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Alonso-Monge R, Cortés-Prieto I, Román E, Pla J. Morphogenetic transitions in the adaptation of Candida albicans to the mammalian gut. Microbes Infect 2024; 26:105253. [PMID: 37977323 DOI: 10.1016/j.micinf.2023.105253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 11/06/2023] [Accepted: 11/12/2023] [Indexed: 11/19/2023]
Abstract
Candida albicans is a pathobiont in humans that forms part of the mycobiota in healthy individuals and can cause different pathologies upon alterations of the host defenses. The mammalian gut is clinically relevant as this niche is the most common pool for bloodstream-derived infections. The ability of C. albicans to switch from yeast to hypha has been related to the commensal-to-pathogen transition and is, therefore, considered relevant in virulence. Recently, filaments have been implicated in the humoral response in the gut. C. albicans exhibits other morphologies that play different roles in pathogenicity and commensalism. This review focuses on the role of these morphological transitions in C. albicans proliferation and its establishment as a commensal in the mammalian gut, paying special attention to the transcription factors involved in their regulation.
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Affiliation(s)
- Rebeca Alonso-Monge
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain.
| | - Isabel Cortés-Prieto
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain.
| | - Elvira Román
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain.
| | - Jesús Pla
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain.
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2
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Wu H, Wang L, Wang W, Shao Z, Jia X, Xiao H, Chen J. The secretory Candida effector Sce1 licenses fungal virulence by masking the immunogenic β-1,3-glucan and promoting apoptosis of the host cells. MLIFE 2023; 2:159-177. [PMID: 38817625 PMCID: PMC10989805 DOI: 10.1002/mlf2.12066] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 03/28/2023] [Accepted: 04/05/2023] [Indexed: 06/01/2024]
Abstract
Candida albicans deploys a variety of mechanisms such as morphological switch and elicitor release to promote virulence. However, the intricate interactions between the fungus and the host remain poorly understood, and a comprehensive inventory of fungal virulence factors has yet to be established. In this study, we identified a C. albicans secretory effector protein Sce1, whose induction and secretion are associated with vagina-simulative conditions and chlamydospore formation. Sequence alignment showed that Sce1 belongs to a Pir family in C. albicans, which is conserved across several fungi and primarily characterized as a β-glucan binding protein in the Saccharomyces cerevisiae. Mechanically, Sce1 is primarily localized to the cell wall in a cleaved form as an alkali-labile β-1,3-glucan binding protein and plays a role in masking β-glucan in acidic environments and chlamydospores, a feature that might underline C. albicans' ability to evade host immunity. Further, a cleaved short form of Sce1 protein could be released into extracellular compartments and presented in bone marrow-derived macrophages infected with chlamydospores. This cleaved short form of Sce1 also demonstrated a unique ability to trigger the caspases-8/9-dependent apoptosis in various host cells. Correspondingly, genetic deletion of SCE1 led to dampened vaginal colonization of C. albicans and diminished fungal virulence during systemic infection. The discovery of Sce1 as a versatile virulence effector that executes at various compartments sheds light on the fungus-host interactions and C. albicans pathogenesis.
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Affiliation(s)
- Hongyu Wu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghaiChina
| | - Li Wang
- The Center for Microbes, Development and Health, Institut Pasteur of Shanghai, Chinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghaiChina
- Clinical Medicine Scientific and Technical Innovation Center, Shanghai Tenth People's HospitalTongji University School of MedicineShanghaiChina
| | - Wenjuan Wang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghaiChina
| | - Zhugui Shao
- The Center for Microbes, Development and Health, Institut Pasteur of Shanghai, Chinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghaiChina
- Key Laboratory of Infection and Immunity of Shandong Province and Department of Immunology, School of Biomedical SciencesShandong UniversityJinanChina
| | - Xin‐Ming Jia
- Clinical Medicine Scientific and Technical Innovation Center, Shanghai Tenth People's HospitalTongji University School of MedicineShanghaiChina
| | - Hui Xiao
- The Center for Microbes, Development and Health, Institut Pasteur of Shanghai, Chinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghaiChina
| | - Jiangye Chen
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghaiChina
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Williams S, Cleary I, Thomas D. Anaerobic conditions are a major influence on Candida albicans chlamydospore formation. Folia Microbiol (Praha) 2022; 68:321-324. [PMID: 36418845 DOI: 10.1007/s12223-022-01018-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 11/13/2022] [Indexed: 11/25/2022]
Abstract
Candidiasis now represents the fourth most frequent nosocomial infection both in the USA and worldwide. Candida albicans is an increasingly common threat to human health as a consequence of AIDS, steroid therapy, organ and tissue transplantation, cancer therapy, broad-spectrum antibiotics, and other immune defects. Unfortunately, these infections carry unacceptably high morbidity, mortality rates and important economic repercussions (estimated total direct cost of approximately 2 billion dollars in 1998 in US hospitals alone). This pathogen can grow both in yeast and filamentous forms and the pathogenic potential of C. albicans is intimately related to certain key processes including filamentation. Chlamydospores are considered to be a dormant form of C. albicans that remain understudied. Chlamydospores have been widely used as a diagnostic tool to separate C. albicans and C. dubliniensis from other Candida species. More recently, media have been developed that use chlamydopsore formation to separate C. albicans and C. dubliniensis from each other. Chlamydospore formation can be stimulated by hypoxic conditions but only on limited specific media types. Here, we show that anaerobic conditions are enough to drive chlamydospore formation in C. albicans on the surface of nutrient-rich agar.
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Affiliation(s)
- Shannon Williams
- Department of Biomedical Sciences, Grand Valley State University, 1 Campus Drive, Allendale, MI, 49401-9401, USA
| | - Ian Cleary
- Department of Biomedical Sciences, Grand Valley State University, 1 Campus Drive, Allendale, MI, 49401-9401, USA
| | - Derek Thomas
- Department of Biomedical Sciences, Grand Valley State University, 1 Campus Drive, Allendale, MI, 49401-9401, USA.
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Bacterial hitchhikers derive benefits from fungal housing. Curr Biol 2022; 32:1523-1533.e6. [PMID: 35235767 PMCID: PMC9009100 DOI: 10.1016/j.cub.2022.02.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 10/14/2021] [Accepted: 02/03/2022] [Indexed: 12/21/2022]
Abstract
Fungi and bacteria are ubiquitous constituents of all microbiomes, yet mechanisms of microbial persistence in polymicrobial communities remain obscure. Here, we examined the hypothesis that specialized fungal survival structures, chlamydospores, induced by bacterial lipopeptides serve as bacterial reservoirs. We find that symbiotic and pathogenic gram-negative bacteria from non-endosymbiotic taxa enter and propagate in chlamydospores. Internalized bacteria have higher fitness than planktonic bacteria when challenged with abiotic stress. Further, tri-cultures of Ralstonia solanacearum, Pseudomonas aeruginosa, and Aspergillus flavus reveal the unprecedented finding that chlamydospores are colonized by endofungal bacterial communities. Our work identifies a previously unknown ecological role of chlamydospores, provides an expanded view of microbial niches, and presents significant implications for the persistence of pathogenic and beneficial bacteria.
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A conserved regulator controls asexual sporulation in the fungal pathogen Candida albicans. Nat Commun 2020; 11:6224. [PMID: 33277479 PMCID: PMC7718266 DOI: 10.1038/s41467-020-20010-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 11/03/2020] [Indexed: 12/16/2022] Open
Abstract
Transcription factor Rme1 is conserved among ascomycetes and regulates meiosis and pseudohyphal growth in Saccharomyces cerevisiae. The genome of the meiosis-defective pathogen Candida albicans encodes an Rme1 homolog that is part of a transcriptional circuitry controlling hyphal growth. Here, we use chromatin immunoprecipitation and genome-wide expression analyses to study a possible role of Rme1 in C. albicans morphogenesis. We find that Rme1 binds upstream and activates the expression of genes that are upregulated during chlamydosporulation, an asexual process leading to formation of large, spherical, thick-walled cells during nutrient starvation. RME1 deletion abolishes chlamydosporulation in three Candida species, whereas its overexpression bypasses the requirement for chlamydosporulation cues and regulators. RME1 expression levels correlate with chlamydosporulation efficiency across clinical isolates. Interestingly, RME1 displays a biphasic pattern of expression, with a first phase independent of Rme1 function and dependent on chlamydospore-inducing cues, and a second phase dependent on Rme1 function and independent of chlamydospore-inducing cues. Our results indicate that Rme1 plays a central role in chlamydospore development in Candida species.
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Román E, Correia I, Prieto D, Alonso R, Pla J. The HOG MAPK pathway in Candida albicans: more than an osmosensing pathway. Int Microbiol 2019; 23:23-29. [DOI: 10.1007/s10123-019-00069-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 02/21/2019] [Accepted: 02/27/2019] [Indexed: 12/18/2022]
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Verrucous Plaque With Unusually Large Candida Blastoconidia: A Unique Clinicopathological Presentation of Systemic Mucocutaneous Candidiasis. Am J Dermatopathol 2018; 40:846-848. [PMID: 29672362 DOI: 10.1097/dad.0000000000001153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Mucocutaneous candidiasis is a common infection affecting both immunocompetent and immunosuppressed individuals. Diversity in the clinical and histopathological presentation of mucocutaneous candidiasis is well known. However, the occurrence of cutaneous verrucous lesions and giant yeast-like structures has been rarely reported. In this article, we describe a case of disseminated mucocutaneous candidiasis in an immunosuppressed patient who presented as a verrucous plaque on the scrotum with giant Candida blastoconidia. This peculiar presentation expands the clinicopathological spectrum of mucocutaneous candidiasis and highlights the wide range of clinical manifestations and great morphologic variability of this common fungal infection.
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Sun ZB, Zhang J, Sun MH, Li SD. Identification of genes related to chlamydospore formation in Clonostachys rosea 67-1. Microbiologyopen 2018; 8:e00624. [PMID: 29635882 PMCID: PMC6341034 DOI: 10.1002/mbo3.624] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 02/11/2018] [Accepted: 02/16/2018] [Indexed: 01/15/2023] Open
Abstract
Chlamydospores are specific structures that are of great significance to the commercialization of fungal biopesticides. To explore the genes associated with chlamydospore formation, a biocontrol fungus Clonostachys rosea 67‐1 that is capable of producing resistant spores under particular conditions was investigated by transcriptome sequencing and analysis. A total of 549,661,174 clean reads were obtained, and a series of differentially expressed genes potentially involved in fungal chlamydospore formation were identified. At 36 hr, 67 and 117 genes were up‐ and downregulated in C. rosea during chlamydospore production, compared with the control for conidiation, and 53 and 24 genes were up‐ and downregulated at 72 hr. GO classification suggested that the differentially expressed genes were related to cellular component, biological process, and molecular function categories. A total of 188 metabolism pathways were linked to chlamydospore production by KEGG analysis. Sixteen differentially expressed genes were verified by reverse transcription quantitative PCR, and the expression profiles were consistent with the transcriptome data. To the best of our knowledge, it is the first report on the genes associated with chlamydospore formation in C. rosea. The results provide insight into the molecular mechanisms underlying C. rosea sporulation, which will assist the development of fungal biocontrol agents.
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Affiliation(s)
- Zhan-Bin Sun
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jun Zhang
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Man-Hong Sun
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shi-Dong Li
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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Giosa D, Felice MR, Lawrence TJ, Gulati M, Scordino F, Giuffrè L, Lo Passo C, D'Alessandro E, Criseo G, Ardell DH, Hernday AD, Nobile CJ, Romeo O. Whole RNA-Sequencing and Transcriptome Assembly of Candida albicans and Candida africana under Chlamydospore-Inducing Conditions. Genome Biol Evol 2017; 9:1971-1977. [PMID: 28810711 PMCID: PMC5553385 DOI: 10.1093/gbe/evx143] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/25/2017] [Indexed: 12/27/2022] Open
Abstract
Candida albicans is the most common cause of life-threatening fungal infections in humans, especially in immunocompromised individuals. Crucial to its success as an opportunistic pathogen is the considerable dynamism of its genome, which readily undergoes genetic changes generating new phenotypes and shaping the evolution of new strains. Candida africana is an intriguing C. albicans biovariant strain that exhibits remarkable genetic and phenotypic differences when compared with standard C. albicans isolates. Candida africana is well-known for its low degree of virulence compared with C. albicans and for its inability to produce chlamydospores that C. albicans, characteristically, produces under certain environmental conditions. Chlamydospores are large, spherical structures, whose biological function is still unknown. For this reason, we have sequenced, assembled, and annotated the whole transcriptomes obtained from an efficient C. albicans chlamydospore-producing clinical strain (GE1), compared with the natural chlamydospore-negative C. africana clinical strain (CBS 11016). The transcriptomes of both C. albicans (GE1) and C. africana (CBS 11016) clinical strains, grown under chlamydospore-inducing conditions, were sequenced and assembled into 7,442 (GE1 strain) and 8,370 (CBS 11016 strain) high quality transcripts, respectively. The release of the first assembly of the C. africana transcriptome will allow future comparative studies to better understand the biology and evolution of this important human fungal pathogen.
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Affiliation(s)
| | - Maria Rosa Felice
- Department of Chemical, Biological, Pharmaceutical, and Environmental Sciences, University of Messina, Italy
| | - Travis J Lawrence
- Department of Molecular and Cell Biology, University of California, Merced, CA.,Quantitative and System Biology Graduate Program, University of California, Merced, CA
| | - Megha Gulati
- Department of Molecular and Cell Biology, University of California, Merced, CA
| | | | - Letterio Giuffrè
- Department of Veterinary Sciences, Division of Animal Production, University of Messina, Italy
| | - Carla Lo Passo
- Department of Chemical, Biological, Pharmaceutical, and Environmental Sciences, University of Messina, Italy
| | - Enrico D'Alessandro
- Department of Veterinary Sciences, Division of Animal Production, University of Messina, Italy
| | - Giuseppe Criseo
- Department of Chemical, Biological, Pharmaceutical, and Environmental Sciences, University of Messina, Italy
| | - David H Ardell
- Department of Molecular and Cell Biology, University of California, Merced, CA
| | - Aaron D Hernday
- Department of Molecular and Cell Biology, University of California, Merced, CA
| | - Clarissa J Nobile
- Department of Molecular and Cell Biology, University of California, Merced, CA
| | - Orazio Romeo
- IRCCS Centro Neurolesi "Bonino-Pulejo," Messina, Italy.,Department of Chemical, Biological, Pharmaceutical, and Environmental Sciences, University of Messina, Italy
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Noble SM, Gianetti BA, Witchley JN. Candida albicans cell-type switching and functional plasticity in the mammalian host. Nat Rev Microbiol 2016; 15:96-108. [PMID: 27867199 DOI: 10.1038/nrmicro.2016.157] [Citation(s) in RCA: 315] [Impact Index Per Article: 39.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Candida albicans is a ubiquitous commensal of the mammalian microbiome and the most prevalent fungal pathogen of humans. A cell-type transition between yeast and hyphal morphologies in C. albicans was thought to underlie much of the variation in virulence observed in different host tissues. However, novel yeast-like cell morphotypes, including opaque(a/α), grey and gastrointestinally induced transition (GUT) cell types, were recently reported that exhibit marked differences in vitro and in animal models of commensalism and disease. In this Review, we explore the characteristics of the classic cell types - yeast, hyphae, pseudohyphae and chlamydospores - as well as the newly identified yeast-like morphotypes. We highlight emerging knowledge about the associations of these different morphotypes with different host niches and virulence potential, as well as the environmental cues and signalling pathways that are involved in the morphological transitions.
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Affiliation(s)
- Suzanne M Noble
- Department of Microbiology and Immunology, University of California San Francisco (UCSF) School of Medicine.,Infectious Diseases Division, Department of Medicine, University of California San Francisco (UCSF) School of Medicine, San Francisco, California 94143, USA
| | - Brittany A Gianetti
- Department of Microbiology and Immunology, University of California San Francisco (UCSF) School of Medicine
| | - Jessica N Witchley
- Department of Microbiology and Immunology, University of California San Francisco (UCSF) School of Medicine
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Navarathna DHMLP, Pathirana RU, Lionakis MS, Nickerson KW, Roberts DD. Candida albicans ISW2 Regulates Chlamydospore Suspensor Cell Formation and Virulence In Vivo in a Mouse Model of Disseminated Candidiasis. PLoS One 2016; 11:e0164449. [PMID: 27727302 PMCID: PMC5058487 DOI: 10.1371/journal.pone.0164449] [Citation(s) in RCA: 13] [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: 01/20/2016] [Accepted: 09/26/2016] [Indexed: 01/05/2023] Open
Abstract
Formation of chlamydospores by Candida albicans was an established medical diagnostic test to confirm candidiasis before the molecular era. However, the functional role and pathological relevance of this in vitro morphological transition to pathogenesis in vivo remain unclear. We compared the physical properties of in vitro-induced chlamydospores with those of large C. albicans cells purified by density gradient centrifugation from Candida-infected mouse kidneys. The morphological and physical properties of these cells in kidneys of mice infected intravenously with wild type C. albicans confirmed that chlamydospores can form in infected kidneys. A previously reported chlamydospore-null Δisw2/Δisw2 mutant was used to investigate its role in virulence and chlamydospore induction. Virulence of the Δisw2/Δisw2 mutant strain was reduced 3.4-fold compared to wild type C. albicans or the ISW2 reconstituted strain. Altered host inflammatory reactions to the null mutant further indicate that ISW2 is a virulence factor in C. albicans. ISW2 deletion abolished chlamydospore formation within infected mouse kidneys, whereas the reconstituted strain restored chlamydospore formation in kidneys. Under chlamydospore inducing conditions in vitro, deletion of ISW2 significantly delayed chlamydospore formation, and those late induced chlamydospores lacked associated suspensor cells while attaching laterally to hyphae via novel spore-hypha septa. Our findings establish the induction of chlamydospores by C. albicans during mouse kidney colonization. Our results indicate that ISW2 is not strictly required for chlamydospores formation but is necessary for suspensor cell formation. The importance of ISW2 in chlamydospore morphogenesis and virulence may lead to additional insights into morphological differentiation and pathogenesis of C. albicans in the host microenvironment.
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Affiliation(s)
- Dhammika H. M. L. P. Navarathna
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ruvini U. Pathirana
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Michail S. Lionakis
- Fungal Pathogenesis Unit, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Kenneth W. Nickerson
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - David D. Roberts
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
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12
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Palige K, Linde J, Martin R, Böttcher B, Citiulo F, Sullivan DJ, Weber J, Staib C, Rupp S, Hube B, Morschhäuser J, Staib P. Global transcriptome sequencing identifies chlamydospore specific markers in Candida albicans and Candida dubliniensis. PLoS One 2013; 8:e61940. [PMID: 23613980 PMCID: PMC3626690 DOI: 10.1371/journal.pone.0061940] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 03/07/2013] [Indexed: 11/29/2022] Open
Abstract
Candida albicans and Candida dubliniensis are pathogenic fungi that are highly related but differ in virulence and in some phenotypic traits. During in vitro growth on certain nutrient-poor media, C. albicans and C. dubliniensis are the only yeast species which are able to produce chlamydospores, large thick-walled cells of unknown function. Interestingly, only C. dubliniensis forms pseudohyphae with abundant chlamydospores when grown on Staib medium, while C. albicans grows exclusively as a budding yeast. In order to further our understanding of chlamydospore development and assembly, we compared the global transcriptional profile of both species during growth in liquid Staib medium by RNA sequencing. We also included a C. albicans mutant in our study which lacks the morphogenetic transcriptional repressor Nrg1. This strain, which is characterized by its constitutive pseudohyphal growth, specifically produces masses of chlamydospores in Staib medium, similar to C. dubliniensis. This comparative approach identified a set of putatively chlamydospore-related genes. Two of the homologous C. albicans and C. dubliniensis genes (CSP1 and CSP2) which were most strongly upregulated during chlamydospore development were analysed in more detail. By use of the green fluorescent protein as a reporter, the encoded putative cell wall related proteins were found to exclusively localize to C. albicans and C. dubliniensis chlamydospores. Our findings uncover the first chlamydospore specific markers in Candida species and provide novel insights in the complex morphogenetic development of these important fungal pathogens.
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Affiliation(s)
- Katja Palige
- Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Junior Research Group Fundamental Molecular Biology of Pathogenic Fungi, Jena, Germany
| | - Jörg Linde
- Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Systems Biology/Bioinformatics, Jena, Germany
| | - Ronny Martin
- Center for Innovation Competence Septomics, Research Group Fungal Septomics at the Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Bettina Böttcher
- Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Junior Research Group Fundamental Molecular Biology of Pathogenic Fungi, Jena, Germany
| | - Francesco Citiulo
- Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Molecular Pathogenicity Mechanisms, Jena, Germany
- School of Dental Science and Dublin Dental University Hospital, Trinity College Dublin, University of Dublin, Dublin, Ireland
| | - Derek J. Sullivan
- School of Dental Science and Dublin Dental University Hospital, Trinity College Dublin, University of Dublin, Dublin, Ireland
| | - Johann Weber
- Lausanne Genomic Technologies Facility, Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Claudia Staib
- Department of Obstetrics and Gynecology, University of Würzburg, Würzburg, Germany
| | - Steffen Rupp
- Fraunhofer Institute for Interfacial Engineering and Biotechnology, Stuttgart, Germany
| | - Bernhard Hube
- Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Molecular Pathogenicity Mechanisms, Jena, Germany
- Friedrich Schiller University, Jena, Germany
- Center for Sepsis Control and Care, Jena University Hospital, Jena, Germany
| | - Joachim Morschhäuser
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Peter Staib
- Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Junior Research Group Fundamental Molecular Biology of Pathogenic Fungi, Jena, Germany
- Department of Research and Development, Kneipp-Werke, Würzburg, Germany
- * E-mail:
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13
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Candida albicans biofilms formed into catheters and probes and their resistance to amphotericin B. J Mycol Med 2011; 21:182-7. [DOI: 10.1016/j.mycmed.2011.07.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 07/06/2011] [Indexed: 11/17/2022]
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Abstract
Many of the major human fungal pathogens are known to undergo morphological changes, which in certain cases are associated with virulence. Although there has been an intense research focus on morphology in fungi, very little is known about how morphology evolved in conjunction with a variety of other virulence properties. However, several recent important discoveries, primarily in Candida species, are beginning to shed light on this important area and answer many longstanding questions. In this minireview, we first provide a description of the major fungal morphologies, as well as the roles of morphology and morphology-associated gene expression in virulence. Next, focusing largely on Candida species, we examine the evolutionary relationships among specific morphological forms. Finally, drawing on recent findings, we begin to address the question of how specific morphological changes came to be associated with virulence of Candida species during evolution.
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15
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Citiulo F, Moran GP, Coleman DC, Sullivan DJ. Purification and germination of Candida albicans and Candida dubliniensis chlamydospores cultured in liquid media. FEMS Yeast Res 2009; 9:1051-60. [PMID: 19538507 DOI: 10.1111/j.1567-1364.2009.00533.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Candida albicans and Candida dubliniensis are the only Candida sp. that have been observed to produce chlamydospores. The function of these large, thick-walled cells is currently unknown. In this report, we describe the production and purification of chlamydospores from these species in defined liquid media. Staining with the fluorescent dye FUN-1 indicated that chlamydospores are metabolically active cells, but that metabolic activity is undetectable in chlamydospores that are >30 days old. However, 5-15-day-old chlamydospores could be induced to produce daughter chlamydospores, blastospores, pseudohyphae and true hyphae depending on the incubation conditions used. Chlamydospores that were preinduced to germinate were also observed to escape from murine macrophages following phagocytosis, suggesting that these structures may be viable in vivo. Mycelium-attached and purified chlamydospores rapidly lost their viability in water and when subjected to dry stress, suggesting that they are unlikely to act as long-term storage structures. Instead, our data suggest that chlamydospores represent an alternative specialized form of growth by C. albicans and C. dubliniensis.
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Affiliation(s)
- Francesco Citiulo
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental School and Hospital, Trinity College Dublin, University of Dublin, Dublin 2, Ireland
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Román E, Arana DM, Nombela C, Alonso-Monge R, Pla J. MAP kinase pathways as regulators of fungal virulence. Trends Microbiol 2007; 15:181-90. [PMID: 17321137 DOI: 10.1016/j.tim.2007.02.001] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2006] [Revised: 01/30/2007] [Accepted: 02/08/2007] [Indexed: 11/15/2022]
Abstract
MAP kinases are dual phosphorylated protein kinases, present in eukaryotes, which mediate differentiation programs and immune responses in mammalian cells. In pathogenic fungi, MAP kinases are key elements that control adaptation to environmental stress. Recent studies have shown that these pathways have an essential role in the control of essential virulence factors such as capsule biogenesis in Cryptococcus neoformans or morphogenesis, invasion and oxidative stress in Candida albicans. Although MAP kinases sense different activating signals, there is a considerable degree of crosstalk and/or overlap, which enables them to integrate, amplify and modulate the appropriate protective and adaptive response. MAP kinases behave as a 'functional nervous system' that controls virulence and influences the progression of the disease.
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Affiliation(s)
- Elvira Román
- Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza de Ramón y Cajal s/n, E-28040 Madrid, Spain
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17
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Staib P, Morschhäuser J. Chlamydospore formation in Candida albicans and Candida dubliniensis? an enigmatic developmental programme. Mycoses 2007; 50:1-12. [PMID: 17302741 DOI: 10.1111/j.1439-0507.2006.01308.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Chlamydospore formation has served for a long time for identification of the human fungal pathogen Candida albicans, but the biological function of these structures still remains a secret. They have been proposed to allow survival in harsh environmental conditions, but this assumption remains to be proven. Chlamydospores are produced only by the two closely related species C. albicans and Candida dubliniensis, whose natural habitats are humans and warm-blooded animals, but not by other Candida species that are also found outside animal hosts. However, no role in the pathogenesis of Candida infections has been assigned to these unusual cells and only a limited number of studies have been conducted in the past to unravel their function. The development of new molecular tools and the recent discovery of mating in C. albicans have also restimulated investigations to understand the morphogenesis and function of chlamydospores. The finding that chlamydospore formation is differentially controlled by certain environmental signals in C. albicans and C. dubliniensis has opened new approaches to study the regulation of this morphogenetic programme. These studies have already identified genes and signalling pathways that are required for chlamydospore production and should lead to a detailed understanding of this fascinating developmental process.
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Affiliation(s)
- Peter Staib
- Institut für Molekulare Infektionsbiologie, Universität Würzburg, Röntgenring, Würzburg, Germany
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18
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F.Vellucci V, Gygax S, Hostetter MK. Involvement of Candida albicans pyruvate dehydrogenase complex protein X (Pdx1) in filamentation. Fungal Genet Biol 2006; 44:979-90. [PMID: 17254815 PMCID: PMC2062515 DOI: 10.1016/j.fgb.2006.12.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2006] [Revised: 12/05/2006] [Accepted: 12/06/2006] [Indexed: 11/29/2022]
Abstract
For 50 years, physiologic studies in Candida albicans have associated fermentation with filamentation and respiration with yeast morphology. Analysis of the mitochondrial proteome of a C. albicans NDH51 mutant, known to be defective in filamentation, identified increased expression of several proteins in the respiratory pathway. Most notable was a 15-fold increase in pyruvate dehydrogenase complex protein X (Pdx1), an essential component of the pyruvate dehydrogenase complex. In basal salts medium with < or = 100 mM glucose as carbon source, two independent pdx1 mutants displayed a filamentation defect identical to ndh51; reintegration of one PDX1 allele restored filamentation. Concentrations of glucose < or = 100 mM did not correct the filamentation defect. Expanding on previous work, these studies suggest that increased expression of proteins extraneous to the electron transport chain compensates for defects in the respiratory pathway to maintain yeast morphology. Mitochondrial proteomics can aid in the identification of C. albicans genes not previously implicated in filamentation.
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Affiliation(s)
- Vincent F.Vellucci
- Department of Pediatrics and Program in Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06520
| | - Scott Gygax
- Antimicrobial Resistance Section, Molecular and Cellular Biology Division, Research and Development Department, Medical Diagnostic Laboratories, L.L.C. Hamilton, NJ 08690-3303
| | - Margaret K. Hostetter
- Department of Pediatrics and Program in Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06520
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19
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Rustad TR, Choiniere JH, Howard DH, White TC. The Candida albicans mating type like locus [MTL] is not involved in chlamydospore formation. Med Mycol 2006; 44:677-81. [PMID: 17071565 DOI: 10.1080/13693780600840914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Candida albicans produces chlamydospores, which can be used as a diagnostic tool for species identification. It has been suggested that these chlamydospores are degenerate spores. If so, then their production might be linked to the mating loci, and clinical strains that are homozygous for the C. albicans mating locus MTL may be altered in chlamydospore formation, which could cause problems in diagnostics and species identification. In Saccharomyces cerevisiae diploid cells, the heterodimeric transcriptional repressor formed by the products of the mating genes MATa1 and MATalpha2 is an important regulator of sporulation. It was therefore of interest to determine if the disruptions of the MATa1 and MATalpha2 homologs in C. albicans, MTLa1 and MTLalpha2, result in inhibition of chlamydospore formation. Laboratory strains containing disruptions of either the entire MTL locus or specific genes within the locus were assayed for their ability to form chlamydospores. Clinical strains that are homozygous for one of the two MTL loci were also assayed. No change in chlamydospore formation was seen in these strains compared to the standard laboratory strain.
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Affiliation(s)
- Tige R Rustad
- Department of Pathobiology, School of Public Health and Community Medicine, University of Washington, Seattle, WA, USA
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20
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Eisman B, Alonso-Monge R, Román E, Arana D, Nombela C, Pla J. The Cek1 and Hog1 mitogen-activated protein kinases play complementary roles in cell wall biogenesis and chlamydospore formation in the fungal pathogen Candida albicans. EUKARYOTIC CELL 2006; 5:347-58. [PMID: 16467475 PMCID: PMC1405885 DOI: 10.1128/ec.5.2.347-358.2006] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Hog1 mitogen-activated protein (MAP) kinase mediates an adaptive response to both osmotic and oxidative stress in the fungal pathogen Candida albicans. This protein also participates in two distinct morphogenetic processes, namely the yeast-to-hypha transition (as a repressor) and chlamydospore formation (as an inducer). We show here that repression of filamentous growth occurs both under serum limitation and under other partially inducing conditions, such as low temperature, low pH, or nitrogen starvation. To understand the relationship of the HOG pathway to other MAP kinase cascades that also play a role in morphological transitions, we have constructed and characterized a set of double mutants in which we deleted both the HOG1 gene and other signaling elements (the CST20, CLA4, and HST7 kinases, the CPH1 and EFG1 transcription factors, and the CPP1 protein phosphatase). We also show that Hog1 prevents the yeast-to-hypha switch independent of all the elements analyzed and that the inability of the hog1 mutants to form chlamydospores is suppressed when additional elements of the CEK1 pathway (CST20 or HST7) are altered. Finally, we report that Hog1 represses the activation of the Cek1 MAP kinase under basal conditions and that Cek1 activation correlates with resistance to certain cell wall inhibitors (such as Congo red), demonstrating a role for this pathway in cell wall biogenesis.
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Affiliation(s)
- B Eisman
- Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza de Ramón y Cajal s/n, E-28040 Madrid, Spain
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21
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Martin SW, Douglas LM, Konopka JB. Cell cycle dynamics and quorum sensing in Candida albicans chlamydospores are distinct from budding and hyphal growth. EUKARYOTIC CELL 2005; 4:1191-202. [PMID: 16002645 PMCID: PMC1168967 DOI: 10.1128/ec.4.7.1191-1202.2005] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The regulation of morphogenesis in the human fungal pathogen Candida albicans is under investigation to better understand how the switch between budding and hyphal growth is linked to virulence. Therefore, in this study we examined the ability of C. albicans to undergo a distinct type of morphogenesis to form large thick-walled chlamydospores whose role in infection is unclear, but they act as a resting form in other species. During chlamydospore morphogenesis, cells switch to filamentous growth and then develop elongated suspensor cells that give rise to chlamydospores. These filamentous cells were distinct from true hyphae in that they were wider and were not inhibited by the quorum-sensing factor farnesol. Instead, farnesol increased chlamydospore production, indicating that quorum sensing can also have a positive role. Nuclear division did not occur across the necks of chlamydospores, as it does in budding. Interestingly, nuclei divided within the suspensor cells, and then one daughter nucleus subsequently migrated into the chlamydospore. Septins were not detected near mitotic nuclei but were localized at chlamydospore necks. At later stages, septins localized throughout the chlamydospore plasma membrane and appeared to form long filamentous structures. Deletion of the CDC10 or CDC11 septins caused greater curvature of cells growing in a filamentous manner and morphological defects in suspensor cells and chlamydospores. These studies identify aspects of chlamydospore morphogenesis that are distinct from bud and hyphal morphogenesis.
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Affiliation(s)
- Stephen W Martin
- Department of Molecular Genetics and Microbiology, State University of New York, Stony Brook, NY 11794-5222, USA
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22
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Lin X, Heitman J. Chlamydospore formation during hyphal growth in Cryptococcus neoformans. EUKARYOTIC CELL 2005; 4:1746-54. [PMID: 16215181 PMCID: PMC1265899 DOI: 10.1128/ec.4.10.1746-1754.2005] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2005] [Accepted: 07/26/2005] [Indexed: 11/20/2022]
Abstract
Cryptococcus neoformans, a basidiomycetous fungal pathogen, infects hosts through inhalation and can cause fatal meningoencephalitis in individuals if untreated. This fungus undergoes a dimorphic transition from yeast to filamentous growth during mating and monokaryotic fruiting, which leads to the production of hyphae and airborne infectious basidiospores. Here we characterized a novel morphological feature associated with the filamentous stages of the life cycle of C. neoformans which resembles resting or survival structures known as chlamydospores in other fungi. The C. neoformans chlamydospore-like structure is rich in glycogen, suggesting that it might have a role as an energy store. However, characterization of mutants with decreased or increased levels of glycogen production showed that glycogen levels have little effect on filamentous growth, sporulation, or chlamydospore formation. These results suggest that the formation of chlamydospores is independent of glycogen accumulation level. We also show that chlamydospore formation does not require successful sporulation and that the presence of chlamydospores is not sufficient for sporulation. Although the biological functions of chlamydospores remain to be established for this pathogenic fungus, their formation appears to be an integral part of the filamentation process, suggesting that they could be necessary to support sexual sporulation under adverse conditions and thereby facilitate the production of infectious basidiospores or long-term survival propagules in harsh environments.
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Affiliation(s)
- Xiaorong Lin
- Department of Molecular Genetics and Microbiology, Howard Hughes Medical Institute, Room 322 CARL Building, Box 3546, Research Drive, Duke University Medical Center, Durham, North Carolina 27710, USA
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23
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Petraitiene R, Petraitis V, Kelaher AM, Sarafandi AA, Mickiene D, Groll AH, Sein T, Bacher J, Walsh TJ. Efficacy, plasma pharmacokinetics, and safety of icofungipen, an inhibitor of Candida isoleucyl-tRNA synthetase, in treatment of experimental disseminated candidiasis in persistently neutropenic rabbits. Antimicrob Agents Chemother 2005; 49:2084-92. [PMID: 15855534 PMCID: PMC1087633 DOI: 10.1128/aac.49.5.2084-2092.2005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Icofungipen (formerly PLD-118) is a synthetic derivative of the naturally occurring beta-amino acid cispentacin that blocks isoleucyl-tRNA synthetase, resulting in the inhibition of protein synthesis and growth of fungal cells. We investigated the efficacy, plasma pharmacokinetics, and safety of icofungipen in escalating dosages for the treatment of experimental subacute disseminated candidiasis in persistently neutropenic rabbits. Icofungipen was administered for 10 days starting 24 h after the intravenous inoculation of 10(3) Candida albicans blastoconidia. Study groups consisted of rabbits treated with icofungipen at 4 (ICO-4), 10 (ICO-10), and 25 (ICO-25) mg/kg of body weight/day in two divided dosages, rabbits treated with fluconazole at 10 mg/kg/day, rabbits treated with amphotericin B at 1 mg/kg/day, and untreated controls. Levels of icofungipen in plasma were derivatized by phthaldialdehyde and quantified by high-performance liquid chromatography with fluorescence detection. Rabbits treated with ICO-10 (P < 0.01) and ICO-25 (P < 0.001) showed significant dosage-dependent tissue clearance of C. albicans from the liver, spleen, kidney, brain, vitreous, vena cava, and lung in comparison to untreated controls. ICO-25 cleared C. albicans from all tissues and had activity comparable to that of amphotericin B versus untreated controls (P < 0.001). Pharmacokinetics of icofungipen in plasma approximated a dose-dependent relationship of the maximum concentration of drug in serum and the area under the concentration-time curve. There was no significant elevation of the levels of hepatic transaminases, alkaline phosphatase, bilirubin, urea nitrogen, or creatinine in icofungipen-treated rabbits. Icofungipen followed dose-dependent pharmacokinetics and was effective in the treatment of experimental disseminated candidiasis, including central nervous system infection, in persistently neutropenic rabbits.
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Affiliation(s)
- Ruta Petraitiene
- Immunocompromised Host Section, Pediatric Oncology Branch, National Cancer Institute, Bethesda, MD 20892-1100, USA
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24
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Palmer GE, Johnson KJ, Ghosh S, Sturtevant J. Mutant alleles of the essential 14-3-3 gene in Candida albicans distinguish between growth and filamentation. MICROBIOLOGY-SGM 2004; 150:1911-1924. [PMID: 15184577 DOI: 10.1099/mic.0.26910-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The opportunistic fungal pathogen Candida albicans has the ability to exploit diverse host environments and can either reside commensally or cause disease. In order to adapt to its new environment it must respond to new physical conditions, nutrient sources, and the host immune response. This requires the co-regulation of multiple signalling networks. The 14-3-3 family of proteins is highly conserved in all eukaryotic species. These proteins regulate signalling pathways involved in cell survival, the cell cycle, and differentiation, and effect their functions via interactions with phosphorylated serines/threonines. In C. albicans there is only one 14-3-3 protein, Bmh1p, and it is required for vegetative growth and optimal filamentation. In order to dissect separate functions of Bmh1p in C. albicans, site-directed nucleotide substitutions were made in the C. albicans BMH1 gene based on studies in other species. Putative temperature-sensitive, ligand-binding and dimerization mutants were constructed. In addition two mutant strains identified through random mutagenesis were analysed. All five mutant strains demonstrated varying defects in growth and filamentation. This paper begins to segregate functions of Bmh1p that are required for optimal growth and the different filamentation pathways. These mutant strains will allow the identification of 14-3-3 target interactions and correlate the individual functions of Bmh1p to cellular processes involved in pathogenesis.
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Affiliation(s)
- Glen E Palmer
- Georgetown University School of Medicine, Department of Microbiology and Immunology, 3900 Reservoir Road, Washington DC 20036, USA
- Louisiana State University School of Medicine, Department of Microbiology, Immunology, and Parasitology, Center of Excellence in Oral and Craniofacial Biology, 1100 Florida Ave, Box F8-130 New Orleans, LA 70119, USA
| | - Kevin J Johnson
- Louisiana State University School of Medicine, Department of Microbiology, Immunology, and Parasitology, Center of Excellence in Oral and Craniofacial Biology, 1100 Florida Ave, Box F8-130 New Orleans, LA 70119, USA
| | - Sumana Ghosh
- Louisiana State University School of Medicine, Department of Microbiology, Immunology, and Parasitology, Center of Excellence in Oral and Craniofacial Biology, 1100 Florida Ave, Box F8-130 New Orleans, LA 70119, USA
| | - Joy Sturtevant
- Georgetown University School of Medicine, Department of Microbiology and Immunology, 3900 Reservoir Road, Washington DC 20036, USA
- Louisiana State University School of Medicine, Department of Microbiology, Immunology, and Parasitology, Center of Excellence in Oral and Craniofacial Biology, 1100 Florida Ave, Box F8-130 New Orleans, LA 70119, USA
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25
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Alasio TM, Lento PA, Bottone EJ. Giant blastoconidia of Candida albicans. A case report and review of the literature. Arch Pathol Lab Med 2003; 127:868-71. [PMID: 12823045 DOI: 10.5858/2003-127-868-gboca] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We describe a patient with extranodal non-Hodgkin lymphoma who developed systemic candidiasis after treatment with a cyclophosphamide-based chemotherapy regimen. Histologically, the fungal organisms demonstrated markedly enlarged blastoconidia with a variety of morphologic forms, mimicking other mycotic organisms, such as Cryptococcus neoformans, Blastomyces dermatitidis, and Paracoccidioides brasiliensis. The in vivo occurrence of such giant forms is rare, and when observed histologically may result in an erroneous diagnosis or a diagnosis of multiple mycotic organisms.
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Affiliation(s)
- Teresa M Alasio
- Department of Pathology, The Mount Sinai Hospital, New York, NY 10029, USA.
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26
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Petraitis V, Petraitiene R, Groll AH, Roussillon K, Hemmings M, Lyman CA, Sein T, Bacher J, Bekersky I, Walsh TJ. Comparative antifungal activities and plasma pharmacokinetics of micafungin (FK463) against disseminated candidiasis and invasive pulmonary aspergillosis in persistently neutropenic rabbits. Antimicrob Agents Chemother 2002; 46:1857-69. [PMID: 12019101 PMCID: PMC127233 DOI: 10.1128/aac.46.6.1857-1869.2002] [Citation(s) in RCA: 157] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2001] [Revised: 11/25/2001] [Accepted: 02/25/2002] [Indexed: 11/20/2022] Open
Abstract
Micafungin (FK463) is an echinocandin that demonstrates potent in vitro antifungal activities against Candida and Aspergillus species. However, little is known about its comparative antifungal activities in persistently neutropenic hosts. We therefore investigated the plasma micafungin pharmacokinetics and antifungal activities of micafungin against experimental disseminated candidiasis and invasive pulmonary aspergillosis in persistently neutropenic rabbits. The groups with disseminated candidiasis studied consisted of untreated controls (UCs); rabbits treated with desoxycholate amphotericin B (DAMB) at 1 mg/kg of body weight/day; or rabbits treated with micafungin at 0.25, 0.5, 1, and 2 mg/kg/day intravenously. Compared with the UCs, rabbits treated with micafungin or DAMB showed significant dosage-dependent clearance of Candida albicans from the liver, spleen, kidney, brain, eye, lung, and vena cava. These in vivo findings correlated with the results of in vitro time-kill assays that demonstrated that micafungin has concentration-dependent fungicidal activity. The groups with invasive pulmonary aspergillosis studied consisted of UCs; rabbits treated with DAMB; rabbits treated with liposomal amphotericin B (LAMB) at 5 mg/kg/day; and rabbits treated with micafungin at 0.5, 1, and 2 mg/kg/day. In comparison to the significant micafungin dosage-dependent reduction of the residual burden (in log CFU per gram) of C. albicans in tissue, micafungin-treated rabbits with invasive pulmonary aspergillosis had no reduction in the concentration of Aspergillus fumigatus in tissue. DAMB and LAMB significantly reduced the burdens of C. albicans and A. fumigatus in tissues (P < 0.01). Persistent galactomannan antigenemia in micafungin-treated rabbits correlated with the presence of an elevated burden of A. fumigatus in pulmonary tissue. By comparison, DAMB- and LAMB-treated animals had significantly reduced circulating galactomannan antigen levels. Despite a lack of clearance of A. fumigatus from the lungs, there was a significant improvement in the rate of survival (P < 0.001) and a reduction in the level of pulmonary infarction (P < 0.05) in micafungin-treated rabbits. In summary, micafungin demonstrated concentration-dependent and dosage-dependent clearance of C. albicans from persistently neutropenic rabbits with disseminated candidiasis but not of A. fumigatus from persistently neutropenic rabbits with invasive pulmonary aspergillosis.
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Affiliation(s)
- Vidmantas Petraitis
- Immunocompromised Host Section, Pediatric Oncology Branch, National Cancer Institute, Bethesda, Maryland 20892, USA
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27
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Mukherjee PK, Seshan KR, Leidich SD, Chandra J, Cole GT, Ghannoum MA. Reintroduction of the PLB1 gene into Candida albicans restores virulence in vivo. MICROBIOLOGY (READING, ENGLAND) 2001; 147:2585-2597. [PMID: 11535799 DOI: 10.1099/00221287-147-9-2585] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Phospholipases have been proposed to contribute to the virulence of Candida albicans. Recently, a candidal strain deleted for PLB1, the gene encoding the predominant phospholipase B (Plb1) secreted by C. albicans, was constructed and its virulence in an intravenous murine model of disseminated candidiasis was evaluated. In the present study, the PLB1 gene was reintroduced back into the plb1 null mutant to generate the revertant strain, which showed similar growth and morphology to its isogenic parent strain. Virulence of the revertant strain was found to be comparable to that of the parent strain in an intravenous murine model of disseminated candidiasis. To compare the abilities of the plb1 null mutant, the revertant and the isogenic parent strains to cross the gastrointestinal (GI) tract and cause systemic infection, an oral-intragastric infant mouse model of candidiasis was used. Histological examinations and analysis of c.f.u. of the pathogen in liver homogenates revealed that the parental and revertant strains were able to invade and traverse the GI mucosa to a significantly greater extent than the plb1 null mutant. Immunofluorescence and immunoelectron microscopic studies of infected host tissue using anti-Plb1 antibody showed that Plb1 is secreted during invasion of the gastric mucosa by the parental and revertant strains. In contrast, little or no labelling was observed in the null mutant strain. The results indicate that the Plb1 secreted by C. albicans enhances the ability of this organism to cross the GI tract and disseminate haematogenously. These studies provide unequivocal evidence supporting a role for Plb1 during the course of infection by C. albicans.
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Affiliation(s)
- Pranab K Mukherjee
- Center for Medical Mycology, University Hospitals of Cleveland and Department of Dermatology, Case Western Reserve University, Cleveland, OH 44106-5028, USA1
| | - K R Seshan
- Department of Microbiology and Immunology, Medical College of Ohio, Toledo, OH 43614-5806, USA2
| | - S D Leidich
- Center for Medical Mycology, University Hospitals of Cleveland and Department of Dermatology, Case Western Reserve University, Cleveland, OH 44106-5028, USA1
| | - Jyotsna Chandra
- Center for Medical Mycology, University Hospitals of Cleveland and Department of Dermatology, Case Western Reserve University, Cleveland, OH 44106-5028, USA1
| | - Garry T Cole
- Department of Microbiology and Immunology, Medical College of Ohio, Toledo, OH 43614-5806, USA2
| | - Mahmoud A Ghannoum
- Center for Medical Mycology, University Hospitals of Cleveland and Department of Dermatology, Case Western Reserve University, Cleveland, OH 44106-5028, USA1
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28
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Sonneborn A, Bockmühl DP, Ernst JF. Chlamydospore formation in Candida albicans requires the Efg1p morphogenetic regulator. Infect Immun 1999; 67:5514-7. [PMID: 10496941 PMCID: PMC96916 DOI: 10.1128/iai.67.10.5514-5517.1999] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/1999] [Accepted: 06/30/1999] [Indexed: 11/20/2022] Open
Abstract
Chlamydospore formation of the fungal pathogen Candida albicans was found to depend on the Efg1 protein, which regulates the yeast-hyphal transition. Isogenic mutants lacking EFG1 or encoding T206A and T206E variants did not differentiate chlamydospores, while cek1, cph1, or tpk2 mutations had no effect. Furthermore, filamentation of efg1 cph1 double mutants in microaerophilic conditions suggests a novel Efg1p/Cph1p-independent filamentation pathway in C. albicans.
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Affiliation(s)
- A Sonneborn
- Institut für Mikrobiologie, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
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29
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Petraitiene R, Petraitis V, Groll AH, Candelario M, Sein T, Bell A, Lyman CA, McMillian CL, Bacher J, Walsh TJ. Antifungal activity of LY303366, a novel echinocandin B, in experimental disseminated candidiasis in rabbits. Antimicrob Agents Chemother 1999; 43:2148-55. [PMID: 10471556 PMCID: PMC89438 DOI: 10.1128/aac.43.9.2148] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The safety and antifungal activity of LY303366 (LY), a new broad-spectrum semisynthetic echinocandin, were studied against disseminated candidiasis in persistently neutropenic rabbits. In vitro time-kill assays demonstrated that LY has concentration-dependent fungicidal activity. The pharmacokinetics of LY in the plasma of nonneutropenic rabbits suggested a linear relationship between dose and area under the curve (AUC). The times spent above the MIC during the experimental dosing interval of 24 h were 4 h for LY at 0.1 mg/kg of body weight/day (LY0.1), 8 h for LY at 0.25 mg/kg/day (LY0.25), 12 h for LY at 0.5 mg/kg/day (LY0.5), and 20 h for LY at 1 mg/kg/day (LY1). Antifungal therapy was administered to infected rabbits for 10 days starting 24 h after the intravenous (i.v.) inoculation of 10(3) Candida albicans blastoconidia. Study groups consisted of untreated controls (UCs) and animals treated with amphotericin B (AmB; 1 mg/kg/day i.v.), fluconazole (FLU; 10 mg/kg/day i.v.), and LY0.1, LY0.25, LY0.5, or LY1 i.v. Rabbits treated with LY0.5, LY1, AmB, and FLU had similarly significant clearance of C. albicans from the liver, spleen, kidney, lung, vena cava, and brain in comparison to that for UCs. There was a dose-dependent clearance of C. albicans from tissues in response to LY. Among rabbits treated with LY0.1 there was a significant reduction of C. albicans only in the spleen. In animals treated with LY0.25 there was a significant reduction in all tissues but the brain. By comparison, LY0.5 and LY1 cleared all tissues, including the brain, of C. albicans. These in vivo findings were consistent with the results of in vitro time-kill assays. A dose-dependent effect of altered cell wall morphology was observed among UCs and animals treated with LY0.1, and LY0.25, with a progressive transition from hyphal structure to disrupted yeast forms. Serum creatinine levels were higher and serum potassium levels were lower in AmB-treated rabbits than in UCs and LY- and FLU-treated rabbits. LY0.5 and LY1 were well tolerated, displayed predictable pharmacokinetics in plasma, and had activities comparable to those of AmB and FLU in the treatment of disseminated candidiasis in persistently neutropenic rabbits.
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Affiliation(s)
- R Petraitiene
- Immunocompromised Host Section, Pediatric Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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Bottone EJ, Horga M, Abrams J. "Giant" blastoconidia of Candida albicans: morphologic presentation and concepts regarding their production. Diagn Microbiol Infect Dis 1999; 34:27-32. [PMID: 10342104 DOI: 10.1016/s0732-8893(99)00013-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Candida albicans normally produces blastoconidia measuring 2 to 8 microns in diameter. Markedly enlarged "giant" (approximately 30 microns) blastoconidia of a C. albicans isolate (designated BH) were observed after growth on commercially prepared chocolate agar already supplemented with IsoVitalex (BBL-Microbiology Systems, Cockeysville, MD, USA). Morphologically, "giant" blastoconidia presented a spectrum of forms such as blastoconidia with linear creases, with a single broad-based bud resembling Blastomyces dermatididis, with multiple buds resembling Paracoccidioides brasiliensis, or elliptical in shape. "Giant" blastoconidia contained a large oval clear vacuole occupying greater than 50% of the blastoconidium. Pseudohyphae emanating from these blastoconidia were also enlarged and contained a similar oval inclusion. Rarely observed were "giant" blastoconidia with either adherent or internalized blastoconidia uniformly arranged within the blastoconidium. "Giant" or enlarged blastoconidia production was constant, usually approaching 10 to 20% of the blastoconidial units comprising a single colony, irrespective of the number of subcultures. IsoVitalex supplementation of Remel (Lexana, KS, USA) chocolate agar but not a variety of other media also resulted in "giant" blastoconidia production. It is, therefore, theorized that a component(s) of IsoVitalex activates/blocks a gene present in select clones of C. albicans blastoconidia resulting in "giant" or enlarged blastoconidiogenesis.
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Affiliation(s)
- E J Bottone
- Department of Pediatrics, Mount Sinai Hospital, New York, NY 10029, USA
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Cole GT, Seshan KR, Lynn KT, Franco M. Gastrointestinal candidiasis: histopathology of Candida-host interactions in a murine model. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/s0953-7562(09)80126-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Cole GT, Saha K, Seshan KR, Lynn KT, Franco M, Wong PK. Retrovirus-induced immunodeficiency in mice exacerbates gastrointestinal candidiasis. Infect Immun 1992; 60:4168-78. [PMID: 1398927 PMCID: PMC257449 DOI: 10.1128/iai.60.10.4168-4178.1992] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Dysfunction of neutrophils in patients infected with human immunodeficiency virus is at least partly responsible for secondary microbial diseases in these individuals, including invasive gastrointestinal (GI) candidiasis. Immunoregulatory disturbances associated with the development of AIDS in human immunodeficiency virus-infected patients exacerbates Candida albicans infection of the upper GI tract and frequently leads to oropharyngeal and esophageal candidiasis. In this article, we present the first report of a murine model of invasive GI candidiasis associated with an AIDS-related murine immunodeficiency syndrome that results from infection of C57BL/6 mice with a previously described retrovirus complex (LP-BM5). Mice of the inbred strain were infected with C. albicans by oral-intragastric inoculation as infants and with the retrovirus by the intraperitoneal route 30 days later. Control mice of the same strain were infected with C. albicans as above and subsequently infected with the avirulent, ecotropic helper virus (MBI-5). Animals were killed 90 days after retroviral challenge. Total and differential blood cell counts, CD4+ T-cell counts in the spleen, and the histopathology of the gastric mucosa of experimental and control animals were determined. The virulent LP-BM5-infected animals developed murine AIDS and showed eruptive and suppurative lesions, with associated C. albicans mainly in regions of the cardial-atrium fold of the stomach. Well-defined abscesses with entrapped C. albicans hyphae were observed in the region of the cardial-atrium fold of control mice. A significant increase in the number of C. albicans CFU in homogenized and plated segments of the GI tract was recognized in mice with murine AIDS versus the control animals. The murine model of GI candidiasis reported here permits examination of the nature of C. albicans interaction with the gastric mucosa both in the immunocompetent host under conditions in which the yeast exists predominantly as a commensal organism and in the immunosuppressed host during progressive stages of AIDS induced by a retroviral infection.
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Affiliation(s)
- G T Cole
- Department of Botany, University of Texas, Austin 78713-7640
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