dimorphic switching in P. marneffei, there is a relative dearth of information regarding the proteinases secreted by this pathogen. Our laboratory has purified and characterized two proteinases produced by this organism in liquid culture and cloned the gene of a third. Both the recombinant enzyme expressed from the cloned gene and one of those purified from culture supernatants have been identified as members of the eqolisin family, a group of pepstatin-insensitive acid proteinases. The other enzyme purified from a culture supernatant is a serine proteinase with activity in the neutral pH range. These enzymes appear to be differentially expressed, depending on culture conditions.
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Affiliation(s)
- Jonathan L Moon
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602-7229, USA
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