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Kondori N, Jaén-Luchoro D, Karlsson R, Abedzaedeh B, Hammarström H, Jönsson B. Exophiala species in household environments and their antifungal resistance profile. Sci Rep 2024; 14:17622. [PMID: 39085337 PMCID: PMC11291800 DOI: 10.1038/s41598-024-68166-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 07/22/2024] [Indexed: 08/02/2024] Open
Abstract
The black fungus Exophiala causes a wide range of infections from superficial to subcutaneous, but also invasive fungal infections in immunocompromised patients as well as healthy individuals. In addition, Exophiala, is a common colonizer of the air ways of patients with cystic fibrosis. However, the source of infection and mode of transmission is still unclear. The aim of this study was to investigate the presence of Exophiala in samples collected from Swedish indoor environments. We found that the Exophiala species were commonly found in dishwashers and that Exophiala dermatitidis was the most common Exophiala species, being identified in 70% (26 out of the 37) of samples. Almost all E. dermatitidis isolates had the ability to grow at 42 °C (P = 0.0002) and were catalase positive. Voriconazole and posaconazole exhibited the lowest MICs, while caspofungin and anidulafungin lack the antifungal activities in vitro. Future studies are needed to illuminate the transmission mode of the fungi.
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Affiliation(s)
- Nahid Kondori
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Box 7193, 402 34, Gothenburg, Sweden.
- Department of Clinical Microbiology, Sahlgrenska University Hospital, Region Västra Götaland, Gothenburg, Sweden.
| | - Daniel Jaén-Luchoro
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Box 7193, 402 34, Gothenburg, Sweden
- Department of Clinical Microbiology, Sahlgrenska University Hospital, Region Västra Götaland, Gothenburg, Sweden
| | - Roger Karlsson
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Box 7193, 402 34, Gothenburg, Sweden
- Department of Clinical Microbiology, Sahlgrenska University Hospital, Region Västra Götaland, Gothenburg, Sweden
- Nanoxis Consulting AB, Gothenburg, Sweden
| | - Bahman Abedzaedeh
- Department of Clinical Microbiology, Sahlgrenska University Hospital, Region Västra Götaland, Gothenburg, Sweden
| | - Helena Hammarström
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Box 7193, 402 34, Gothenburg, Sweden
- Department of Infectious Diseases, Sahlgrenska University Hospital, Region Västra Götaland, Gothenburg, Sweden
| | - Bodil Jönsson
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Box 7193, 402 34, Gothenburg, Sweden
- Department of Clinical Microbiology, Sahlgrenska University Hospital, Region Västra Götaland, Gothenburg, Sweden
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2
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Jusuf S, Dong PT. Chromophore-Targeting Precision Antimicrobial Phototherapy. Cells 2023; 12:2664. [PMID: 37998399 PMCID: PMC10670386 DOI: 10.3390/cells12222664] [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: 10/03/2023] [Revised: 11/11/2023] [Accepted: 11/18/2023] [Indexed: 11/25/2023] Open
Abstract
Phototherapy, encompassing the utilization of both natural and artificial light, has emerged as a dependable and non-invasive strategy for addressing a diverse range of illnesses, diseases, and infections. This therapeutic approach, primarily known for its efficacy in treating skin infections, such as herpes and acne lesions, involves the synergistic use of specific light wavelengths and photosensitizers, like methylene blue. Photodynamic therapy, as it is termed, relies on the generation of antimicrobial reactive oxygen species (ROS) through the interaction between light and externally applied photosensitizers. Recent research, however, has highlighted the intrinsic antimicrobial properties of light itself, marking a paradigm shift in focus from exogenous agents to the inherent photosensitivity of molecules found naturally within pathogens. Chemical analyses have identified specific organic molecular structures and systems, including protoporphyrins and conjugated C=C bonds, as pivotal components in molecular photosensitivity. Given the prevalence of these systems in organic life forms, there is an urgent need to investigate the potential impact of phototherapy on individual molecules expressed within pathogens and discern their contributions to the antimicrobial effects of light. This review delves into the recently unveiled key molecular targets of phototherapy, offering insights into their potential downstream implications and therapeutic applications. By shedding light on these fundamental molecular mechanisms, we aim to advance our understanding of phototherapy's broader therapeutic potential and contribute to the development of innovative treatments for a wide array of microbial infections and diseases.
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Affiliation(s)
- Sebastian Jusuf
- Division of Infectious Diseases, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA;
| | - Pu-Ting Dong
- Department of Microbiology, The Forsyth Institute, Boston, MA 02142, USA
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA 02115, USA
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3
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Loh JT, Lam KP. Fungal infections: Immune defense, immunotherapies and vaccines. Adv Drug Deliv Rev 2023; 196:114775. [PMID: 36924530 DOI: 10.1016/j.addr.2023.114775] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 03/05/2023] [Accepted: 03/07/2023] [Indexed: 03/17/2023]
Abstract
Invasive fungal infection is an under recognized and emerging global health threat. Recently, the World Health Organization (WHO) released the first ever list of health-threatening fungi to guide research and public health interventions to strengthen global response to fungi infections and antifungal resistance. Currently, antifungal drugs only demonstrate partial success in improving prognosis of infected patients, and this is compounded by the rapid evolution of drug resistance among fungi species. The increased prevalence of fungal infections in individuals with underlying immunological deficiencies reflects the importance of an intact host immune system in controlling mycoses, and further highlights immunomodulation as a potential new avenue for the treatment of disseminated fungal diseases. In this review, we will summarize how host innate immune cells sense invading fungi through their pattern recognition receptors, and subsequently initiate a series of effector mechanisms and adaptive immune responses to mediate fungal clearance. In addition, we will discuss emerging preclinical and clinical data on antifungal immunotherapies and fungal vaccines which can potentially expand our antifungal armamentarium in future.
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Affiliation(s)
- Jia Tong Loh
- Singapore Immunology Network, Agency for Science, Technology and Research, 8A Biomedical Grove, S138648, Republic of Singapore.
| | - Kong-Peng Lam
- Singapore Immunology Network, Agency for Science, Technology and Research, 8A Biomedical Grove, S138648, Republic of Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5, Science Drive 2, S117545, Republic of Singapore; School of Biological Sciences, College of Science, Nanyang Technological University, 60, Nanyang Drive, S637551, Republic of Singapore.
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4
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Zhang QQ, Shi J, Shen PY, Xi F, Qian CY, Zhang GH, Zhu HJ, Xiao HM. Exploring the Efficacy of Biocontrol Microbes against the Fungal Pathogen Botryosphaeria dothidea JNHT01 Isolated from Fresh Walnut Fruit. Foods 2022; 11:foods11223651. [PMID: 36429242 PMCID: PMC9689359 DOI: 10.3390/foods11223651] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/03/2022] [Accepted: 11/11/2022] [Indexed: 11/18/2022] Open
Abstract
Biological control by antagonistic microorganisms are an effective and environmentally friendly approach in postharvest disease management. In order to develop a biocontrol agent for fresh walnut fruit preservation, the potential biocontrol effects of Bacillus amyloliquefaciens RD.006 and Hanseniaspora uvarum FA.006 against the main fungal pathogen of walnuts were evaluated. Botryosphaeria species showed the highest detection, and the JNHT01 strain showed the strongest pathogenicity. Bot. dothidea JNHT01 caused gray mold and brown rot on fresh walnuts, and its incidence rate reached 100% after an 8 days incubation. The growth of this fungal strain can be promoted by lighting, with a maximum growth rate achieved at a pH of 7 and at 28 °C. B. amyloliquefaciens RD.006 and H. uvarum FA.006 supernatants at a concentration of 1-15% v/v showed antifungal activity. The mycelial growth inhibition rates of Bot. dothidea JNHT01 were 23.67-82.61% for B. amyloliquefaciens RD.006 and 1.45-21.74% for H. uvarum FA.006. During Bot. dothidea JNHT01 growth, the biomass, nucleic acid leakage, and malondialdehyde content gradually increased, while the DPPH scavenging capacity and SOD activity decreased. The B. amyloliquefaciens RD.006 and H. uvarum FA.006 strains showed antifungal activity by damaging fungal cell membranes and reducing fungal antioxidant activity. Moreover, the antifungal effect of B. amyloliquefaciens RD.006 was higher than that of H. uvarum FA.006. Hence, the RD.006 strain of B. amyloliquefaciens can be considered a potential biocontrol agent for the management of postharvest walnut diseases caused by Bot. dothidea.
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Affiliation(s)
- Qiu Qin Zhang
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China (H.M.X.)
| | - Jie Shi
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China (H.M.X.)
| | - Pei Yao Shen
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China (H.M.X.)
| | - Fei Xi
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China (H.M.X.)
| | - Cheng Yu Qian
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China (H.M.X.)
| | - Guo Hua Zhang
- Shandong Wukangxuan Modern Agriculture and Forestry Development Co., Ltd., Zoucheng 273519, China
| | - Hai Jun Zhu
- Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Hong Mei Xiao
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China (H.M.X.)
- Correspondence: ; Tel./Fax: +86-02584395618
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Wongsuk T, Homkaew A, Faksri K, Thongnak C. Multi-locus Sequence Typing and Whole Genome Sequence Analysis of Cryptococcus neoformans Isolated from Clinical Specimens in Vajira Hospital, Bangkok, Thailand. Mycopathologia 2020; 185:503-514. [PMID: 32440853 DOI: 10.1007/s11046-020-00456-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 05/12/2020] [Indexed: 12/17/2022]
Abstract
The basidiomycete yeast Cryptococcus neoformans causes disease in immunocompromized patients. Whole genome sequencing (WGS) technology provides insights into the molecular epidemiology of C. neoformans. However, the number of such studies is limited. Here we used WGS and multilocus sequence typing (MLST) to determine the genetic diversity of C. neoformans isolates and genetic structures of their populations among patients admitted to a single hospital in Bangkok, Thailand. Seven isolates from six patients collected during 1 year were identified as C. neoformans sensu stricto according to colony morphology, microscopy, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and nucleotide sequence analysis of internal transcribed sequences. These isolates were sensitive to the antifungal drugs amphotericin B, fluconazole, 5-flucytosine, voriconazole, itraconazole and posaconazole and were mating type α and molecular type VNI. MLST analysis identified ST4, ST5 and ST6. We further employed WGS to determine the genetic diversity and relationships of C. neoformans isolated here combined with C. neoformans sequences data acquired from a public database (n = 42). We used the data to construct a phylogenetic tree. WGS provided additional genomics data and achieved high discriminatory power for identifying C. neoformans isolates isolated in Thailand. This report further demonstrates the applicability of WGS analysis for conducting molecular epidemiology and provides insight into the genetic diversity of C. neoformans isolates from one hospital in Thailand.
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Affiliation(s)
- Thanwa Wongsuk
- Department of Clinical Pathology, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, 681 Samsen Road, Vajira District, Dusit, Bangkok, 10300, Thailand
| | - Anchalee Homkaew
- Microbiology Laboratory, Department of Central Laboratory and Blood Bank, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, Bangkok, Thailand
| | - Kiatichai Faksri
- Research and Diagnostic Center for Emerging Infectious Diseases, and Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Chuphong Thongnak
- Department of Clinical Pathology, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, 681 Samsen Road, Vajira District, Dusit, Bangkok, 10300, Thailand.
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Matsumoto Y, Azami S, Shiga H, Nagamachi T, Moriyama H, Yamashita Y, Yoshikawa A, Sugita T. Induction of signal transduction pathways related to the pathogenicity of Cryptococcus neoformans in the host environment. Drug Discov Ther 2020; 13:177-182. [PMID: 31534068 DOI: 10.5582/ddt.2019.01047] [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] [Indexed: 11/05/2022]
Abstract
Cryptococcus neoformans, a human pathogenic fungus, infects immunocompromised humans and causes serious diseases such as cerebral meningitis. C. neoformans controls the expression of virulence factors in response to the host environment via various signal transduction pathways. Understanding the molecular mechanisms involved in C. neoformans infection will contribute to the development of methods to prevent and treat C. neoformans-related diseases. C. neoformans produces virulence factors, such as a polysaccharide capsule and melanin, to escape host immunity. Several proteins of C. neoformans are reported to regulate production of the virulence factors. In this review, on the basis of studies using gene-deficient mutants of C. neoformans and animal infection models, we outline the signal transduction pathways involved in the regulation of virulence factors.
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Affiliation(s)
| | - Saki Azami
- Department of Microbiology, Meiji Pharmaceutical University
| | - Haruka Shiga
- Department of Microbiology, Meiji Pharmaceutical University
| | - Tae Nagamachi
- Department of Microbiology, Meiji Pharmaceutical University
| | | | - Yuki Yamashita
- Department of Microbiology, Meiji Pharmaceutical University
| | | | - Takashi Sugita
- Department of Microbiology, Meiji Pharmaceutical University
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7
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Xisto MIDDS, Henao JEM, Dias LDS, Santos GMP, Calixto RDOR, Bernardino MC, Taborda CP, Barreto-Bergter E. Glucosylceramides From Lomentospora prolificans Induce a Differential Production of Cytokines and Increases the Microbicidal Activity of Macrophages. Front Microbiol 2019; 10:554. [PMID: 30967849 PMCID: PMC6440385 DOI: 10.3389/fmicb.2019.00554] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 03/04/2019] [Indexed: 11/16/2022] Open
Abstract
Lomentospora prolificans is an emerging opportunistic fungus with a high resistance to antifungal agents and it can cause localized infections in immunocompetent patients and disseminated infections with a high mortality rate in immunosuppressed patients. Glucosylceramides (GlcCer) are synthetized in the majority of known fungal pathogens. They are bioactive molecules presenting different functions, such as involvement in fungal growth and morphological transitions in several fungi. The elucidation of the primary structure of the fungal surface glycoconjugates could contribute for the understanding of the mechanisms of pathogenicity. In this work, GlcCer species were isolated from mycelium and conidia forms of L. prolificans and their chemical structures were elucidated by mass spectrometry (ESI-MS). GlcCer purified from both forms presented a major species at m/z 750 that corresponds to N-2-hydroxyhexadecanoyl-1-β-D-glucopyranosyl-9-methyl-4,8-sphingadienine. Monoclonal antibodies against GlcCer could recognize L. prolificans GlcCer species from mycelium and conidia, suggesting a conserved epitope in fungal GlcCer. In addition, in vivo assays showed that purified GlcCer species from both forms was able to induce a high secretion of pro-inflammatory cytokines by splenocytes. GlcCer species also promote the recruitment of polymorphonuclear, eosinophils, small peritoneal macrophage (SPM) and mononuclear cells to the peritoneal cavity. GlcCer species were also able to induce the oxidative burst by peritoneal macrophages with NO and superoxide radicals production, and to increase the killing of L. prolificans conidia by peritoneal macrophages. These results indicate that GlcCer species from L. prolificans are a potent immune response activator.
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Affiliation(s)
- Mariana Ingrid Dutra da Silva Xisto
- Laboratório de Química Biológica de Microrganismos, Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Julián Esteban Muñoz Henao
- Studies in Translational Microbiology and Emerging Diseases Research Group, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia
| | - Lucas Dos Santos Dias
- Institute of Biomedical Sciences, Department of Microbiology, Medical Mycology Laboratory, Medical School and Tropical Medicine Institute, University of São Paulo, São Paulo, Brazil.,Department of Pediatric, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
| | - Giulia Maria Pires Santos
- Instituto Biomédico, Departamento de Microbiologia e Parasitologia, Universidade Federal Fluminense, Niterói, Brazil
| | - Renata de Oliveira Rocha Calixto
- Laboratório de Química Biológica de Microrganismos, Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Mariana Collodetti Bernardino
- Laboratório de Química Biológica de Microrganismos, Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Carlos Pelleschi Taborda
- Institute of Biomedical Sciences, Department of Microbiology, Medical Mycology Laboratory, Medical School and Tropical Medicine Institute, University of São Paulo, São Paulo, Brazil
| | - Eliana Barreto-Bergter
- Laboratório de Química Biológica de Microrganismos, Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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8
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The 'Amoeboid Predator-Fungal Animal Virulence' Hypothesis. J Fungi (Basel) 2019; 5:jof5010010. [PMID: 30669554 PMCID: PMC6463022 DOI: 10.3390/jof5010010] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 01/15/2019] [Accepted: 01/19/2019] [Indexed: 01/22/2023] Open
Abstract
The observation that some aspects of amoeba-fungal interactions resemble animal phagocytic cell-fungal interactions, together with the finding that amoeba passage can enhance the virulence of some pathogenic fungi, has stimulated interest in the amoeba as a model system for the study of fungal virulence. Amoeba provide a relatively easy and cheap model system where multiple variables can be controlled for the study of fungi-protozoal (amoeba) interactions. Consequently, there have been significant efforts to study fungal⁻amoeba interactions in the laboratory, which have already provided new insights into the origin of fungal virulence as well as suggested new avenues for experimentation. In this essay we review the available literature, which highlights the varied nature of amoeba-fungal interactions and suggests some unsolved questions that are potential areas for future investigation. Overall, results from multiple independent groups support the 'amoeboid predator⁻fungal animal virulence hypothesis', which posits that fungal cell predation by amoeba can select for traits that also function during animal infection to promote their survival and thus contribute to virulence.
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Silva RLH, Rosa-Milani E, Brunaldi MO, Maffei CML. Murine model of invasive pulmonary Aspergillosis: Follow-up of tissue injury, fungal burden and mortality with distinct elastase production strains. J Mycol Med 2018; 29:112-119. [PMID: 30446390 DOI: 10.1016/j.mycmed.2018.10.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 10/15/2018] [Accepted: 10/16/2018] [Indexed: 10/27/2022]
Abstract
To study invasive pulmonary Aspergillosis (IPA), we depleted neutrophils in mice using the monoclonal antibody anti-Gr-1/Ly-6G. Immunocompetent and neutropenic mice were infected via intratracheal with conidia of Aspergillus fumigatus clinical isolates, characterized as either higher or lower elastase producers. Neutropenic animals exhibited 100% mortality in 5 days, for both strains, and were observed survival curves overlapped, lungs with angioinvasion, rupture of bronchial and vascular walls, associated with exuberance of conidia filamentation. The immunocompetent animals infected with the lower elastase producer strain presented with upregulated inflammatory processes, and a lack of conidia filamentation in the tissue. The fungal burden in the lungs was not different in the immunocompetent and neutropenic groups. These findings confirm the protective role of neutrophils against A. fumigatus and suggest that the fungal elastinolytic activity is not a critical virulence factor but may be involved in tissue injury.
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Affiliation(s)
- R L H Silva
- Department of Pathology and Legal Medicine, Ribeirão Preto Medical School, University of São Paulo, Avenida Bandeirantes, 3900 Ribeirão Preto, 14049-900 São Paulo, Brazil.
| | - E Rosa-Milani
- Department of Cellular and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Avenida Bandeirantes, 3900 Ribeirão Preto, 14049-900 São Paulo Brazil.
| | - M O Brunaldi
- Department of Pathology and Legal Medicine, Ribeirão Preto Medical School, University of São Paulo, Avenida Bandeirantes, 3900 Ribeirão Preto, 14049-900 São Paulo, Brazil.
| | - C M L Maffei
- Department of Cellular and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Avenida Bandeirantes, 3900 Ribeirão Preto, 14049-900 São Paulo Brazil.
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10
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Tian L, Liu L, Yin Y, Huang M, Chen Y, Xu X, Wu P, Li M, Wu G, Jiang H, Chen Y. Heterogeneity in the expression and subcellular localization of POLYOL/MONOSACCHARIDE TRANSPORTER genes in Lotus japonicus. PLoS One 2017; 12:e0185269. [PMID: 28931056 PMCID: PMC5607196 DOI: 10.1371/journal.pone.0185269] [Citation(s) in RCA: 11] [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: 03/09/2017] [Accepted: 09/08/2017] [Indexed: 11/23/2022] Open
Abstract
Polyols can serve as a means for the translocation of carbon skeletons and energy between source and sink organs as well as being osmoprotective solutes and antioxidants which may be involved in the resistance of some plants to biotic and abiotic stresses. Polyol/Monosaccharide transporter (PLT) proteins previously identified in plants are involved in the loading of polyols into the phloem and are reported to be located in the plasma membrane. The functions of PLT proteins in leguminous plants are not yet clear. In this study, a total of 14 putative PLT genes (LjPLT1-14) were identified in the genome of Lotus japonicus and divided into 4 clades based on phylogenetic analysis. Different patterns of expression of LjPLT genes in various tissues were validated by qRT-PCR analysis. Four genes (LjPLT3, 4, 11, and 14) from clade II were expressed at much higher levels in nodule than in other tissues. Moreover, three of these genes (LjPLT3, 4, and 14) showed significantly increased expression in roots after inoculation with Mesorhizobium loti. Three genes (LjPLT1, 3, and 9) responded when salinity and/or osmotic stresses were applied to L. japonicus. Transient expression of GFP-LjPLT fusion constructs in Arabidopsis and Nicotiana benthamiana protoplasts indicated that the LjPLT1, LjPLT6 and LjPLT7 proteins are localized to the plasma membrane, but LjPLT2 (clade IV), LjPLT3, 4, 5 (clade II) and LjPLT8 (clade III) proteins possibly reside in the Golgi apparatus. The results suggest that members of the LjPLT gene family may be involved in different biological processes, several of which may potentially play roles in nodulation in this nitrogen-fixing legume.
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Affiliation(s)
- Lu Tian
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
- University of Chinese Academy of Sciences, Beijing, PR China
| | - Leru Liu
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
- University of Chinese Academy of Sciences, Beijing, PR China
| | - Yehu Yin
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
- University of Chinese Academy of Sciences, Beijing, PR China
| | - Mingchao Huang
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
- University of Chinese Academy of Sciences, Beijing, PR China
| | - Yanbo Chen
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
- University of Chinese Academy of Sciences, Beijing, PR China
| | - Xinlan Xu
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
| | - Pingzhi Wu
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
| | - Meiru Li
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
| | - Guojiang Wu
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
| | - Huawu Jiang
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
| | - Yaping Chen
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China
- * E-mail:
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Ohn J, Choe YS, Park J, Mun JH. Dermoscopic patterns of fungal melanonychia: A comparative study with other causes of melanonychia. J Am Acad Dermatol 2017; 76:488-493.e2. [DOI: 10.1016/j.jaad.2016.08.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 08/03/2016] [Accepted: 08/08/2016] [Indexed: 10/20/2022]
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12
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Zhao L, Jiang J, Zhu Z, Liao Z, Yao X, Yang Y, Cao Y, Jiang Y. Lysine enhances the effect of amphotericin B against Candida albicans in vitro. Acta Biochim Biophys Sin (Shanghai) 2016; 48:182-93. [PMID: 26711896 DOI: 10.1093/abbs/gmv125] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 10/18/2015] [Indexed: 01/11/2023] Open
Abstract
Amphotericin B (AmB) is a polyene antibiotic produced by Streptomyces nodosus and has been used for >50 years in the treatment of acute systemic fungal infections. In the present study, we demonstrated that lysine, an essential amino acid, could enhance the effect of AmB against Candida albicans in vitro, although lysine itself did not exert a fungicidal effect. In addition, the combination of AmB with lysine could provide an enhanced action against Candida parapsilosis and Cryptococcus neoformans compared with AmB alone. Lysine could also enhance the antifungal effect of caspofungin or nystatin. An enhanced effect of the combination of lysine with AmB was observed for the prevention of biofilm and hypha formation. Furthermore, our results demonstrated that lysine-mediated oxidative damage, such as the generation of endogenous reactive oxygen species, may be the mechanism underlying the enhancing effect of lysine on AmB. Our results also showed that CaMCA1 gene plays an important role in increasing the sensitivity of C. albicans cells upon AmB treatment. Using AmB together with lysine may be a promising strategy for the therapy of disseminated candidiasis.
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Affiliation(s)
- Liuya Zhao
- School of Pharmacy, Second Military Medical University, Shanghai 200433, China Pharmacy Department, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Jingchen Jiang
- School of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Zhenyu Zhu
- School of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Zebin Liao
- School of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Xiangwen Yao
- School of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Yu Yang
- School of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Yingying Cao
- School of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Yuanying Jiang
- School of Pharmacy, Second Military Medical University, Shanghai 200433, China
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Lin J, Chen J, He J, Chen J, Yan Q, Zhou J, Xie P. Effects of microcystin-LR on bacterial and fungal functional genes profile in rat gut. Toxicon 2015; 96:50-6. [PMID: 25617596 DOI: 10.1016/j.toxicon.2015.01.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 10/29/2014] [Accepted: 01/20/2015] [Indexed: 10/24/2022]
Abstract
The short-term exposure to microcystin-LR (MC-LR, one of the most common and toxic variants generated by toxigenic cyanobacteria) induced gut dysfunction such as generation of reactive oxygen species, cell erosion and deficient intestinal absorption of nutrients. However, till now, little is known about its impact on gut microbial community, which has been considered as necessary metabolic assistant and stresses resistant entities for the host. This study was designed to reveal the shift of microbial functional genes in the gut of rat orally gavaged with MC-LR. GeoChip detected a high diversity of bacterial and fungal genes involved in basic metabolic processes and stress resistance. The results showed that the composition of functional genes was significantly changed in rat gut after one week of exposure to MC-LR, and we found some relatively enriched genes that are involved in carbon degradation including chitin, starch and limonene metabolism, and these genes were mainly derived from fungal and bacterial pathogens. In addition, we found large amounts of significantly enriched genes relevant to degradation of the specific carbon compounds, aromatics. The dysbiosis of bacterial and fungal flora gave an implication of pathogens invasion. The enriched gene functions could be linked to acute gastroenteritis induced by MC-LR.
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Affiliation(s)
- Juan Lin
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory for Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China; Graduate University of Chinese Academy of Sciences, Beijing 10049, PR China
| | - Jun Chen
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory for Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China
| | - Jun He
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory for Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China; Graduate University of Chinese Academy of Sciences, Beijing 10049, PR China
| | - Jing Chen
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory for Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China; Graduate University of Chinese Academy of Sciences, Beijing 10049, PR China
| | - Qingyun Yan
- Key Laboratory of Biodiversity and Conservation of Aquatic Organisms, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Jizhong Zhou
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Ping Xie
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory for Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China.
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14
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Lysøe E, Harris LJ, Walkowiak S, Subramaniam R, Divon HH, Riiser ES, Llorens C, Gabaldón T, Kistler HC, Jonkers W, Kolseth AK, Nielsen KF, Thrane U, Frandsen RJN. The genome of the generalist plant pathogen Fusarium avenaceum is enriched with genes involved in redox, signaling and secondary metabolism. PLoS One 2014; 9:e112703. [PMID: 25409087 PMCID: PMC4237347 DOI: 10.1371/journal.pone.0112703] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 10/13/2014] [Indexed: 12/03/2022] Open
Abstract
Fusarium avenaceum is a fungus commonly isolated from soil and associated with a wide range of host plants. We present here three genome sequences of F. avenaceum, one isolated from barley in Finland and two from spring and winter wheat in Canada. The sizes of the three genomes range from 41.6–43.1 MB, with 13217–13445 predicted protein-coding genes. Whole-genome analysis showed that the three genomes are highly syntenic, and share>95% gene orthologs. Comparative analysis to other sequenced Fusaria shows that F. avenaceum has a very large potential for producing secondary metabolites, with between 75 and 80 key enzymes belonging to the polyketide, non-ribosomal peptide, terpene, alkaloid and indole-diterpene synthase classes. In addition to known metabolites from F. avenaceum, fuscofusarin and JM-47 were detected for the first time in this species. Many protein families are expanded in F. avenaceum, such as transcription factors, and proteins involved in redox reactions and signal transduction, suggesting evolutionary adaptation to a diverse and cosmopolitan ecology. We found that 20% of all predicted proteins were considered to be secreted, supporting a life in the extracellular space during interaction with plant hosts.
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Affiliation(s)
- Erik Lysøe
- Department of Plant Health and Plant Protection, Bioforsk - Norwegian Institute of Agricultural and Environmental Research, Ås, Norway
- * E-mail:
| | - Linda J. Harris
- Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, Ottawa, Canada
| | - Sean Walkowiak
- Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, Ottawa, Canada
- Department of Biology, Carleton University, Ottawa, Canada
| | - Rajagopal Subramaniam
- Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, Ottawa, Canada
- Department of Biology, Carleton University, Ottawa, Canada
| | - Hege H. Divon
- Section of Mycology, Norwegian Veterinary Institute, Oslo, Norway
| | - Even S. Riiser
- Department of Plant Health and Plant Protection, Bioforsk - Norwegian Institute of Agricultural and Environmental Research, Ås, Norway
| | | | - Toni Gabaldón
- Bioinformatics and Genomics Programme, Centre for Genomic Regulation, Barcelona, Spain
- Universitat Pompeu Fabra, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
| | - H. Corby Kistler
- ARS-USDA, Cereal Disease Laboratory, St. Paul, Minnesota, United States of America
| | - Wilfried Jonkers
- ARS-USDA, Cereal Disease Laboratory, St. Paul, Minnesota, United States of America
| | - Anna-Karin Kolseth
- Department of Crop Production Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Kristian F. Nielsen
- Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - Ulf Thrane
- Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
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15
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Nimmanee P, Woo PCY, Kummasook A, Vanittanakom N. Characterization of sakA gene from pathogenic dimorphic fungus Penicillium marneffei. Int J Med Microbiol 2014; 305:65-74. [PMID: 25466206 DOI: 10.1016/j.ijmm.2014.11.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 11/01/2014] [Accepted: 11/04/2014] [Indexed: 12/18/2022] Open
Abstract
Eukaryotes utilize stress activated protein kinase (SAPK) pathways to adapt to environmental stress, including heat, osmotic, oxidative or nutrient stresses. Penicillium marneffei (Talaromyces marneffei), the dimorphic pathogenic fungus that can cause disseminated mycosis in HIV-infected patients, has to encounter various types of stresses both outside and inside host cells. However, the strategies used by this fungus in response to these stresses are still unclear. In this report, the stress-activated kinase (sakA) gene of P. marneffei was characterized and the roles of this gene on various stress conditions were studied. The sakA gene deletion mutant was constructed using the split marker method. The phenotypes and sensitivities to varieties of stresses, including osmotic, oxidative, heat and cell wall stresses of the deletion mutant were compared with the wild type and the sakA complemented strains. Results demonstrated that the P. marneffei sakA gene encoded a putative protein containing TXY phosphorylation lip found in the stress high osmolarity glycerol 1 (Hog1)/Spc1/p38 MAPK family, and that this gene was involved not only in tolerance against oxidative and heat stresses, but also played a role in asexual development, chitin deposition, yeast cell generation in vitro and survival inside mouse and human macrophages.
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Affiliation(s)
- Panjaphorn Nimmanee
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Patrick C Y Woo
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
| | - Aksarakorn Kummasook
- Division of Clinical Microbiology, Department of Medical Technology, School of Allied Health Sciences, University of Phayao, Phayao, Thailand
| | - Nongnuch Vanittanakom
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
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16
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Gazdag Z, Kálmán N, Blaskó A, Virág E, Belágyi J, Pesti M. Regulation of the unbalanced redox state in a Schizosaccharomyces pombe tert-butyl hydroperoxide-resistant mutant. ACTA BIOLOGICA HUNGARICA 2014; 65:218-26. [PMID: 24873914 DOI: 10.1556/abiol.65.2014.2.9] [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] [Indexed: 11/19/2022]
Abstract
The one-gene mutation in the tert-butyl hydroperoxide-resistant mutant hyd1-190 of the fission yeast Schizosaccharomyces pombe led to a 4-fold increase in resistance to t-BuOOH and decreased specific concentrations of superoxide and total thiols in comparison with the parental strain hyd+. It suggested an unbalanced redox state of the cells, which induced continuously increased specific activities of glutathione peroxidase, glutathione reductase and glutathione S-transferase and decreased activities of the antioxidant enzymes superoxide dismutases and glucose-6-phosphate dehydrogenase to regulate the redox balance of the mutation-induced permanent, low-level but tolerable internal stress. These results may contribute to the understanding of internal, oxidative stress-related human diseases.
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Affiliation(s)
- Z Gazdag
- University of Pécs Department of General and Environmental Microbiology, Faculty of Sciences Pécs Hungary
| | - Nikoletta Kálmán
- University of Pécs Department of General and Environmental Microbiology, Faculty of Sciences Pécs Hungary
| | - Agnes Blaskó
- University of Pécs Institute of Bioanalysis, Faculty of Medicine Pécs Hungary
| | - Eszter Virág
- University of Pécs Department of General and Environmental Microbiology, Faculty of Sciences Pécs Hungary
| | - J Belágyi
- University of Pécs Institute of Biophysics, Faculty of Medicine Pécs Hungary
| | - M Pesti
- University of Pécs Department of General and Environmental Microbiology, Faculty of Sciences Pécs Hungary
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17
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Kim JH, Mahoney N, Chan KL, Campbell BC, Haff RP, Stanker LH. Use of benzo analogs to enhance antimycotic activity of kresoxim methyl for control of aflatoxigenic fungal pathogens. Front Microbiol 2014; 5:87. [PMID: 24639673 PMCID: PMC3945611 DOI: 10.3389/fmicb.2014.00087] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 02/18/2014] [Indexed: 01/27/2023] Open
Abstract
The aim of this study was to examine two benzo analogs, octylgallate (OG) and veratraldehyde (VT), as antifungal agents against strains of Aspergillus parasiticus and A.flavus (toxigenic or atoxigenic). Both toxigenic and atoxigenic strains used were capable of producing kojic acid, another cellular secondary product. A. fumigatus was used as a genetic model for this study. When applied independently, OG exhibits considerably higher antifungal activity compared to VT. The minimum inhibitory concentrations (MICs) of OG were 0.3–0.5 mM, while that of VT were 3.0–5.0 mM in agar plate-bioassays. OG or VT in concert with the fungicide kresoxim methyl (Kre-Me; strobilurin) greatly enhanced sensitivity of Aspergillus strains to Kre-Me. The combination with OG also overcame the tolerance of A. fumigatus mitogen-activated protein kinase (MAPK) mutants to Kre-Me. The degree of compound interaction resulting from chemosensitization of the fungi by OG was determined using checkerboard bioassays, where synergistic activity greatly lowered MICs or minimum fungicidal concentrations. However, the control chemosensitizer benzohydroxamic acid, an alternative oxidase inhibitor conventionally applied in concert with strobilurin, did not achieve synergism. The level of antifungal or chemosensitizing activity was also “compound—strain” specific, indicating differential susceptibility of tested strains to OG or VT, and/or heat stress. Besides targeting the antioxidant system, OG also negatively affected the cell wall-integrity pathway, as determined by the inhibition of Saccharomyces cerevisiae cell wall-integrity MAPK pathway mutants. We concluded that certain benzo analogs effectively inhibit fungal growth. They possess chemosensitizing capability to increase efficacy of Kre-Me and thus, could reduce effective dosages of strobilurins and alleviate negative side effects associated with current antifungal practices. OG also exhibits moderate antiaflatoxigenic activity.
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Affiliation(s)
- Jong H Kim
- Foodborne Toxin Detection and Prevention Research Unit, Western Regional Research Center, USDA-ARS Albany, CA, USA
| | - Noreen Mahoney
- Foodborne Toxin Detection and Prevention Research Unit, Western Regional Research Center, USDA-ARS Albany, CA, USA
| | - Kathleen L Chan
- Foodborne Toxin Detection and Prevention Research Unit, Western Regional Research Center, USDA-ARS Albany, CA, USA
| | - Bruce C Campbell
- Foodborne Toxin Detection and Prevention Research Unit, Western Regional Research Center, USDA-ARS Albany, CA, USA
| | - Ronald P Haff
- Foodborne Toxin Detection and Prevention Research Unit, Western Regional Research Center, USDA-ARS Albany, CA, USA
| | - Larry H Stanker
- Foodborne Toxin Detection and Prevention Research Unit, Western Regional Research Center, USDA-ARS Albany, CA, USA
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18
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Liu T, Xu X, Leng W, Xue Y, Dong J, Jin Q. Analysis of gene expression changes in Trichophyton rubrum after skin interaction. J Med Microbiol 2014; 63:642-648. [PMID: 24586032 PMCID: PMC4042497 DOI: 10.1099/jmm.0.059386-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Trichophyton rubrum, an anthropophilic and cosmopolitan fungus, is the most common agent of superficial mycoses. In this study, T. rubrum infection was modelled by adding human skin sections to a limited medium containing glucose and cDNA microarrays were used to monitor T. rubrum gene expression patterns on a global level. We observed that exposure to human skin resulted in upregulation of the expression levels of T. rubrum genes related to many cellular and biological processes, including transcription and translation, metabolism and secondary transport, the stress response, and signalling pathways. These results provide a reference set of T. rubrum genes whose expression patterns change upon infection and reveal previously unknown genes that most likely correspond to proteins that should be considered as virulence factor candidates and potential new drug targets for T. rubrum infection.
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Affiliation(s)
- Tao Liu
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, PR China
| | - Xingye Xu
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, PR China
| | - Wenchuan Leng
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, PR China
| | - Ying Xue
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, PR China
| | - Jie Dong
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, PR China
| | - Qi Jin
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, PR China
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19
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Pongpom M, Sawatdeechaikul P, Kummasook A, Khanthawong S, Vanittanakom N. Antioxidative and immunogenic properties of catalase-peroxidase protein inPenicillium marneffei. Med Mycol 2013; 51:835-42. [DOI: 10.3109/13693786.2013.807445] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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21
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Maksimov IV, Yarullina LG, Burkhanova GF, Zaikina EA. Relationship between the aggressiveness and catalase activity of Septoria nodorum Berk. in wheat. BIOL BULL+ 2013. [DOI: 10.1134/s1062359013050099] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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22
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The polyketide synthase gene pks4 of Trichoderma reesei provides pigmentation and stress resistance. EUKARYOTIC CELL 2013; 12:1499-508. [PMID: 24036343 DOI: 10.1128/ec.00103-13] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Species of the fungal genus Trichoderma (Hypocreales, Ascomycota) are well-known for their production of various secondary metabolites. Nonribosomal peptides and polyketides represent a major portion of these products. In a recent phylogenomic investigation of Trichoderma polyketide synthase (PKS)-encoding genes, the pks4 from T. reesei was shown to be an orthologue of pigment-forming PKSs involved in synthesis of aurofusarin and bikaverin in Fusarium spp. In this study, we show that deletion of this gene in T. reesei results in loss of green conidial pigmentation and in pigmentation alteration of teleomorph structures. It also has an impact on conidial cell wall stability and the antagonistic abilities of T. reesei against other fungi, including formation of inhibitory metabolites. In addition, deletion of pks4 significantly influences the expression of other PKS-encoding genes of T. reesei. To our knowledge, this is the first indication that a low-molecular-weight pigment-forming PKS is involved in defense, mechanical stability, and stress resistance in fungi.
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23
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Kálmán N, Gazdag Z, Čertík M, Belágyi J, Selim SA, Pócsi I, Pesti M. Adaptation totert-butyl hydroperoxide at a plasma membrane level in the fission yeastSchizosaccharomyces pombeparental strain and itst-BuOOH-resistant mutant. J Basic Microbiol 2013; 54:215-25. [DOI: 10.1002/jobm.201200580] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Accepted: 11/23/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Nikoletta Kálmán
- Department of General and Environmental Microbiology, Faculty of Sciences, University of Pécs, Pécs, Hungary
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24
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Shirazi F, Kontoyiannis DP. Mitochondrial respiratory pathways inhibition in Rhizopus oryzae potentiates activity of posaconazole and itraconazole via apoptosis. PLoS One 2013; 8:e63393. [PMID: 23696824 PMCID: PMC3656966 DOI: 10.1371/journal.pone.0063393] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 04/03/2013] [Indexed: 11/19/2022] Open
Abstract
The incidence of mucormycosis has increased drastically in immunocompromised patients. Also the array of targets whose inhibition results in Mucorales death is limited. Recently, researchers identified mitochondria as important regulators of detoxification and virulence mechanisms in fungi. In this context, targeting the mitochondrial respiratory chain may provide a new platform for antifungal development. We hypothesized that targeting respiratory pathways potentiates triazoles activity via apoptosis. We found that simultaneous administration of antimycin A (AA) and benzohydroxamate (BHAM), inhibitors of classical and alternative mitochondrial pathways respectively, resulted in potent activity of posaconazole (PCZ) and itraconazole (ICZ) against Rhizopus oryzae. We observed cellular changes characteristic of apoptosis in R. oryzae cells treated with PCZ or ICZ in combination with AA and BHAM. The fungicidal activity of this combination against R. oryzae was correlated with intracellular reactive oxygen species accumulation (ROS), phosphatidylserine externalization, mitochondrial membrane depolarization, and increased caspase like activity. DNA fragmentation and condensation assays also revealed apoptosis of R. oryzae cells. These apoptotic features were prevented by the addition of the ROS scavenger N-acetyl-cysteine. Taken together, these findings suggest that the use of PCZ or ICZ in combination with AA and BHAM makes R. oryzae exquisitely sensitive to treatment with triazoles via apoptosis. This strategy may serve as a new model for the development of improved or novel antifungal agents.
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Affiliation(s)
- Fazal Shirazi
- Department of Infectious Diseases, Infection Control and Employee Health, Unit 402, University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Dimitrios P. Kontoyiannis
- Department of Infectious Diseases, Infection Control and Employee Health, Unit 402, University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
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25
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Redundant catalases detoxify phagocyte reactive oxygen and facilitate Histoplasma capsulatum pathogenesis. Infect Immun 2013; 81:2334-46. [PMID: 23589579 DOI: 10.1128/iai.00173-13] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Histoplasma capsulatum is a respiratory pathogen that infects phagocytic cells. The mechanisms allowing Histoplasma to overcome toxic reactive oxygen molecules produced by the innate immune system are an integral part of Histoplasma's ability to survive during infection. To probe the contribution of Histoplasma catalases in oxidative stress defense, we created and analyzed the virulence defects of mutants lacking CatB and CatP, which are responsible for extracellular and intracellular catalase activities, respectively. Both CatB and CatP protected Histoplasma from peroxide challenge in vitro and from antimicrobial reactive oxygen produced by human neutrophils and activated macrophages. Optimal protection required both catalases, as the survival of a double mutant lacking both CatB and CatP was lower than that of single-catalase-deficient cells. Although CatB contributed to reactive oxygen species defenses in vitro, CatB was dispensable for lung infection and extrapulmonary dissemination in vivo. Loss of CatB from a strain also lacking superoxide dismutase (Sod3) did not further reduce the survival of Histoplasma yeasts. Nevertheless, some catalase function was required for pathogenesis since simultaneous loss of both CatB and CatP attenuated Histoplasma virulence in vivo. These results demonstrate that Histoplasma's dual catalases comprise a system that enables Histoplasma to efficiently overcome the reactive oxygen produced by the innate immune system.
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26
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Kim JH, Faria NCG, Martins MDL, Chan KL, Campbell BC. Enhancement of antimycotic activity of amphotericin B by targeting the oxidative stress response of Candida and cryptococcus with natural dihydroxybenzaldehydes. Front Microbiol 2012; 3:261. [PMID: 22833742 PMCID: PMC3400132 DOI: 10.3389/fmicb.2012.00261] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 07/03/2012] [Indexed: 11/17/2022] Open
Abstract
In addition to the fungal cellular membrane, the cellular antioxidant system can also be a viable target in the antifungal action of amphotericin B (AMB). Co-application of certain redox-potent natural compounds with AMB actually increases efficacy of the drug through chemosensitization. Some redox-potent chemosensitizers and AMB perturb common cellular targets, resulting in synergistic inhibition of fungal growth. Chemosensitizing activities of four redox-potent benzaldehydes were tested against clinical and reference strains of Candida albicans, C. krusei, C. tropicalis, and Cryptococcus neoformans in combination with AMB, based on assays outlined by the European Committee on Antimicrobial Susceptibility Testing. Two dihydroxybenzaldehydes (DHBAs), i.e., 2,3-DHBA and 2,5-DHBA, significantly enhanced activity of AMB against most strains, as measured by lower minimum inhibitory concentrations and/or minimum fungicidal concentrations (MFCs). A non-hydroxylated benzaldehyde, trans-cinnamaldehyde, showed chemosensitizing activity through lower MFCs, only. Contrastingly, a methoxylated benzaldehyde (3,5-dimethoxybenzaldehyde) had no chemosensitizing activity, as all strains were hypertolerant to this compound. Bioassays using deletion mutants of the model yeast, Saccharomyces cerevisiae, indicated DHBAs exerted their chemosensitizing activity by targeting mitochondrial superoxide dismutase. This targeting, in turn, disrupted the ability of the yeast strains to respond to AMB-induced oxidative stress. These in vitro results indicate that certain DHBAs are potent chemosensitizing agents to AMB through co-disruption of the oxidative stress response capacity of yeasts. Such redox-potent compounds show promise for enhancing AMB-based antifungal therapy for candidiasis and cryptococcosis.
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Affiliation(s)
- Jong H Kim
- Plant Mycotoxin Research Unit, Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture Albany, CA, USA
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27
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Finch J, Arenas R, Baran R. Fungal melanonychia. J Am Acad Dermatol 2012; 66:830-41. [DOI: 10.1016/j.jaad.2010.11.018] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 11/04/2010] [Accepted: 11/11/2010] [Indexed: 01/19/2023]
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28
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Kim JH, Chan KL, Faria NCG, Martins MDL, Campbell BC. Targeting the oxidative stress response system of fungi with redox-potent chemosensitizing agents. Front Microbiol 2012; 3:88. [PMID: 22438852 PMCID: PMC3305922 DOI: 10.3389/fmicb.2012.00088] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Accepted: 02/22/2012] [Indexed: 11/28/2022] Open
Abstract
The cellular antioxidant system is a target in the antifungal action of amphotericin B (AMB) and itraconazole (ITZ), in filamentous fungi. The sakAΔ mutant of Aspergillus fumigatus, a mitogen-activated protein kinase (MAPK) gene deletion mutant in the antioxidant system, was found to be more sensitive to AMB or ITZ than other A. fumigatus strains, a wild type and a mpkCΔ mutant (a MAPK gene deletion mutant in the polyalcohol sugar utilization system). Complete fungal kill (≥99.9%) by ITZ or AMB was also achieved by much lower dosages for the sakAΔ mutant than for the other strains. It appears msnA, an Aspergillus ortholog to Saccharomyces cerevisiaeMSN2 (encoding a stress-responsive C2H2-type zinc-finger regulator) and sakA and/or mpkC (upstream MAPKs) are in the same stress response network under tert-butyl hydroperoxide (t-BuOOH)-, hydrogen peroxide (H2O2)- or AMB-triggered toxicity. Of note is that ITZ-sensitive yeast pathogens were also sensitive to t-BuOOH, showing a connection between ITZ sensitivity and antioxidant capacity of fungi. Enhanced antifungal activity of AMB or ITZ was achieved when these drugs were co-applied with redox-potent natural compounds, 2,3-dihydroxybenzaldehyde, thymol or salicylaldehyde, as chemosensitizing agents. We concluded that redox-potent compounds, which target the antioxidant system in fungi, possess a chemosensitizing capacity to enhance efficacy of conventional drugs.
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Affiliation(s)
- Jong H Kim
- Plant Mycotoxin Research Unit, Western Regional Research Center, USDA-ARS Albany, CA, USA
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Kim JH, Chan KL, Mahoney N, Campbell BC. Antifungal activity of redox-active benzaldehydes that target cellular antioxidation. Ann Clin Microbiol Antimicrob 2011; 10:23. [PMID: 21627838 PMCID: PMC3127747 DOI: 10.1186/1476-0711-10-23] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Accepted: 05/31/2011] [Indexed: 11/10/2022] Open
Abstract
Background Disruption of cellular antioxidation systems should be an effective method for control of fungal pathogens. Such disruption can be achieved with redox-active compounds. Natural phenolic compounds can serve as potent redox cyclers that inhibit microbial growth through destabilization of cellular redox homeostasis and/or antioxidation systems. The aim of this study was to identify benzaldehydes that disrupt the fungal antioxidation system. These compounds could then function as chemosensitizing agents in concert with conventional drugs or fungicides to improve antifungal efficacy. Methods Benzaldehydes were tested as natural antifungal agents against strains of Aspergillus fumigatus, A. flavus, A. terreus and Penicillium expansum, fungi that are causative agents of human invasive aspergillosis and/or are mycotoxigenic. The yeast Saccharomyces cerevisiae was also used as a model system for identifying gene targets of benzaldehydes. The efficacy of screened compounds as effective chemosensitizers or as antifungal agents in formulations was tested with methods outlined by the Clinical Laboratory Standards Institute (CLSI). Results Several benzaldehydes are identified having potent antifungal activity. Structure-activity analysis reveals that antifungal activity increases by the presence of an ortho-hydroxyl group in the aromatic ring. Use of deletion mutants in the oxidative stress-response pathway of S. cerevisiae (sod1Δ, sod2Δ, glr1Δ) and two mitogen-activated protein kinase (MAPK) mutants of A. fumigatus (sakAΔ, mpkCΔ), indicates antifungal activity of the benzaldehydes is through disruption of cellular antioxidation. Certain benzaldehydes, in combination with phenylpyrroles, overcome tolerance of A. fumigatus MAPK mutants to this agent and/or increase sensitivity of fungal pathogens to mitochondrial respiration inhibitory agents. Synergistic chemosensitization greatly lowers minimum inhibitory (MIC) or fungicidal (MFC) concentrations. Effective inhibition of fungal growth can also be achieved using combinations of these benzaldehydes. Conclusions Natural benzaldehydes targeting cellular antioxidation components of fungi, such as superoxide dismutases, glutathione reductase, etc., effectively inhibit fungal growth. They possess antifungal or chemosensitizing capacity to enhance efficacy of conventional antifungal agents. Chemosensitization can reduce costs, abate resistance, and alleviate negative side effects associated with current antifungal treatments.
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Affiliation(s)
- Jong H Kim
- Plant Mycotoxin Research Unit, Western Regional Research Center, USDA-ARS, 800 Buchanan St,, Albany, CA 94710, USA
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Ptilomycalin A inhibits laccase and melanization in Cryptococcus neoformans. Bioorg Med Chem 2011; 19:6654-7. [PMID: 21715177 DOI: 10.1016/j.bmc.2011.05.041] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 04/23/2011] [Accepted: 05/23/2011] [Indexed: 11/22/2022]
Abstract
The antifungal spirocyclic guanidine alkaloid, ptilomycalin A, from marine sponge Monanchora arbuscula, inhibits melanogenesis of Cryptococcus neoformans in vitro through inhibition of biosynthesis of laccase in the melanin biosynthetic pathway with an IC(50) of 7.3 μM.
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Chemosensitization of aflatoxigenic fungi to antimycin A and strobilurin using salicylaldehyde, a volatile natural compound targeting cellular antioxidation system. Mycopathologia 2010; 171:291-8. [PMID: 20803256 DOI: 10.1007/s11046-010-9356-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Accepted: 08/05/2010] [Indexed: 10/19/2022]
Abstract
Various species of fungi in the genus Aspergillus are the most common causative agents of invasive aspergillosis and/or producers of hepato-carcinogenic mycotoxins. Salicylaldehyde (SA), a volatile natural compound, exhibited potent antifungal and anti-mycotoxigenic activities to A. flavus and A. parasiticus. By exposure to the volatilized SA, the growth of A. parasiticus was inhibited up to 10-75% at 9.5 mM ≤ SA ≤ 16.0 mM, while complete growth inhibition was achieved at 19.0 mM ≤ SA. Similar trends were also observed with A. flavus. The aflatoxin production, i.e., aflatoxin B(1) and B(2) (AFB(1), AFB(2)) for A. flavus and AFB(1), AFB(2), AFG(1), and AFG(2) for A. parasiticus, in the SA-treated (9.5 mM) fungi was reduced by ~13-45% compared with the untreated control. Using gene deletion mutants of the model yeast Saccharomyces cerevisiae, we identified the fungal antioxidation system as the molecular target of SA, where sod1Δ [cytosolic superoxide dismutase (SOD)], sod2Δ (mitochondrial SOD), and glr1Δ (glutathione reductase) mutants showed increased sensitivity to this compound. Also sensitive was the gene deletion mutant, vph2Δ, for the vacuolar ATPase assembly protein, suggesting vacuolar detoxification plays an important role for fungal tolerance to SA. In chemosensitization experiments, co-application of SA with either antimycin A or strobilurin (inhibitors of mitochondrial respiration) resulted in complete growth inhibition of Aspergillus at much lower dose treatment of either agent, alone. Therefore, SA can enhance antifungal activity of commercial antifungal agents required to achieve effective control. SA is a potent antifungal and anti-aflatoxigenic volatile that may have some practical application as a fumigant.
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Cunha MML, Franzen AJ, Seabra SH, Herbst MH, Vugman NV, Borba LP, de Souza W, Rozental S. Melanin in Fonsecaea pedrosoi: a trap for oxidative radicals. BMC Microbiol 2010; 10:80. [PMID: 20233438 PMCID: PMC2845570 DOI: 10.1186/1471-2180-10-80] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Accepted: 03/16/2010] [Indexed: 11/10/2022] Open
Abstract
Background The pathogenic fungus Fonsecaea pedrosoi constitutively produces the pigment melanin, an important virulence factor in fungi. Melanin is incorporated in the cell wall structure and provides chemical and physical protection for the fungus. We evaluated the production of nitric oxide (NO) in macrophages, the oxidative burst and the inducible nitric oxide synthase (i-NOS) activity in interactions between activated murine macrophages and F. pedrosoi. Experiments were carried out with or without tricyclazole (TC) treatment, a selective inhibitor of the dihydroxynaphthalene (DHN)-melanin biosynthesis pathway in F. pedrosoi. The paramagnetisms of melanin and the TC-melanin were analysed by electron spin resonance. The fungal growth responses to H2O2 and to S-nitroso-N-acetylpenicillamine (SNAP), a nitric oxide donor, were also evaluated. Results Melanised F. pedrosoi cells were more resistant to both H2O2 and NO. Nitrite was not detected in the supernatant of macrophages incubated with melanised fungal cells. However, i-NOS expression was unaffected by the presence of either untreated control F. pedrosoi or TC-treated F. pedrosoi. In addition, the inhibition of the DHN-melanin pathway by TC improved the oxidative burst capability of the macrophages. Conclusion The NO-trapping ability of F. pedrosoi melanin is an important mechanism to escape the oxidative burst of macrophages.
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Affiliation(s)
- Marcel M L Cunha
- Instituto de Biofísica Carlos Chagas Filho, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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Leventakos K, Ben-Ami R, Lewis RE, Kontoyiannis DP. Immunomodulating effects of antifungal therapy. CURRENT FUNGAL INFECTION REPORTS 2009. [DOI: 10.1007/s12281-009-0034-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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The innate immune response to Aspergillus fumigatus. Microbes Infect 2009; 11:919-27. [DOI: 10.1016/j.micinf.2009.07.002] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Accepted: 07/08/2009] [Indexed: 01/26/2023]
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Allicin enhances the oxidative damage effect of amphotericin B against Candida albicans. Int J Antimicrob Agents 2009; 33:258-63. [DOI: 10.1016/j.ijantimicag.2008.09.014] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Revised: 09/03/2008] [Accepted: 09/18/2008] [Indexed: 11/20/2022]
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Santos ALS, Bittencourt VCB, Pinto MR, Silva BA, Barreto-Bergter E. Biochemical characterization of potential virulence markers in the human fungal pathogen Pseudallescheria boydii. Med Mycol 2009; 47:375-86. [PMID: 19235547 DOI: 10.1080/13693780802610305] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The ubiquitous Pseudallescheria boydii (anamorph Scedosporium apiospermum) is a saprophytic filamentous fungus recognized as a potent etiologic agent of a wide variety of infections in immunocompromised as well as in immunocompetent patients. Very little is known about the virulence factors expressed by this fungal pathogen. The present review provides an overview of recent discoveries related to the identification and biochemical characterization of potential virulence attributes produced by P. boydii, with special emphasis on surface and released molecules. These structures include polysaccharides (glucans), glycopeptides (peptidorhamnomannans), glycolipids (glucosylceramides) and hydrolytic enzymes (proteases, phosphatases and superoxide dismutase), which have been implicated in some fundamental cellular processes in P. boydii including growth, differentiation and interaction with host molecules. Elucidation of the structure of cell surface components as well as the secreted molecules, especially those that function as virulence determinants, is of great relevance to understand the pathogenic mechanisms of P. boydii.
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Affiliation(s)
- André L S Santos
- Laboratorio de Estudos Integrados em Bioquimica Microbiana, Departamento de Microbiologia Geral/IMPPG, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Rio de Janeiro, RJ, Brazil
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Ingavale SS, Chang YC, Lee H, McClelland CM, Leong ML, Kwon-Chung KJ. Importance of mitochondria in survival of Cryptococcus neoformans under low oxygen conditions and tolerance to cobalt chloride. PLoS Pathog 2008; 4:e1000155. [PMID: 18802457 PMCID: PMC2528940 DOI: 10.1371/journal.ppat.1000155] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Accepted: 08/14/2008] [Indexed: 01/09/2023] Open
Abstract
Cryptococcus neoformans is an environmental fungal pathogen that requires atmospheric levels of oxygen for optimal growth. For the fungus to be able to establish an infection, it must adapt to the low oxygen concentrations in the host environment compared to its natural habitat. In order to investigate the oxygen sensing mechanism in C. neoformans, we screened T-DNA insertional mutants for hypoxia-mimetic cobalt chloride (CoCl2)-sensitive mutants. All the CoCl2-sensitive mutants had a growth defect under low oxygen conditions at 37°C. The majority of mutants are compromised in their mitochondrial function, which is reflected by their reduced rate of respiration. Some of the mutants are also defective in mitochondrial membrane permeability, suggesting the importance of an intact respiratory system for survival under both high concentrations of CoCl2 as well as low oxygen conditions. In addition, the mutants tend to accumulate intracellular reactive oxygen species (ROS), and all mutants show sensitivity to various ROS generating chemicals. Gene expression analysis revealed the involvement of several pathways in response to cobalt chloride. Our findings indicate cobalt chloride sensitivity and/or sensitivity to low oxygen conditions are linked to mitochondrial function, sterol and iron homeostasis, ubiquitination, and the ability of cells to respond to ROS. These findings imply that multiple pathways are involved in oxygen sensing in C. neoformans. Cryptococcus neoformans is an obligate aerobic fungus that requires atmospheric levels of oxygen (21%) for optimal growth. However, the fungus is able to cause life-threatening brain infections in humans, where the oxygen tension is significantly lower than 21%. To understand the pathobiology of Cryptococcus neoformans, it is important to explore the molecular mechanisms adopted by the fungus to survive under low oxygen conditions. By using cobalt chloride, a hypoxia-mimicking agent, we isolated a number of mutants that are unable to grow in the presence of 0.7 mM CoCl2 as well as at low oxygen conditions. In this study, we show that mitochondria play an important role for C. neoformans to survive in low oxygen conditions. We demonstrate that mutants harboring mutations in the genes related to mitochondrial functions have mitochondrial membrane permeability defect and lowered respiration rate and are more sensitive to stress generating chemicals, in addition to their inability to survive at low oxygen conditions. Finally, we also show that when wild-type cells are exposed to hypoxia-mimicking cobalt chloride, expression of genes involved in respiration and iron and sterol homeostasis, as well as ubiquitination, changes significantly.
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Affiliation(s)
- Susham S. Ingavale
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Yun C. Chang
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Hyeseung Lee
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Carol M. McClelland
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Madeline L. Leong
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Kyung J. Kwon-Chung
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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Ben‐Ami R, Lewis R, Kontoyiannis D. Immunocompromised Hosts: Immunopharmacology of Modern Antifungals. Clin Infect Dis 2008; 47:226-35. [DOI: 10.1086/589290] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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Kim JH, Mahoney N, Chan KL, Molyneux RJ, May GS, Campbell BC. Chemosensitization of fungal pathogens to antimicrobial agents using benzo analogs. FEMS Microbiol Lett 2008; 281:64-72. [DOI: 10.1111/j.1574-6968.2008.01072.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Li Q, McNeil B, Harvey LM. Adaptive response to oxidative stress in the filamentous fungus Aspergillus niger B1-D. Free Radic Biol Med 2008; 44:394-402. [PMID: 17967428 DOI: 10.1016/j.freeradbiomed.2007.09.019] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Revised: 09/03/2007] [Accepted: 09/29/2007] [Indexed: 10/22/2022]
Abstract
In the present study, we used a recombinant filamentous fungus strain, Aspergillus niger B1-D, as a model system, and investigated the antioxidant defences in this organism. Our findings indicate that pretreatment with low concentrations of H(2)O(2) completely prevents killing by this oxidant at high concentrations. It shows that A. niger adapts to exposure to H(2)O(2) by reducing growth and inducing a number of antioxidant enzyme activities, including superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, of which the induction of catalase is the most pronounced. Moreover the decline of these antioxidant enzymes activities after H(2)O(2) detoxification, coincides with recommencement of growth. Results from monitoring the extracellular H(2)O(2) concentration clearly indicate a very rapid detoxification rate for H(2)O(2) in adapted A. niger cultures. A mathematical model predicts only very low concentrations of intracellular H(2)O(2) accumulating in such cultures. Our results also show that glutathione plays a role in the oxidative defence against H(2)O(2) in A. niger. On addition of H(2)O(2), the intracellular pool of glutathione increases while the redox state of glutathione becomes more oxidized.
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Affiliation(s)
- Qiang Li
- Strathclyde Fermentation Centre, Strathclyde Institute of Pharmacy and Biomedical Sciences, Royal College Building, University of Strathclyde, Glasgow, UK
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Capilla J, Clemons KV, Stevens DA. Animal models: an important tool in mycology. Med Mycol 2007; 45:657-84. [PMID: 18027253 PMCID: PMC7107685 DOI: 10.1080/13693780701644140] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Accepted: 08/22/2007] [Indexed: 10/29/2022] Open
Abstract
Animal models of fungal infections are, and will remain, a key tool in the advancement of the medical mycology. Many different types of animal models of fungal infection have been developed, with murine models the most frequently used, for studies of pathogenesis, virulence, immunology, diagnosis, and therapy. The ability to control numerous variables in performing the model allows us to mimic human disease states and quantitatively monitor the course of the disease. However, no single model can answer all questions and different animal species or different routes of infection can show somewhat different results. Thus, the choice of which animal model to use must be made carefully, addressing issues of the type of human disease to mimic, the parameters to follow and collection of the appropriate data to answer those questions being asked. This review addresses a variety of uses for animal models in medical mycology. It focuses on the most clinically important diseases affecting humans and cites various examples of the different types of studies that have been performed. Overall, animal models of fungal infection will continue to be valuable tools in addressing questions concerning fungal infections and contribute to our deeper understanding of how these infections occur, progress and can be controlled and eliminated.
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Affiliation(s)
- Javier Capilla
- California Institute for Medical Research, San Jose, USA
- Department of Medicine, Division of Infectious Diseases, Santa Clara Valley Medical Center, San Jose, USA
- Department of Medicine, Division of Infectious Diseases and Geographic Medicine, Stanford University, Stanford, California, USA
| | - Karl V. Clemons
- California Institute for Medical Research, San Jose, USA
- Department of Medicine, Division of Infectious Diseases, Santa Clara Valley Medical Center, San Jose, USA
- Department of Medicine, Division of Infectious Diseases and Geographic Medicine, Stanford University, Stanford, California, USA
| | - David A. Stevens
- California Institute for Medical Research, San Jose, USA
- Department of Medicine, Division of Infectious Diseases, Santa Clara Valley Medical Center, San Jose, USA
- Department of Medicine, Division of Infectious Diseases and Geographic Medicine, Stanford University, Stanford, California, USA
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Baeza LC, Bailão AM, Borges CL, Pereira M, Soares CMDA, Mendes Giannini MJS. cDNA representational difference analysis used in the identification of genes expressed by Trichophyton rubrum during contact with keratin. Microbes Infect 2007; 9:1415-21. [PMID: 17905626 DOI: 10.1016/j.micinf.2007.07.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2006] [Revised: 07/11/2007] [Accepted: 07/12/2007] [Indexed: 10/23/2022]
Abstract
Dermatophytes are adapted to infect skin, hair and nails by their ability to utilize keratin as a nutrient source. Trichophyton rubrum is an anthropophilic fungus, causing up to 90% of chronic cases of dermatophytosis. The understanding of the complex interactions between the fungus and its host should include the identification of genes expressed during infection. To identify the genes involved in the infection process, representational difference analysis (RDA) was applied to two cDNA populations from T. rubrum, one transcribed from the RNA of fungus cultured in the presence of keratin and the other from RNA generated during fungal growth in minimal medium. The analysis identified differentially expressed transcripts. Genes related to signal transduction, membrane protein, oxidative stress response, and some putative virulence factors were up-regulated during the contact of the fungus with keratin. The expression patterns of these genes were also verified by real-time PCR, in conidia of T. rubrum infecting primarily cultured human keratinocytes in vitro, revealing their potential role in the infective process. A better understanding of this interaction will contribute significantly to our knowledge of the process of dermatophyte infection.
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Affiliation(s)
- Lilian Cristiane Baeza
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, UNESP, CEP 14801-902, 1621 Araraquara, SP, Brazil
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Martínez-Esparza M, Aguinaga A, González-Párraga P, García-Peñarrubia P, Jouault T, Argüelles JC. Role of trehalose in resistance to macrophage killing: study with a tps1/tps1 trehalose-deficient mutant of Candida albicans. Clin Microbiol Infect 2007; 13:384-94. [PMID: 17359322 DOI: 10.1111/j.1469-0691.2007.01663.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Accumulation of trehalose by yeast is an important protective mechanism against different stress conditions. This study examined the effect of trehalose on several growth features, as well as its association with the intracellular survival of yeasts exposed to macrophages. A tps1/tps1 mutant and its parental counterpart, CAI4, exhibited similar growth rates and preserved their dimorphic conversion and agglutination ability. However, electron-microscopy of cell-wall architecture showed a partial loss of material from the outer cell-wall layer in the tps1/tps1 mutant. Flow-cytometry revealed that the mutant had lower auto-fluorescence levels and a higher fluorescein isothiocynate staining efficiency. When co-cultured with macrophages, a slight reduction in binding to macrophages and slower ingestion kinetics were revealed for the tps1/tps1 mutant, but these did not interfere significantly with the amount of yeast ingested by macrophages after co-incubation for 2 h. Under the same conditions, CAI4 cells were more resistant to macrophage killing than was the tps1 null mutant, provided that the macrophages had been stimulated previously with interferon-gamma. Measurement of trehalose content and the anti-oxidant activities of yeast cells recovered after phagocytosis revealed that the trehalose content and the glutathione reductase activity were increased only in CAI4 cells, whereas levels of catalase activity were increased similarly in both strains. These results suggest that the presence of trehalose in Candida albicans is a contributory factor that protects the cell from injury caused by macrophages.
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Affiliation(s)
- M Martínez-Esparza
- Department of Biochemistry, Molecular Biology (B) and Immunology, Medical School, University of Murcia, Murcia, Spain.
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Lunetta JM, Simmons KA, Johnson SM, Pappagianis D. Molecular Cloning and Expression of a cDNA Encoding a Coccidioides posadasii Cu,Zn Superoxide Dismutase Identified by Proteomic Analysis of the Coccidioidal T27K Vaccine. Ann N Y Acad Sci 2007; 1111:181-97. [PMID: 17344523 DOI: 10.1196/annals.1406.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Previous studies have demonstrated that the coccidioidal T27K vaccine preparation is protective in mice against respiratory challenge using Coccidioides posadasii (C. posadasii) arthroconidia. Proteomic methods have been employed to define the molecular components within the vaccine. This method has led to the identification of novel and previously uncharacterized coccidioidal proteins including a Cu,Zn superoxide dismutase. A two-dimensional gel of the T27K vaccine was run and spots were excised for mass spectrometric analysis. One peptide was obtained from the T27K gel that matched a TIGR C. posadasii 2.0 gene index tentative consensus sequence, TC1072, which is similar to fungal Cu,Zn superoxide dismutase. Activity assays performed with native PAGE gels of the T27K vaccine showed that the vaccine contains superoxide dismutase. The cDNA encoding the enzyme has been cloned and sequenced and expressed as a recombinant protein.
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Affiliation(s)
- Jennine M Lunetta
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, California 95616, USA.
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Shibuya K, Paris S, Ando T, Nakayama H, Hatori T, Latgé JP. Catalases of Aspergillus fumigatus and inflammation in aspergillosis. ACTA ACUST UNITED AC 2007; 47:249-55. [PMID: 17086155 DOI: 10.3314/jjmm.47.249] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The article describes various features of aspergillosis and a discussed the role of calatases produced by Aspergillus fumigatus during infection. Since a large body of invasive Aspergillus infection occurs as an opportunistic infection in variously impaired defense mechanisms, there is a wide spectrum of histopathological features of lesions demonstrated at the site of infection. Accordingly, histopathology of the lesions can be understood as a phenotypical representation of interaction between differently impaired functions of neutrophils and macrophages and virulence factors of invading Aspergilli. Consideration of previous pathological knowledge regarding infection and inflammation provides much important information to predict the pathophysiology of a patient. Meanwhile, detoxification of hydrogen peroxide by catalases has been proposed as a way to overcome this host response. A. fumigatus produces three active catalases, one from conidia and two from mycelia. CatAp, a spore specific monofunctional catalase, is resistant to heat and metal ions. In spite of their increased sensitivity to H(2)O(2), killing of catA conidia by alveolar macrophages, virulence in animals was similar to wild type conidia. In contrast to mycelial Cat1p, and CatAp catalases, the mycelial Cat2p is a bifunctional catalase-peroxidase enzyme and is also sensitive to heat, metal ions and detergent. Surprisingly, the mycelium of the double cat1 cat2 mutant with no catalase activity has only a slightly increased sensitivity to H(2)O(2) and was as sensitive to the killing of polymorphonuclear neutrophils as the wild type strain. However, it showed a delayed infection in the rat model of aspergillosis compared to the wild type strain. Consequently, it should be emphasized that conidial catalase is not a virulence factor but that mycelial catalases transiently protect the fungus from the host defence reactions.
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Affiliation(s)
- Kazutoshi Shibuya
- Department of Surgical Pathology, Toho University School of Medicine, Tokyo, Japan
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Rosa DD, Campos MA, Targon MLP, Souza AA. Phytophthora parasitica transcriptome, a new concept in the understanding of the citrus gummosis. Genet Mol Biol 2007. [DOI: 10.1590/s1415-47572007000500028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Kim JH, Campbell BC, Mahoney N, Chan KL, May GS. Targeting antioxidative signal transduction and stress response system: control of pathogenic Aspergillus with phenolics that inhibit mitochondrial function. J Appl Microbiol 2006; 101:181-9. [PMID: 16834605 DOI: 10.1111/j.1365-2672.2006.02882.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS The aim of this study was to show whether antioxidative response systems are potentially useful molecular targets for control of Aspergillus fumigatus and Aspergillus flavus. Selected phenolic agents are used in target-gene-based bioassays to determine their impact on mitochondrial respiration. METHODS AND RESULTS Vanillyl acetone, vanillic acid, vanillin, cinnamic acid, veratraldehyde, m-coumaric acid (phenolic agents to which Saccharomyces cerevisiae sod2delta mutant showed sensitivity), carboxin (inhibits complex II of the mitochondrial respiratory chain), strobilurins/antimycin A (inhibits complex III of the mitochondrial respiratory chain) and fludioxonil/fenpiclonil [antifungals potentiated by mitogen-activated protein kinase (MAPK)] were examined in A. fumigatus, A. flavus and S. cerevisiae. Individual or combined application of phenolics with inhibitors of mitochondrial respiration showed some of the phenolics effectively inhibited fungal growth. Target-gene bioassays were performed using a sakAdelta (MAPK deletion) strain of A. fumigatus and a complementation analysis using the mitochondrial superoxide dismutase (Mn-SOD) gene (sodA) of A. flavus in the ortholog mutant, sod2delta, of S. cerevisiae. The results demonstrated that mitochondrial antioxidative stress system plays important roles in fungal response to antifungal agents tested. CONCLUSIONS Antioxidative response systems of fungi can be an efficient molecular target of phenolics for pathogen control. Combined application of phenolics with inhibitors of mitochondrial respiration can effectively suppress the growth of fungi. SIGNIFICANCE AND IMPACT OF THE STUDY Natural compounds that do not pose any significant medical or environmental risks could serve as useful alternatives or additives to conventional antifungals. Identifying the antioxidative response systems in other pathogens could improve methods for fungal control.
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Affiliation(s)
- J H Kim
- Plant Mycotoxin Research Unit, Western Regional Research Center, USDA-ARS, Albany, CA 94710, USA
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Kim JH, Mahoney N, Chan KL, Molyneux RJ, Campbell BC. Controlling food-contaminating fungi by targeting their antioxidative stress-response system with natural phenolic compounds. Appl Microbiol Biotechnol 2006; 70:735-9. [PMID: 16463173 DOI: 10.1007/s00253-005-0123-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2005] [Revised: 07/21/2005] [Accepted: 07/24/2005] [Indexed: 10/25/2022]
Abstract
The antioxidative stress-response system is essential to fungi for tolerating exposure to phenolic compounds. We show how this system can be targeted to improve fungal control by using compounds that inhibit the fungal mitochondrial respiratory chain. Targeting mitochondrial superoxide dismutase with selected phenolic acid derivatives (e.g., vanillyl acetone) resulted in a 100- to 1,000-fold greater sensitivity to strobilurin or carboxin fungicides. This synergism is significantly greater with strobilurin than with carboxin, suggesting that complex III of the mitochondrial respiratory chain is a better target than complex II for fungal control, using phenolics. These results show certain natural compounds are effective synergists to commercial fungicides and can be used for improving control of food-contaminating pathogens. These results suggest that the use of such compounds for fungal control can reduce environmental and health risks associated with commercial fungicides, lower cost for control, and the probability for development of resistance.
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Affiliation(s)
- Jong H Kim
- Plant Mycotoxin Research Unit, Western Regional Research Center, USDA-ARS, 800 Buchanan St., Albany, CA 94710, USA
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Pastor A, Gafa V, Boutonnat J, Grillot R, Ambroise-Thomas P, Aldebert D. Intracellular oxidative response of human monocytes and granulocytes to different strains of Aspergillus fumigatus. Mycoses 2006; 49:73-9. [PMID: 16466437 DOI: 10.1111/j.1439-0507.2006.01188.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Aspergillus fumigatus is one of the most prevalent airborne fungal pathogens, causing severe and often fatal infections. Its fungal virulence factors have not been clearly identified. Reactive oxygen species produced by phagocytic cells are potent fungicides for A. fumigatus. The aim of this study was to examine the influence of conidia pigmentation, fungal development stage and genotype strain on human leucocytes oxidative response. Various A. fumigatus strains were used and the oxidative response was analysed by flow cytometry. A significant difference was observed between live- and killed-conidia. A pigmentless strain gave an important intracellular oxidative response compared with pigmented strains. But no difference was observed between strains isolated from patients with invasive aspergillosis (IA) and bronchial colonisation. The modification of healthy phagocytes' oxidative response caused by A. fumigatus components is not sufficient to explain the virulence of fungus and to predict an evolution of patients with IA.
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Affiliation(s)
- Alexandrine Pastor
- Interactions Cellulaires Parasite-Hôte (EA.UJF 2940), Université Joseph Fourier Grenoble I, Faculté de Médecine-Pharmacie, Domaine de la Merci, La Tronche, France
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50
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Westwater C, Balish E, Schofield DA. Candida albicans-conditioned medium protects yeast cells from oxidative stress: a possible link between quorum sensing and oxidative stress resistance. EUKARYOTIC CELL 2005; 4:1654-61. [PMID: 16215173 PMCID: PMC1265892 DOI: 10.1128/ec.4.10.1654-1661.2005] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Candida albicans, the most frequent fungal pathogen of humans, encounters high levels of oxidants following ingestion by professional phagocytes and through contact with hydrogen peroxide-producing bacteria. In this study, we provide evidence that C. albicans is able to coordinately regulate the oxidative stress response at the global cell population level by releasing protective molecules into the surrounding medium. We demonstrate that conditioned medium, which is defined as a filter-sterilized supernatant from a C. albicans stationary-phase culture, is able to protect yeast cells from both hydrogen peroxide and superoxide anion-generating agents. Exponential-phase yeast cells preexposed to conditioned medium were able to survive levels of oxidative stress that would normally kill actively growing yeast cells. Heat treatment, digestion with proteinase K, pH adjustment, or the addition of the oxidant scavenger alpha-tocopherol did not alter the ability of conditioned medium to induce a protective response. Farnesol, a heat-stable quorum-sensing molecule (QSM) that is insensitive to proteolytic enzymes and is unaffected by pH extremes, is partly responsible for this protective response. In contrast, the QSM tyrosol did not alter the sensitivity of C. albicans cells to oxidants. Relative reverse transcription-PCR analysis indicates that Candida-conditioned growth medium induces the expression of CAT1, SOD1, SOD2, and SOD4, suggesting that protection may be mediated through the transcriptional regulation of antioxidant-encoding genes. Together, these data suggest a link between the quorum-sensing molecule farnesol and the oxidative stress response in C. albicans.
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Affiliation(s)
- Caroline Westwater
- Center for Oral Health Research, Department of Stomatology, Medical University of South Carolina, Charleston, USA.
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