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Xiao Y, Zhang S, Li H, Teng K, Wu S, Liu Y, Yu F, He Z, Li L, Li L, Meng D, Yin H, Wang Y. Metagenomic insights into the response of soil microbial communities to pathogenic Ralstonia solanacearum. FRONTIERS IN PLANT SCIENCE 2024; 15:1325141. [PMID: 38434434 PMCID: PMC10904623 DOI: 10.3389/fpls.2024.1325141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 01/17/2024] [Indexed: 03/05/2024]
Abstract
Understanding the response of soil microbial communities to pathogenic Ralstonia solanacearum is crucial for preventing bacterial wilt outbreaks. In this study, we investigated the soil physicochemical and microbial community to assess their impact on the pathogenic R.solanacearum through metagenomics. Our results revealed that certain archaeal taxa were the main contributors influencing the health of plants. Additionally, the presence of the pathogen showed a strong negative correlation with soil phosphorus levels, while soil phosphorus was significantly correlated with bacterial and archaeal communities. We found that the network of microbial interactions in healthy plant rhizosphere soils was more complex compared to diseased soils. The diseased soil network had more linkages, particularly related to the pathogen occurrence. Within the network, the family Comamonadaceae, specifically Ramlibacter_tataouinensis, was enriched in healthy samples and showed a significantly negative correlation with the pathogen. In terms of archaea, Halorubrum, Halorussus_halophilus (family: Halobacteriaceae), and Natronomonas_pharaonis (family: Haloarculaceae) were enriched in healthy plant rhizosphere soils and showed negative correlations with R.solanacearum. These findings suggested that the presence of these archaea may potentially reduce the occurrence of bacterial wilt disease. On the other hand, Halostagnicola_larseniia and Haloterrigena_sp._BND6 (family: Natrialbaceae) had higher relative abundance in diseased plants and exhibited significantly positive correlations with R.solanacearum, indicating their potential contribution to the pathogen's occurrence. Moreover, we explored the possibility of functional gene sharing among the correlating bacterial pairs within the Molecular Ecological Network. Our analysis revealed 468 entries of horizontal gene transfer (HGT) events, emphasizing the significance of HGT in shaping the adaptive traits of plant-associated bacteria, particularly in relation to host colonization and pathogenicity. Overall, this work revealed key factors, patterns and response mechanisms underlying the rhizosphere soil microbial populations. The findings offer valuable guidance for effectively controlling soil-borne bacterial diseases and developing sustainable agriculture practices.
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Affiliation(s)
- Yansong Xiao
- Chenzhou Tobacco Company of Hunan Province, Changsha, China
| | - Sai Zhang
- Chenzhou Tobacco Company of Hunan Province, Changsha, China
| | - Hongguang Li
- Chenzhou Tobacco Company of Hunan Province, Changsha, China
| | - Kai Teng
- Xiangxi Tobacco Co Hunan Prov, Changsha, China
| | - Shaolong Wu
- Hunan Tobacco Research Institute, Changsha, China
| | - Yongbin Liu
- Chenzhou Tobacco Company of Hunan Province, Changsha, China
| | - Fahui Yu
- Chenzhou Tobacco Company of Hunan Province, Changsha, China
| | - Zhihong He
- Chenzhou Tobacco Company of Hunan Province, Changsha, China
| | - Lijuan Li
- Chenzhou Tobacco Company of Hunan Province, Changsha, China
| | - Liangzhi Li
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
| | - Delong Meng
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
| | - Huaqun Yin
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
| | - Yujie Wang
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
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Assa D, Voorhies M, Sil A. Chemical stimuli override a temperature-dependent morphological program by reprogramming the transcriptome of a fungal pathogen. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.21.537729. [PMID: 37131633 PMCID: PMC10153268 DOI: 10.1101/2023.04.21.537729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The human fungal pathogen Histoplasma changes its morphology in response to temperature. At 37°C it grows as a budding yeast whereas at room temperature it transitions to hyphal growth. Prior work has demonstrated that 15-20% of transcripts are temperature-regulated, and that transcription factors Ryp1-4 are necessary to establish yeast growth. However, little is known about transcriptional regulators of the hyphal program. To identify TFs that regulate filamentation, we utilize chemical inducers of hyphal growth. We show that addition of cAMP analogs or an inhibitor of cAMP breakdown overrides yeast morphology, yielding inappropriate hyphal growth at 37°C. Additionally, butyrate supplementation triggers hyphal growth at 37°C. Transcriptional profiling of cultures filamenting in response to cAMP or butyrate reveals that a limited set of genes respond to cAMP while butyrate dysregulates a larger set. Comparison of these profiles to previous temperature- or morphology-regulated gene sets identifies a small set of morphology-specific transcripts. This set contains 9 TFs of which we characterized three, STU1 , FBC1 , and PAC2 , whose orthologs regulate development in other fungi. We found that each of these TFs is individually dispensable for room-temperature (RT) induced filamentation but each is required for other aspects of RT development. FBC1 and PAC2 , but not STU1 , are necessary for filamentation in response to cAMP at 37°C. Ectopic expression of each of these TFs is sufficient to induce filamentation at 37°C. Finally, PAC2 induction of filamentation at 37°C is dependent on STU1 , suggesting these TFs form a regulatory circuit that, when activated at RT, promotes the hyphal program. Importance Fungal illnesses pose a significant disease burden. However, the regulatory circuits that govern the development and virulence of fungi remain largely unknown. This study utilizes chemicals that can override the normal growth morphology of the human pathogen Histoplasma . Using transcriptomic approaches, we identify novel regulators of hyphal morphology and refine our understanding of the transcriptional circuits governing morphology in Histoplasma .
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Vargas-Maya NI, Olmedo-Monfil V, Ramírez-Prado JH, Reyes-Cortés R, Padilla-Vaca F, Franco B. Catalases in the pathogenesis of Sporothrix schenckii research. PeerJ 2022; 10:e14478. [PMID: 36523453 PMCID: PMC9745942 DOI: 10.7717/peerj.14478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 11/07/2022] [Indexed: 12/12/2022] Open
Abstract
Pathogenic fungal infection success depends on the ability to escape the immune response. Most strategies for fungal infection control are focused on the inhibition of virulence factors and increasing the effectiveness of antifungal drugs. Nevertheless, little attention has been focused on their physiological resistance to the host immune system. Hints may be found in pathogenic fungi that also inhabit the soil. In nature, the saprophyte lifestyle of fungi is also associated with predators that can induce oxidative stress upon cell damage. The natural sources of nutrients for fungi are linked to cellulose degradation, which in turn generates reactive oxygen species (ROS). Overall, the antioxidant arsenal needed to thrive both in free-living and pathogenic lifestyles in fungi is fundamental for success. In this review, we present recent findings regarding catalases and oxidative stress in fungi and how these can be in close relationship with pathogenesis. Additionally, special focus is placed on catalases of Sporothrix schenckii as a pathogenic model with a dual lifestyle. It is assumed that catalase expression is activated upon exposure to H2O2, but there are reports where this is not always the case. Additionally, it may be relevant to consider the role of catalases in S. schenckii survival in the saprophytic lifestyle and why their study can assess their involvement in the survival and therefore, in the virulence phenotype of different species of Sporothrix and when each of the three catalases are required. Also, studying antioxidant mechanisms in other isolates of pathogenic and free-living fungi may be linked to the virulence phenotype and be potential therapeutic and diagnostic targets. Thus, the rationale for this review to place focus on fungal catalases and their role in pathogenesis in addition to counteracting the effect of immune system reactive oxygen species. Fungi that thrive in soil and have mammal hosts could shed light on the importance of these enzymes in the two types of lifestyles. We look forward to encouraging more research in a myriad of areas on catalase biology with a focus on basic and applied objectives and placing these enzymes as virulence determinants.
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Affiliation(s)
| | | | | | - Ruth Reyes-Cortés
- Biology Department, Universidad de Guanajuato, Guanajuato, Guanajuato, México
| | - Felipe Padilla-Vaca
- Biology Department, Universidad de Guanajuato, Guanajuato, Guanajuato, México
| | - Bernardo Franco
- Biology Department, Universidad de Guanajuato, Guanajuato, Guanajuato, México
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4
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Enzyme activity and expression of catalases in response to oxidative stress in Sporothrix schenckii. Microb Pathog 2021; 161:105270. [PMID: 34793878 DOI: 10.1016/j.micpath.2021.105270] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 09/27/2021] [Accepted: 10/25/2021] [Indexed: 10/19/2022]
Abstract
Sporothrix schenckii is a dimorphic fungus, pathogenic to humans and animals, which is usually infective in the yeast form. Reactive oxygen species (ROS) play an important role in the host's defense, damaging the pathogen's DNA, proteins, and lipids. To prevent oxidative damage, the ROS are detoxified by pathogen-derived antioxidant enzymes such as catalases (CATs). In this work, we analyzed the activity and expression level of three S. schenckii genes, designated as CAT1, CAT2, and CAT3, that putatively encoded for three isoforms of monofunctional CAT with a predicted molecular weight of 57.6, 56.2, and 81.4 kDa, respectively. Our results demonstrate that oxidative stress induced by exogenous H2O2 leads to an altered lipid peroxidation, modifying CAT activity and the expression levels of the CAT genes, being CAT1 and CAT3 the genes with the highest expression in response to the oxidizing agent. These results show that CAT isoforms in S. schenckii can be regulated in response to oxidative stress and might help to control ROS homeostasis in the fungus-host interaction.
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Blancett LT, Runge KA, Reyes GM, Kennedy LA, Jackson SC, Scheuermann SE, Harmon MB, Williams JC, Shearer G. Deletion of the Stress Response Gene DDR48 from Histoplasma capsulatum Increases Sensitivity to Oxidative Stress, Increases Susceptibility to Antifungals, and Decreases Fitness in Macrophages. J Fungi (Basel) 2021; 7:981. [PMID: 34829268 PMCID: PMC8617954 DOI: 10.3390/jof7110981] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/15/2021] [Accepted: 11/16/2021] [Indexed: 11/21/2022] Open
Abstract
The stress response gene DDR48 has been characterized in Saccharomyces cerevisiae and Candida albicans to be involved in combating various cellular stressors, from oxidative agents to antifungal compounds. Surprisingly, the biological function of DDR48 has yet to be identified, though it is likely an important part of the stress response. To gain insight into its function, we characterized DDR48 in the dimorphic fungal pathogen Histoplasma capsulatum. Transcriptional analyses showed preferential expression of DDR48 in the mycelial phase. Induction of DDR48 in Histoplasma yeasts developed after treatment with various cellular stress compounds. We generated a ddr48∆ deletion mutant to further characterize DDR48 function. Loss of DDR48 alters the transcriptional profile of the oxidative stress response and membrane synthesis pathways. Treatment with ROS or antifungal compounds reduced survival of ddr48∆ yeasts compared to controls, consistent with an aberrant cellular stress response. In addition, we infected RAW 264.7 macrophages with DDR48-expressing and ddr48∆ yeasts and observed a 50% decrease in recovery of ddr48∆ yeasts compared to wild-type yeasts. Loss of DDR48 function results in numerous negative effects in Histoplasma yeasts, highlighting its role as a key player in the global sensing and response to cellular stress by fungi.
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Affiliation(s)
- Logan T. Blancett
- Center for Molecular and Cellular Biology, The University of Southern Mississippi, Hattiesburg, MS 39406, USA; (K.A.R.); (G.M.R.); (L.A.K.); (S.C.J.); (S.E.S.); (M.B.H.); (J.C.W.); (G.S.J.)
- Division of Infectious Diseases, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Kauri A. Runge
- Center for Molecular and Cellular Biology, The University of Southern Mississippi, Hattiesburg, MS 39406, USA; (K.A.R.); (G.M.R.); (L.A.K.); (S.C.J.); (S.E.S.); (M.B.H.); (J.C.W.); (G.S.J.)
- ThruPore Technologies, Inc., New Castle, DE 19720, USA
| | - Gabriella M. Reyes
- Center for Molecular and Cellular Biology, The University of Southern Mississippi, Hattiesburg, MS 39406, USA; (K.A.R.); (G.M.R.); (L.A.K.); (S.C.J.); (S.E.S.); (M.B.H.); (J.C.W.); (G.S.J.)
| | - Lauren A. Kennedy
- Center for Molecular and Cellular Biology, The University of Southern Mississippi, Hattiesburg, MS 39406, USA; (K.A.R.); (G.M.R.); (L.A.K.); (S.C.J.); (S.E.S.); (M.B.H.); (J.C.W.); (G.S.J.)
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Sydney C. Jackson
- Center for Molecular and Cellular Biology, The University of Southern Mississippi, Hattiesburg, MS 39406, USA; (K.A.R.); (G.M.R.); (L.A.K.); (S.C.J.); (S.E.S.); (M.B.H.); (J.C.W.); (G.S.J.)
| | - Sarah E. Scheuermann
- Center for Molecular and Cellular Biology, The University of Southern Mississippi, Hattiesburg, MS 39406, USA; (K.A.R.); (G.M.R.); (L.A.K.); (S.C.J.); (S.E.S.); (M.B.H.); (J.C.W.); (G.S.J.)
- Mississippi INBRE Research Scholars Program, Mississippi INBRE, The University of Southern Mississippi, Hattiesburg, MS 39406, USA
- High Containment Research Performance Core, Tulane National Primate Research Center, Covington, LA 70433, USA
| | - Mallory B. Harmon
- Center for Molecular and Cellular Biology, The University of Southern Mississippi, Hattiesburg, MS 39406, USA; (K.A.R.); (G.M.R.); (L.A.K.); (S.C.J.); (S.E.S.); (M.B.H.); (J.C.W.); (G.S.J.)
- Mississippi INBRE Research Scholars Program, Mississippi INBRE, The University of Southern Mississippi, Hattiesburg, MS 39406, USA
| | - Jamease C. Williams
- Center for Molecular and Cellular Biology, The University of Southern Mississippi, Hattiesburg, MS 39406, USA; (K.A.R.); (G.M.R.); (L.A.K.); (S.C.J.); (S.E.S.); (M.B.H.); (J.C.W.); (G.S.J.)
- Mississippi INBRE Research Scholars Program, Mississippi INBRE, The University of Southern Mississippi, Hattiesburg, MS 39406, USA
| | - Glenmore Shearer
- Center for Molecular and Cellular Biology, The University of Southern Mississippi, Hattiesburg, MS 39406, USA; (K.A.R.); (G.M.R.); (L.A.K.); (S.C.J.); (S.E.S.); (M.B.H.); (J.C.W.); (G.S.J.)
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6
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Almeida MA, Baeza LC, Almeida-Paes R, Bailão AM, Borges CL, Guimarães AJ, Soares CMA, Zancopé-Oliveira RM. Comparative Proteomic Analysis of Histoplasma capsulatum Yeast and Mycelium Reveals Differential Metabolic Shifts and Cell Wall Remodeling Processes in the Different Morphotypes. Front Microbiol 2021; 12:640931. [PMID: 34177824 PMCID: PMC8226243 DOI: 10.3389/fmicb.2021.640931] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 05/10/2021] [Indexed: 11/13/2022] Open
Abstract
Histoplasma capsulatum is a thermally dimorphic fungus distributed worldwide, but with the highest incidence in the Americas within specific geographic areas, such as the Mississippi River Valley and regions in Latin America. This fungus is the etiologic agent of histoplasmosis, an important life-threatening systemic mycosis. Dimorphism is an important feature for fungal survival in different environments and is related to the virulence of H. capsulatum, and essential to the establishment of infection. Proteomic profiles have made important contributions to the knowledge of metabolism and pathogenicity in several biological models. However, H. capsulatum proteome studies have been underexplored. In the present study, we report the first proteomic comparison between the mycelium and the yeast cells of H. capsulatum. Liquid chromatography coupled to mass spectrometry was used to evaluate the proteomic profile of the two phases of H. capsulatum growth, mycelium, and yeast. In summary, 214 and 225 proteins were only detected/or preferentially abundant in mycelium or yeast cells, respectively. In mycelium, enzymes related to the glycolytic pathway and to the alcoholic fermentation occurred in greater abundance, suggesting a higher use of anaerobic pathways for energy production. In yeast cells, proteins related to the tricarboxylic acid cycle and response to temperature stress were in high abundance. Proteins related to oxidative stress response or involved with cell wall metabolism were identified with differential abundance in both conditions. Proteomic data validation was performed by enzymatic activity determination, Western blot assays, or immunofluorescence microscopy. These experiments corroborated, directly or indirectly, the abundance of isocitrate lyase, 2-methylcitrate synthase, catalase B, and mannosyl-oligosaccharide-1,2-alpha-mannosidase in the mycelium and heat shock protein (HSP) 30, HSP60, glucosamine-fructose-6-phosphate aminotransferase, glucosamine-6-phosphate deaminase, and N-acetylglucosamine-phosphate mutase in yeast cells. The proteomic profile-associated functional classification analyses of proteins provided new and interesting information regarding the differences in metabolism between the two distinct growth forms of H. capsulatum.
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Affiliation(s)
- Marcos Abreu Almeida
- Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Lilian Cristiane Baeza
- Centro de Ciências Médicas e Farmacêuticas, Universidade Estadual do Oeste do Paraná, Cascavel, Brazil
| | - Rodrigo Almeida-Paes
- Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | | | - Clayton Luiz Borges
- Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil
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7
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Almeida MA, Almeida-Paes R, Guimarães AJ, Valente RH, Soares CMDA, Zancopé-Oliveira RM. Immunoproteomics Reveals Pathogen's Antigens Involved in Homo sapiens- Histoplasma capsulatum Interaction and Specific Linear B-Cell Epitopes in Histoplasmosis. Front Cell Infect Microbiol 2020; 10:591121. [PMID: 33251160 PMCID: PMC7673445 DOI: 10.3389/fcimb.2020.591121] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/07/2020] [Indexed: 12/15/2022] Open
Abstract
Histoplasmosis is one of the most frequent systemic mycosis in HIV patients. In these patients, histoplasmosis has high rates of morbidity/mortality if diagnosis and treatment are delayed. Despite its relevance, there is a paucity of information concerning the interaction between Histoplasma capsulatum and the human host, especially regarding the B-cell response, which has a direct impact on the diagnosis. Culture-based “gold-standard” methods have limitations, making immunodiagnostic tests an attractive option for clinical decisions. Despite the continuous development of those tests, improving serological parameters is necessary to make these methods efficient tools for definitive diagnosis of histoplasmosis. This includes the determination of more specific and immunogenic antigens to improve specificity and sensitivity of assays. In this study, we performed a co-immunoprecipitation assay between a protein extract from the yeast form of H. capsulatum and pooled sera from patients with proven histoplasmosis, followed by shotgun mass spectrometry identification of antigenic targets. Sera from patients with other pulmonary infections or from healthy individuals living in endemic areas of histoplasmosis were also assayed to determine potentially cross-reactive proteins. The primary structures of H. capsulatum immunoprecipitated proteins were evaluated using the DNAStar Protean 7.0 software. In parallel, the online epitope prediction server, BCPREDS, was used to complement the B-epitope prediction analysis. Our approach detected 132 reactive proteins to antibodies present in histoplasmosis patients’ sera. Among these antigens, 127 were recognized also by antibodies in heterologous patients’ and/or normal healthy donors’ sera. Therefore, the only three antigens specifically recognized by antibodies of histoplasmosis patients were mapped as potential antigenic targets: the M antigen, previously demonstrated in the diagnosis of histoplasmosis, and the catalase P and YPS-3 proteins, characterized as virulence factors of H. capsulatum, with antigenic properties still unclear. The other two proteins were fragments of the YPS-3 and M antigen. Overlapping results obtained from the two aforementioned bioinformatic tools, 16 regions from these three proteins are proposed as putative B-cell epitopes exclusive to H. capsulatum. These data reveal a new role for these proteins on H. capsulatum interactions with the immune system and indicate their possible use in new methods for the diagnosis of histoplasmosis.
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Affiliation(s)
- Marcos Abreu Almeida
- Laboratório de Micologia, Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Rodrigo Almeida-Paes
- Laboratório de Micologia, Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Allan Jefferson Guimarães
- Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Brazil
| | - Richard Hemmi Valente
- Laboratório de Toxinologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | | | - Rosely Maria Zancopé-Oliveira
- Laboratório de Micologia, Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
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8
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Abstract
Histoplasma capsulatum is a member of a group of fungal pathogens called thermally dimorphic fungi, all of which respond to mammalian body temperature by converting from an environmental mold form into a parasitic host form that causes disease. Histoplasma is a primary fungal pathogen, meaning it is able to cause disease in healthy individuals. We are beginning to understand how host temperature is utilized as a key signal to facilitate growth in the parasitic yeast form and promote production of virulence factors. In recent years, multiple regulators of morphology and virulence have been identified in Histoplasma. Mutations in these regulators render the pathogen unable to convert to the parasitic yeast form. Additionally, several virulence factors have been characterized for their importance in in vivo survival and pathogenesis. These virulence factors and regulators can serve as molecular handles for the development of effective drugs and therapeutics to counter Histoplasma infection.
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Affiliation(s)
- Sinem Beyhan
- Department of Infectious Diseases, J. Craig Venter Institute , La Jolla , CA , USA
| | - Anita Sil
- Department of Microbiology and Immunology, University of California , San Francisco , CA , USA
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9
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Rubio-Carrasquilla M, Santa CD, Rendón JP, Botero-Garcés J, Guimarães AJ, Moreno E, Cano LE. An interferon gamma release assay specific for Histoplasma capsulatum to detect asymptomatic infected individuals: A proof of concept study. Med Mycol 2020; 57:724-732. [PMID: 30534945 DOI: 10.1093/mmy/myy131] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 10/14/2018] [Accepted: 11/07/2018] [Indexed: 12/17/2022] Open
Abstract
Histoplasmosis is the most common endemic mycosis in the Americas. Currently, there is no laboratory test capable to detect subclinical or latent infections by Histoplasma capsulatum (Hc), which might develop as severe infections in immunocompromised individuals. For the first time to our knowledge, we explore the suitability of an interferon gamma release assay (IGRA) to detect latent Hc infection in asymptomatic individuals. A cohort of 126 volunteers was enrolled in the study, 13 of which underwent a Hc infection in the past, and 93 of them showing risk factors for this infection. The remaining 20 participants did not refer any risk factors of Hc infection, but eight of them showed evidences of infection with Mycobacterium tuberculosis. All participants were recruited in Medellin, Colombia, between January 2014 and December 2017. Whole blood samples were cultured with four different Hc crude antigens and phytohemaglutinin as positive control. The interferon (IFN)-γ released by T lymphocytes upon antigen stimulation was quantified by ELISA. A defined cutoff value of 20 pg/ml for the IFN-γ concentration allowed us to distinguish between the group with documented past infections and the group of noninfected individuals with high sensitivity (70-92%) and specificity (85-95%), for the four tested antigens. Positive 82-95% and negative 77-92% predictive values were also very high, comparable to those reported for commercially available IGRAs. The new test constitutes a promising screening method to detect individuals with latent Hc infection, even decades after the primary infection, as evidenced in this study.
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Affiliation(s)
- Marcela Rubio-Carrasquilla
- Grupo de Micología Médica y Experimental, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia.,Instituto de Biología, Universidad de Antioquia, Medellín, Colombia
| | | | - Juan Pablo Rendón
- Grupo de Micología Médica y Experimental, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia
| | | | - Allan J Guimarães
- Depto de Microbiologia e Parasitologia, Universidade Federal Fluminense, Niterói-RJ, Brasil
| | - Ernesto Moreno
- Facultad de Ciencias Básicas, Universidad de Medellín, Medellín, Colombia
| | - Luz Elena Cano
- Grupo de Micología Médica y Experimental, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia.,Escuela de Microbiología, Universidad de Antioquia, Medellín, Colombia
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10
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Mittal J, Ponce MG, Gendlina I, Nosanchuk JD. Histoplasma Capsulatum: Mechanisms for Pathogenesis. Curr Top Microbiol Immunol 2019; 422:157-191. [PMID: 30043340 PMCID: PMC7212190 DOI: 10.1007/82_2018_114] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Histoplasmosis, caused by the dimorphic environmental fungus Histoplasma capsulatum, is a major mycosis on the global stage. Acquisition of the fungus by mammalian hosts can be clinically silent or it can lead to life-threatening systemic disease, which can occur in immunologically intact or deficient hosts, albeit severe disease is more likely in the setting of compromised cellular immunity. H. capsulatum yeast cells are highly adapted to the mammalian host as they can effectively survive within intracellular niches in select phagocytic cells. Understanding the biological response by both the host and H. capsulatum will facilitate improved approaches to prevent and/or modify disease. This review presents our current understanding of the major pathogenic mechanisms involved in histoplasmosis.
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Affiliation(s)
- Jamie Mittal
- Department of Medicine (Infectious Diseases), Montefiore Medical Center, Bronx, NY, USA
| | - Maria G Ponce
- Department of Medicine (Infectious Diseases), Montefiore Medical Center, Bronx, NY, USA
| | - Inessa Gendlina
- Department of Medicine (Infectious Diseases), Albert Einstein College of Medicine, Bronx, NY, USA
| | - Joshua D Nosanchuk
- Department of Medicine (Infectious Diseases), Albert Einstein College of Medicine, Bronx, NY, USA.
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA.
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Tamayo D, Muñoz JF, Almeida AJ, Puerta JD, Restrepo Á, Cuomo CA, McEwen JG, Hernández O. Paracoccidioides spp. catalases and their role in antioxidant defense against host defense responses. Fungal Genet Biol 2017; 100:22-32. [PMID: 28093309 DOI: 10.1016/j.fgb.2017.01.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Revised: 12/20/2016] [Accepted: 01/12/2017] [Indexed: 11/30/2022]
Abstract
Dimorphic human pathogenic fungi interact with host effector cells resisting their microbicidal mechanisms. Yeast cells are able of surviving within the tough environment of the phagolysosome by expressing an antioxidant defense system that provides protection against host-derived reactive oxygen species (ROS). This includes the production of catalases (CATs). Here we identified and analyzed the role of CAT isoforms in Paracoccidioides, the etiological agent of paracoccidioidomycosis. Firstly, we found that one of these isoforms was absent in the closely related dimorphic pathogen Coccidioides and dermatophytes, but all of them were conserved in Paracoccidioides, Histoplasma and Blastomyces species. We probed the contribution of CATs in Paracoccidioides by determining the gene expression levels of each isoform through quantitative RT-qPCR, in both the yeast and mycelia phases, and during the morphological switch (transition and germination), as well as in response to oxidative agents and during interaction with neutrophils. PbCATP was preferentially expressed in the pathogenic yeast phase, and was associated to the response against exogenous H2O2. Therefore, we created and analyzed the virulence defects of a knockdown strain for this isoform, and found that CATP protects yeast cells from H2O2 generated in vitro and is relevant during lung infection. On the other hand, CATA and CATB seem to contribute to ROS homeostasis in Paracoccidioides cells, during endogenous oxidative stress. CAT isoforms in Paracoccidioides might be coordinately regulated during development and dimorphism, and differentially expressed in response to different stresses to control ROS homeostasis during the infectious process, contributing to the virulence of Paracoccidioides.
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Affiliation(s)
- Diana Tamayo
- Cellular and Molecular Biology Unit, Corporación para Investigaciones Biológicas, Medellín, Colombia; Institute of Biology, Universidad de Antioquia, Medellín, Colombia; School of Microbiology, Universidad de Antioquia, Medellín, Colombia
| | - José F Muñoz
- Cellular and Molecular Biology Unit, Corporación para Investigaciones Biológicas, Medellín, Colombia; Institute of Biology, Universidad de Antioquia, Medellín, Colombia; Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Agostinho J Almeida
- Cellular and Molecular Biology Unit, Corporación para Investigaciones Biológicas, Medellín, Colombia; Department of Biological Sciences, School of Sciences, Universidad EAFIT, Medellín, Colombia; Instituto Universitario da Maia, Maia, Portugal
| | - Juan D Puerta
- Cellular and Molecular Biology Unit, Corporación para Investigaciones Biológicas, Medellín, Colombia
| | - Ángela Restrepo
- Cellular and Molecular Biology Unit, Corporación para Investigaciones Biológicas, Medellín, Colombia
| | | | - Juan G McEwen
- Cellular and Molecular Biology Unit, Corporación para Investigaciones Biológicas, Medellín, Colombia; School of Medicine, Universidad de Antioquia, Medellín, Colombia
| | - Orville Hernández
- Cellular and Molecular Biology Unit, Corporación para Investigaciones Biológicas, Medellín, Colombia; School of Microbiology, Universidad de Antioquia, Medellín, Colombia; MICROBA Research Group, School of Microbiology, Universidad de Antioquia, Medellín, Colombia.
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12
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Huang H, Sun L, Bi K, Zhong G, Hu M. The Effect of Phenazine-1-Carboxylic Acid on the Morphological, Physiological, and Molecular Characteristics of Phellinus noxius. Molecules 2016; 21:E613. [PMID: 27187325 PMCID: PMC6273927 DOI: 10.3390/molecules21050613] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 05/04/2016] [Accepted: 05/05/2016] [Indexed: 12/04/2022] Open
Abstract
In this study, the effect of phenazine-1-carboxylic acid (PCA) on morphological, physiological, and molecular characteristics of Phellinus noxius has been investigated, and the potential antifungal mechanism of PCA against P. noxius was also explored. The results revealed that PCA showed in vitro antifungal potential against P. noxius and completely inhibited P. noxius hyphae at concentrations >40 μg/mL. PCA inhibited both mycelial growth and the loss of mycelial biomass in vitro in a dose-dependent manner. Morphological changes in PCA-treated P. noxius hyphae, such as irregularly swollen mycelia as well as short hyphae with increased septation and less branching, were observed by optical microscopy. The intracellular reactive oxygen species (ROS) levels were significantly increased in PCA-treated P. noxius cells as compared to control groups. Induced hyperpolarization of the mitochondrial membrane potential (MMP), repressed superoxide dismutase (SOD) activity and up-regulated gene expression of seven tested genes were also found in PCA-treated P. noxius groups. Thus, the present results suggested that the mechanism of action of PCA against P. noxius might be attributed to direct damage of mycelium and high intracellular ROS production, and indirect induction of genes involved in cell detoxification, oxidation-reduction process, and electron transport of the respiratory chain.
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Affiliation(s)
- Huazhi Huang
- Key Laboratory of Natural Pesticide and Chemical Biology, College of Agriculture, South China Agricultural University, Guangzhou 510642, China.
- Guangzhou Insitute of Forestry and Landscape Architecture, Guangzhou 510405, China.
| | - Longhua Sun
- Guangzhou Insitute of Forestry and Landscape Architecture, Guangzhou 510405, China.
| | - Keke Bi
- Guangzhou Insitute of Forestry and Landscape Architecture, Guangzhou 510405, China.
| | - Guohua Zhong
- Key Laboratory of Natural Pesticide and Chemical Biology, College of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Meiying Hu
- Key Laboratory of Natural Pesticide and Chemical Biology, College of Agriculture, South China Agricultural University, Guangzhou 510642, China.
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13
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Revisiting old friends: Developments in understanding Histoplasma capsulatum pathogenesis. J Microbiol 2016; 54:265-76. [DOI: 10.1007/s12275-016-6044-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 02/02/2016] [Indexed: 12/27/2022]
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14
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Toyotome T, Watanabe A, Ochiai E, Kamei K. N-acetylated α-linked acidic dipeptidase is identified as an antigen of Histoplasma capsulatum. Biochem Biophys Res Commun 2015; 458:483-487. [PMID: 25680469 DOI: 10.1016/j.bbrc.2015.01.129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 01/26/2015] [Indexed: 10/24/2022]
Abstract
Histoplasmosis, one of the most important mycoses, needs to be diagnosed rapidly and accurately. The main method used to diagnose histoplasmosis is serological detection of antibodies to the Histoplasma capsulatum H and M antigens. Several other protein antigens have been reported in H. capsulatum; however, they have not been used for diagnosis. In this study, we explored novel antigens that were detected during H. capsulatum infection. We obtained a protein mixture from H. capsulatum yeast cells after vigorous mixing in a 0.1% Triton X-100 solution. From the resultant pool, we detected nine spots that reacted with sera from patients with histoplasmosis and identified eight seroactive proteins with mass spectrometry. The seroactive proteins were purified, and their antigenicities were tested with an enzyme-linked immunosorbent assay (ELISA). ELISA revealed that the titer of the patients' sera to N-acetylated α-linked acidic dipeptidase was significantly higher than those of healthy volunteers (P < 0.01). These data indicate that N-acetylated α-linked acidic dipeptidase of H. capsulatum is recognized as a major antigen during histoplasmosis.
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Affiliation(s)
- Takahito Toyotome
- Research Unit for Risk Analysis, Diagnostic Center for Animal Health and Food Safety, Obihiro University of Agriculture and Veterinary Medicine, Nishi 2-11, Inadacho, Obihiro, Hokkaido 080-8555, Japan; Division of Clinical Research, Medical Mycology Research Center, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba 260-8673, Japan.
| | - Akira Watanabe
- Division of Clinical Research, Medical Mycology Research Center, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba 260-8673, Japan; Division of Control and Treatment of Infectious Diseases, Chiba University Hospital, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba 260-8673, Japan
| | - Eri Ochiai
- Division of Clinical Research, Medical Mycology Research Center, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba 260-8673, Japan
| | - Katsuhiko Kamei
- Division of Clinical Research, Medical Mycology Research Center, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba 260-8673, Japan; Division of Control and Treatment of Infectious Diseases, Chiba University Hospital, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba 260-8673, Japan
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15
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Purification and characterization of a mycelial catalase from Scedosporium boydii, a useful tool for specific antibody detection in patients with cystic fibrosis. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2014; 22:37-45. [PMID: 25355796 DOI: 10.1128/cvi.00482-14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Scedosporium boydii is an opportunistic filamentous fungus which may be responsible for a wide variety of infections in immunocompetent and immunocompromised individuals. This fungus belongs to the Scedosporium apiospermum species complex, which usually ranks second among the filamentous fungi colonizing the airways of patients with cystic fibrosis (CF) and may lead to allergic bronchopulmonary mycoses, sensitization, or respiratory infections. Upon microbial infection, host phagocytic cells release reactive oxygen species (ROS), such as hydrogen peroxide, as part of the antimicrobial response. Catalases are known to protect pathogens against ROS by detoxification of the hydrogen peroxide. Here, we investigated the catalase equipment of Scedosporium boydii, one of the major pathogenic species in the S. apiospermum species complex. Three catalases were identified, and the mycelial catalase A1 was purified to homogeneity by a three-step chromatographic process. This enzyme is a monofunctional tetrameric protein of 460 kDa, consisting of four 82-kDa glycosylated subunits. The potential usefulness of this enzyme in serodiagnosis of S. apiospermum infections was then investigated by an enzyme-linked immunosorbent assay (ELISA), using 64 serum samples from CF patients. Whatever the species involved in the S. apiospermum complex, sera from infected patients were clearly differentiated from sera from patients with an Aspergillus fumigatus infection or those from CF patients without clinical and biological signs of a fungal infection and without any fungus recovered from sputum samples. These results suggest that catalase A1 is a good candidate for the development of an immunoassay for serodiagnosis of infections caused by the S. apiospermum complex in patients with CF.
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16
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Baidya S, Duran RM, Lohmar JM, Harris-Coward PY, Cary JW, Hong SY, Roze LV, Linz JE, Calvo AM. VeA is associated with the response to oxidative stress in the aflatoxin producer Aspergillus flavus. EUKARYOTIC CELL 2014; 13:1095-103. [PMID: 24951443 PMCID: PMC4135802 DOI: 10.1128/ec.00099-14] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 06/14/2014] [Indexed: 12/20/2022]
Abstract
Survival of fungal species depends on the ability of these organisms to respond to environmental stresses. Osmotic stress or high levels of reactive oxygen species (ROS) can cause stress in fungi resulting in growth inhibition. Both eukaryotic and prokaryotic cells have developed numerous mechanisms to counteract and survive the stress in the presence of ROS. In many fungi, the HOG signaling pathway is crucial for the oxidative stress response as well as for osmotic stress response. This study revealed that while the osmotic stress response is only slightly affected by the master regulator veA, this gene, also known to control morphological development and secondary metabolism in numerous fungal species, has a profound effect on the oxidative stress response in the aflatoxin-producing fungus Aspergillus flavus. We found that the expression of A. flavus homolog genes involved in the HOG signaling pathway is regulated by veA. Deletion of veA resulted in a reduction in transcription levels of oxidative stress response genes after exposure to hydrogen peroxide. Furthermore, analyses of the effect of VeA on the promoters of cat1 and trxB indicate that the presence of VeA alters DNA-protein complex formation. This is particularly notable in the cat1 promoter, where the absence of VeA results in abnormally stronger complex formation with reduced cat1 expression and more sensitivity to ROS in a veA deletion mutant, suggesting that VeA might prevent binding of negative transcription regulators to the cat1 promoter. Our study also revealed that veA positively influences the expression of the transcription factor gene atfB and that normal formation of DNA-protein complexes in the cat1 promoter is dependent on AtfB.
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Affiliation(s)
- Sachin Baidya
- Department of Biological Sciences, Northern Illinois University, Dekalb, Illinois, USA
| | - Rocio M Duran
- Department of Biological Sciences, Northern Illinois University, Dekalb, Illinois, USA
| | - Jessica M Lohmar
- Department of Biological Sciences, Northern Illinois University, Dekalb, Illinois, USA
| | - Pamela Y Harris-Coward
- Southern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, New Orleans, Louisiana, USA
| | - Jeffrey W Cary
- Southern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, New Orleans, Louisiana, USA
| | - Sung-Yong Hong
- Department of Food Science and Human Nutrition, Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Ludmila V Roze
- Department of Food Science and Human Nutrition, Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - John E Linz
- Department of Food Science and Human Nutrition, Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Ana M Calvo
- Department of Biological Sciences, Northern Illinois University, Dekalb, Illinois, USA
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17
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Zhang M, Pereira e Silva MDC, Chaib De Mares M, van Elsas JD. The mycosphere constitutes an arena for horizontal gene transfer with strong evolutionary implications for bacterial-fungal interactions. FEMS Microbiol Ecol 2014; 89:516-26. [DOI: 10.1111/1574-6941.12350] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 04/24/2014] [Accepted: 04/25/2014] [Indexed: 11/29/2022] Open
Affiliation(s)
- MiaoZhi Zhang
- Department of Microbial Ecology; Centre for Life Sciences; University of Groningen; Groningen The Netherlands
| | | | - Maryam Chaib De Mares
- Department of Microbial Ecology; Centre for Life Sciences; University of Groningen; Groningen The Netherlands
| | - Jan Dirk van Elsas
- Department of Microbial Ecology; Centre for Life Sciences; University of Groningen; Groningen The Netherlands
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18
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Abstract
Gene transfer has been identified as a prevalent and pervasive phenomenon and an important source of genomic innovation in bacteria. The role of gene transfer in microbial eukaryotes seems to be of a reduced magnitude but in some cases can drive important evolutionary innovations, such as new functions that underpin the colonization of different niches. The aim of this review is to summarize published cases that support the hypothesis that horizontal gene transfer (HGT) has played a role in the evolution of phytopathogenic traits in fungi and oomycetes. Our survey of the literature identifies 46 proposed cases of transfer of genes that have a putative or experimentally demonstrable phytopathogenic function. When considering the life-cycle steps through which a pathogen must progress, the majority of the HGTs identified are associated with invading, degrading, and manipulating the host. Taken together, these data suggest HGT has played a role in shaping how fungi and oomycetes colonize plant hosts.
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Affiliation(s)
- Darren Soanes
- Biosciences, University of Exeter, Exeter, EX4 4QD, United Kingdom;
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19
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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: 46] [Impact Index Per Article: 4.2] [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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20
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Comparative transcriptomics of infectious spores from the fungal pathogen Histoplasma capsulatum reveals a core set of transcripts that specify infectious and pathogenic states. EUKARYOTIC CELL 2013; 12:828-52. [PMID: 23563482 DOI: 10.1128/ec.00069-13] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Histoplasma capsulatum is a fungal pathogen that infects both healthy and immunocompromised hosts. In regions where it is endemic, H. capsulatum grows in the soil and causes respiratory and systemic disease when inhaled by humans. An interesting aspect of H. capsulatum biology is that it adopts specialized developmental programs in response to its environment. In the soil, it grows as filamentous chains of cells (mycelia) that produce asexual spores (conidia). When the soil is disrupted, conidia aerosolize and are inhaled by mammalian hosts. Inside a host, conidia germinate into yeast-form cells that colonize immune cells and cause disease. Despite the ability of conidia to initiate infection and disease, they have not been explored on a molecular level. We developed methods to purify H. capsulatum conidia, and we show here that these cells germinate into filaments at room temperature and into yeast-form cells at 37°C. Conidia internalized by macrophages germinate into the yeast form and proliferate within macrophages, ultimately lysing the host cells. Similarly, infection of mice with purified conidia is sufficient to establish infection and yield viable yeast-form cells in vivo. To characterize conidia on a molecular level, we performed whole-genome expression profiling of conidia, yeast, and mycelia from two highly divergent H. capsulatum strains. In parallel, we used homology and protein domain analysis to manually annotate the predicted genes of both strains. Analyses of the resultant data defined sets of transcripts that reflect the unique molecular states of H. capsulatum conidia, yeast, and mycelia.
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21
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Hansberg W, Salas-Lizana R, Domínguez L. Fungal catalases: Function, phylogenetic origin and structure. Arch Biochem Biophys 2012; 525:170-80. [DOI: 10.1016/j.abb.2012.05.014] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2012] [Revised: 05/18/2012] [Accepted: 05/21/2012] [Indexed: 11/16/2022]
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Extracellular superoxide dismutase protects Histoplasma yeast cells from host-derived oxidative stress. PLoS Pathog 2012; 8:e1002713. [PMID: 22615571 PMCID: PMC3355102 DOI: 10.1371/journal.ppat.1002713] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 04/04/2012] [Indexed: 12/05/2022] Open
Abstract
In order to establish infections within the mammalian host, pathogens must protect themselves against toxic reactive oxygen species produced by phagocytes of the immune system. The fungal pathogen Histoplasma capsulatum infects both neutrophils and macrophages but the mechanisms enabling Histoplasma yeasts to survive in these phagocytes have not been fully elucidated. We show that Histoplasma yeasts produce a superoxide dismutase (Sod3) and direct it to the extracellular environment via N-terminal and C-terminal signals which promote its secretion and association with the yeast cell surface. This localization permits Sod3 to protect yeasts specifically from exogenous superoxide whereas amelioration of endogenous reactive oxygen depends on intracellular dismutases such as Sod1. While infection of resting macrophages by Histoplasma does not stimulate the phagocyte oxidative burst, interaction with polymorphonuclear leukocytes (PMNs) and cytokine-activated macrophages triggers production of reactive oxygen species (ROS). Histoplasma yeasts producing Sod3 survive co-incubation with these phagocytes but yeasts lacking Sod3 are rapidly eliminated through oxidative killing similar to the effect of phagocytes on Candida albicans yeasts. The protection provided by Sod3 against host-derived ROS extends in vivo. Without Sod3, Histoplasma yeasts are attenuated in their ability to establish respiratory infections and are rapidly cleared with the onset of adaptive immunity. The virulence of Sod3-deficient yeasts is restored in murine hosts unable to produce superoxide due to loss of the NADPH-oxidase function. These results demonstrate that phagocyte-produced ROS contributes to the immune response to Histoplasma and that Sod3 facilitates Histoplasma pathogenesis by detoxifying host-derived reactive oxygen thereby enabling Histoplasma survival. Histoplasma capsulatum is a fungal pathogen that is endemic to the Mississippi and Ohio River valleys. An estimated 200,000 infections occur annually in the United States. Histoplasma is adept at surviving within both neutrophils and macrophages, which normally kill fungal cells by producing reactive oxygen molecules that are toxic to microbes. In this study, we demonstrate the role of a superoxide dismutase enzyme (Sod3) produced by Histoplasma cells and we show that it enables Histoplasma to survive these reactive oxidative molecules produced by the host. We show that Histoplasma directs the Sod3 protein to the surface of yeast cells and into the extracellular environment, positioning it to destroy extracellular superoxide produced by neutrophils and macrophages. Our results highlight the importance of reactive oxygen produced by immune cells and define the mechanism by which Histoplasma survives these immune defenses and establishes infections in its host.
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23
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SRE1 regulates iron-dependent and -independent pathways in the fungal pathogen Histoplasma capsulatum. EUKARYOTIC CELL 2011; 11:16-25. [PMID: 22117028 DOI: 10.1128/ec.05274-11] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Regulation of iron acquisition genes is critical for microbial survival under both iron-limiting conditions (to acquire essential iron) and iron-replete conditions (to limit iron toxicity). In fungi, iron acquisition genes are repressed under iron-replete conditions by a conserved GATA transcriptional regulator. Here we investigate the role of this transcription factor, Sre1, in the cellular responses of the fungal pathogen Histoplasma capsulatum to iron. We showed that cells in which SRE1 levels were diminished by RNA interference were unable to repress siderophore biosynthesis and utilization genes in the presence of abundant iron and thus produced siderophores even under iron-replete conditions. Mutation of a GATA-containing consensus site found in the promoters of these genes also resulted in inappropriate gene expression under iron-replete conditions. Microarray analysis comparing control and SRE1-depleted strains under conditions of iron limitation or abundance revealed both iron-responsive genes and Sre1-dependent genes, which comprised distinct but overlapping sets. Iron-responsive genes included those encoding putative oxidoreductases, metabolic and mitochondrial enzymes, superoxide dismutase, and nitrosative-stress-response genes; Sre1-dependent genes were of diverse functions. Genes regulated by iron levels and Sre1 included all of the siderophore biosynthesis genes, a gene involved in reductive iron acquisition, an iron-responsive transcription factor, and two catalases. Based on transcriptional profiling and phenotypic analyses, we conclude that Sre1 plays a critical role in the regulation of both traditional iron-responsive genes and iron-independent pathways such as regulation of cell morphology. These data highlight the evolving realization that the effect of Sre1 orthologs on fungal biology extends beyond the iron regulon.
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24
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Guimarães AJ, de Cerqueira MD, Nosanchuk JD. Surface architecture of histoplasma capsulatum. Front Microbiol 2011; 2:225. [PMID: 22121356 PMCID: PMC3220077 DOI: 10.3389/fmicb.2011.00225] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Accepted: 10/25/2011] [Indexed: 12/22/2022] Open
Abstract
The dimorphic fungal pathogen Histoplasma capsulatum is the most frequent cause of clinically significant fungal pneumonia in humans. H. capsulatum virulence is achieved, in part, through diverse and dynamic alterations to the fungal cell surface. Surface components associated with H. capsulatum pathogenicity include carbohydrates, lipids, proteins, and melanins. Here, we describe the various structures comprising the cell surface of H. capsulatum that have been associated with virulence and discuss their involvement in the pathobiology of disease.
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Affiliation(s)
- Allan J Guimarães
- Department of Microbiology and Imunology, Albert Einstein College of Medicine of Yeshiva University Bronx, NY, USA
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25
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Edwards JA, Rappleye CA. Histoplasma mechanisms of pathogenesis--one portfolio doesn't fit all. FEMS Microbiol Lett 2011; 324:1-9. [PMID: 22092757 PMCID: PMC3228276 DOI: 10.1111/j.1574-6968.2011.02363.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Revised: 07/12/2011] [Accepted: 07/13/2011] [Indexed: 01/15/2023] Open
Abstract
Histoplasma capsulatum is the leading cause of endemic mycosis in the world. Analyses of clinical isolates from different endemic regions show important diversity within the species. Recent molecular studies of two isolates, the Chemotype I NAm2 strain G217B and the Chemotype II Panamanian strain G186A, reveal significant genetic, structural, and molecular differences between these representative Histoplasma strains. Some of these variations have functional consequences, representing distinct molecular mechanisms that facilitate Histoplasma pathogenesis. The realization of Histoplasma strain diversity highlights the importance of characterizing Histoplasma virulence factors in the context of specific clinical strain isolates.
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Affiliation(s)
- Jessica A. Edwards
- Departments of Microbiology and Internal Medicine, The Center for Microbial Interface Biology, Ohio State University, 484 W. 12Avenue, Columbus, OH 43210, USA
| | - Chad A. Rappleye
- Departments of Microbiology and Internal Medicine, The Center for Microbial Interface Biology, Ohio State University, 484 W. 12Avenue, Columbus, OH 43210, USA
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26
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Holbrook ED, Edwards JA, Youseff BH, Rappleye CA. Definition of the extracellular proteome of pathogenic-phase Histoplasma capsulatum. J Proteome Res 2011; 10:1929-43. [PMID: 21291285 PMCID: PMC3069693 DOI: 10.1021/pr1011697] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Indexed: 11/30/2022]
Abstract
The dimorphic fungal pathogen Histoplasma capsulatum causes respiratory and systemic disease. Within the mammalian host, pathogenic Histoplasma yeast infect, replicate within, and ultimately kill host phagocytes. Surprisingly, few factors have been identified that contribute to Histoplasma virulence. To address this deficiency, we have defined the constituents of the extracellular proteome using LC-MS/MS analysis of the proteins in pathogenic-phase culture filtrates of Histoplasma. In addition to secreted Cbp1, the extracellular proteome of pathogenic Histoplasma yeast consists of 33 deduced proteins. The proteins include glycanases, extracellular enzymes related to oxidative stress defense, dehydrogenase enzymes, chaperone-like factors, and five novel culture filtrate proteins (Cfp's). For independent verification of proteomics-derived identities, we employed RNA interference (RNAi)-based depletion of candidate factors and showed loss of specific proteins from the cell-free culture filtrate. Quantitative RT-PCR revealed the expression of 10 of the extracellular factors was particularly enriched in pathogenic yeast cells as compared to nonpathogenic Histoplasma mycelia, suggesting that these proteins are linked to Histoplasma pathogenesis. In addition, Histoplasma yeast express these factors within macrophages and during infection of murine lungs. As extracellular proteins are positioned at the interface between host and pathogen, the definition of the pathogenic-phase extracellular proteome provides a foundation for the molecular dissection of how Histoplasma alters the host-pathogen interaction to its advantage.
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Affiliation(s)
- Eric D. Holbrook
- Departments of Microbiology and Internal Medicine, The Center for Microbial Interface Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Jessica A. Edwards
- Departments of Microbiology and Internal Medicine, The Center for Microbial Interface Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Brian H. Youseff
- Departments of Microbiology and Internal Medicine, The Center for Microbial Interface Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Chad A. Rappleye
- Departments of Microbiology and Internal Medicine, The Center for Microbial Interface Biology, The Ohio State University, Columbus, Ohio 43210, United States
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Roetzer A, Gratz N, Kovarik P, Schüller C. Autophagy supports Candida glabrata survival during phagocytosis. Cell Microbiol 2009; 12:199-216. [PMID: 19811500 PMCID: PMC2816358 DOI: 10.1111/j.1462-5822.2009.01391.x] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The opportunistic human fungal pathogen Candida glabrata is confronted with phagocytic cells of the host defence system. Survival of internalized cells is thought to contribute to successful dissemination. We investigated the reaction of engulfed C. glabrata cells using fluorescent protein fusions of the transcription factors CgYap1 and CgMig1 and catalase CgCta1. The expression level and peroxisomal localization of catalase was used to monitor the metabolic and stress status of internalized C. glabrata cells. These reporters revealed that the phagocytosed C. glabrata cells were exposed to transient oxidative stress and starved for carbon source. Cells trapped within macrophages increased their peroxisome numbers indicating a metabolic switch. Prolonged phagocytosis caused a pexophagy-mediated decline in peroxisome numbers. Autophagy, and in particular pexophagy, contributed to survival of C. glabrata during engulfment. Mutants lacking CgATG11 or CgATG17, genes required for pexophagy and non-selective autophagy, respectively, displayed reduced survival rates. Furthermore, both CgAtg11 and CgAtg17 contribute to survival, since the double mutant was highly sensitive to engulfment. Inhibition of peroxisome formation by deletion of CgPEX3 partially restored viability of CgATG11 deletion mutants during engulfment. This suggests that peroxisome formation and maintenance might sequester resources required for optimal survival. Mobilization of intracellular resources via autophagy is an important virulence factor that supports the viability of C. glabrata in the phagosomal compartment of infected innate immune cells.
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Affiliation(s)
- Andreas Roetzer
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
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28
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Nakagawa Y. [Oxidative stress responses in pathogenic fungi]. Nihon Saikingaku Zasshi 2009; 63:417-24. [PMID: 19317231 DOI: 10.3412/jsb.63.417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Yoshiyuki Nakagawa
- Division of Molecular Mycology and Medicine, Center for Neurological Disease and Cancer, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Syowa-ku, Nagoya 466-8550
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Guimarães AJ, Hamilton AJ, de M. Guedes HL, Nosanchuk JD, Zancopé-Oliveira RM. Biological function and molecular mapping of M antigen in yeast phase of Histoplasma capsulatum. PLoS One 2008; 3:e3449. [PMID: 18927619 PMCID: PMC2566600 DOI: 10.1371/journal.pone.0003449] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 09/24/2008] [Indexed: 11/23/2022] Open
Abstract
Histoplasmosis, due to the intracellular fungus Histoplasma capsulatum, can be diagnosed by demonstrating the presence of antibodies specific to the immunodominant M antigen. However, the role of this protein in the pathogenesis of histoplasmosis has not been elucidated. We sought to structurally and immunologically characterize the protein, determine yeast cell surface expression, and confirm catalase activity. A 3D-rendering of the M antigen by homology modeling revealed that the structures and domains closely resemble characterized fungal catalases. We generated monoclonal antibodies (mAbs) to the protein and determined that the M antigen is present on the yeast cell surface and in cell wall/cell membrane preparations. Similarly, we found that the majority of catalase activity was in extracts containing fungal surface antigens and that the M antigen is not significantly secreted by live yeast cells. The mAbs also identified unique epitopes on the M antigen. The localization of the M antigen to the cell surface of H. capsulatum yeast and the characterization of the protein's major epitopes have important implications since it demonstrates that although the protein may participate in protecting the fungus against oxidative stress it is also accessible to host immune cells and antibody.
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Affiliation(s)
- Allan Jefferson Guimarães
- Division of Infectious Diseases, Department of Medicine and Microbiology and Immunology, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York, United States of America
- Laboratório de Micologia - Setor de Imunodiagnóstico - Instituto de Pesquisa Clínica Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Andrew John Hamilton
- St John's Institute of Dermatology, Guy's Hospital, King's College, London, United Kingdom
| | - Herbert Leonel de M. Guedes
- Laboratório de Micologia - Setor de Imunodiagnóstico - Instituto de Pesquisa Clínica Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
- Laboratório de Bioquímica de Proteínas e Peptídeos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Joshua Daniel Nosanchuk
- Division of Infectious Diseases, Department of Medicine and Microbiology and Immunology, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York, United States of America
- * E-mail:
| | - Rosely Maria Zancopé-Oliveira
- Laboratório de Micologia - Setor de Imunodiagnóstico - Instituto de Pesquisa Clínica Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
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30
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Differential mRNA expression of Sporothrix schenckii catalase gene in two growth phases and effect factors. Chin Med J (Engl) 2008. [DOI: 10.1097/00029330-200810020-00029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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31
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Chagas RF, Bailão AM, Pereira M, Winters MS, Smullian AG, Deepe GS, de Almeida Soares CM. The catalases of Paracoccidioides brasiliensis are differentially regulated: protein activity and transcript analysis. Fungal Genet Biol 2008; 45:1470-8. [PMID: 18799136 DOI: 10.1016/j.fgb.2008.08.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Revised: 08/21/2008] [Accepted: 08/22/2008] [Indexed: 11/29/2022]
Abstract
Paracoccidioides brasiliensis is a fungal pathogen of humans. The P. brasiliensis response to oxidative stress is largely unexplored. We report the analysis of three catalases, PbCatA, PbCatP and PbCatC. The former are monofunctional catalases and the latter is a catalase-peroxidase. Differential expression of catalases as measured by activity and by quantitative analysis of transcripts was observed in the morphological conversion and in response to different stress conditions. PbCatA manifested higher activity in the mycelial phase, showed increased activity during transition from mycelium to yeast and during conditions of endogenous oxidative stress. Consistent with our previous studies, PbCatP manifested higher activity in yeast cells since it is putatively involved in the control of exogenous reactive oxygen species. P. brasiliensis displays an oxidative stress response following phagocytosis by macrophages, inducing the expression of catalase A and P transcripts. PbCatC displayed a relatively constant pattern of expression, being modestly induced in cells exposed to osmotic and heat stress.
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Affiliation(s)
- Ronney Fernandes Chagas
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Campus II, Universidade Federal de Goiás, 74001-970 Goiânia, Goiás, Brazil
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32
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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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33
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Skamnioti P, Henderson C, Zhang Z, Robinson Z, Gurr SJ. A novel role for catalase B in the maintenance of fungal cell-wall integrity during host invasion in the rice blast fungus Magnaporthe grisea. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2007; 20:568-80. [PMID: 17506334 DOI: 10.1094/mpmi-20-5-0568] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Asexual spores of the rice blast fungus germinate to produce a specialized and melanized infection structure, the appressorium, which is pivotal to successful plant penetration. To investigate whether Magnaporthe grisea counteracts the toxic burst of H2O2 localized beneath the site of attempted invasion, we examined the temporal expression of five candidate antioxidant genes. Of these, the putatively secreted large subunit catalase CATB gene was 600-fold up-regulated in vivo, coincident with penetration, and moderately up-regulated in vitro, in response to exogenous H2O2. Targeted gene replacement of CATB led to compromised pathogen fitness; the catB mutant displayed paler pigmentation and accelerated hyphal growth but lower biomass, poorer sporulation, fragile conidia and appressoria, and impaired melanization. The catB mutant was severely less pathogenic than Guy 11 on barley and rice, and its infectivity was further reduced on exposure to H2O2. The wild-type phenotype was restored by the reintroduction of CATB into the catB mutant We found no evidence to support a role for CATB in detoxification of the host-derived H2O2 at the site of penetration. Instead, we demonstrated that CATB plays a part in strengthening the fungal wall, a role of particular importance during forceful entry into the host.
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Affiliation(s)
- Pari Skamnioti
- Department of Plant Sciences, South Parks Road, University of Oxford, OX1 3RB, UK
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34
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Bohse ML, Woods JP. RNA interference-mediated silencing of the YPS3 gene of Histoplasma capsulatum reveals virulence defects. Infect Immun 2007; 75:2811-7. [PMID: 17403872 PMCID: PMC1932869 DOI: 10.1128/iai.00304-07] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The YPS3 gene of Histoplasma capsulatum encodes a protein that is both surface localized in the cell wall of H. capsulatum and released into the culture medium. This protein is produced only during the pathogenic yeast phase of infection and is also expressed differentially in H. capsulatum strains of different virulence levels. In this study, we silenced the YPS3 transcript by using an interfering-RNA strategy and examined the silenced mutants for phenotypic differences in vitro and during infection. The mutants showed no growth defect during in vitro culture in a defined medium at 37 degrees C and appeared to have normal virulence in a RAW 264.7 murine macrophage-like cell line. In a C57BL/6 mouse model of infection, however, the mutants caused significantly decreased fungal burdens, particularly in the peripheral phagocyte-rich tissues of livers and spleens. This defect in organ colonization was evident within 3 days of infection; however, it appeared to be exacerbated at later time points.
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Affiliation(s)
- Megan L Bohse
- Department of Medical Microbiology and Immunology, 420 SMI, University of Wisconsin Medical School, 1300 University Avenue, Madison, WI 53706, USA
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35
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Bohse ML, Woods JP. Expression and interstrain variability of the YPS3 gene of Histoplasma capsulatum. EUKARYOTIC CELL 2007; 6:609-15. [PMID: 17337639 PMCID: PMC1865658 DOI: 10.1128/ec.00010-07] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The YPS3 locus of the dimorphic fungus Histoplasma capsulatum encodes a secreted and surface-localized protein specific to the pathogenic yeast phase. In this study we examined this locus in 32 H. capsulatum strains and variants. Although protein production is limited to a select group of strains, the North American restriction fragment length polymorphism class 2/NAm 2 isolates, the locus was present in all the strains we examined. The YPS3 gene is well conserved in its 5' and 3' regions but displays an intragenic hypervariable region of tandem repeats that fluctuates in size between strains. This feature is similar to that seen with genes encoding several cell surface proteins in other fungi.
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Affiliation(s)
- Megan L Bohse
- Department of Medical Microbiology and Immunology, 420 SMI, University of Wisconsin Medical School, 1300 University Avenue, Madison, WI 53706, USA
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36
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Giles SS, Stajich JE, Nichols C, Gerrald QD, Alspaugh JA, Dietrich F, Perfect JR. The Cryptococcus neoformans catalase gene family and its role in antioxidant defense. EUKARYOTIC CELL 2006; 5:1447-59. [PMID: 16963629 PMCID: PMC1563583 DOI: 10.1128/ec.00098-06] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In the present study, we sought to elucidate the contribution of the Cryptococcus neoformans catalase gene family to antioxidant defense. We employed bioinformatics techniques to identify four members of the C. neoformans catalase gene family and created mutants lacking single or multiple catalase genes. Based on a phylogenetic analysis, CAT1 and CAT3 encode putative spore-specific catalases, CAT2 encodes a putative peroxisomal catalase, and CAT4 encodes a putative cytosolic catalase. Only Cat1 exhibited detectable biochemical activity in vitro, and Cat1 activity was constitutive in the yeast form of this organism. Although they were predicted to be important in spores, neither CAT1 nor CAT3 was essential for mating or spore viability. Consistent with previous studies of Saccharomyces cerevisiae, the single (cat1, cat2, cat3, and cat4) and quadruple (cat1 cat2 cat3 cat4) catalase mutant strains exhibited no oxidative-stress phenotypes under conditions in which either exogenous or endogenous levels of reactive oxygen species were elevated. In addition, there were no significant differences in the mean times to mortality between groups of mice infected with C. neoformans catalase mutant strains (the cat1 and cat1 cat2 cat3 cat4 mutants) and those infected with wild-type strain H99. We conclude from the results of this study that C. neoformans possesses a robust antioxidant system, composed of functionally overlapping and compensatory components that provide protection against endogenous and exogenous oxidative stresses.
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Affiliation(s)
- Steven S Giles
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
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37
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Schliebs W, Würtz C, Kunau WH, Veenhuis M, Rottensteiner H. A eukaryote without catalase-containing microbodies: Neurospora crassa exhibits a unique cellular distribution of its four catalases. EUKARYOTIC CELL 2006; 5:1490-502. [PMID: 16963632 PMCID: PMC1563580 DOI: 10.1128/ec.00113-06] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Microbodies usually house catalase to decompose hydrogen peroxide generated within the organelle by the action of various oxidases. Here we have analyzed whether peroxisomes (i.e., catalase-containing microbodies) exist in Neurospora crassa. Three distinct catalase isoforms were identified by native catalase activity gels under various peroxisome-inducing conditions. Subcellular fractionation by density gradient centrifugation revealed that most of the spectrophotometrically measured activity was present in the light upper fractions, with an additional small peak coinciding with the peak fractions of HEX-1, the marker protein for Woronin bodies, a compartment related to the microbody family. However, neither in-gel assays nor monospecific antibodies generated against the three purified catalases detected the enzymes in any dense organellar fraction. Furthermore, staining of an N. crassa wild-type strain with 3,3'-diaminobenzidine and H(2)O(2) did not lead to catalase-dependent reaction products within microbodies. Nonetheless, N. crassa does possess a gene (cat-4) whose product is most similar to the peroxisomal type of monofunctional catalases. This novel protein indeed exhibited catalase activity, but was not localized to microbodies either. We conclude that N. crassa lacks catalase-containing peroxisomes, a characteristic that is probably restricted to a few filamentous fungi that produce little hydrogen peroxide within microbodies.
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Affiliation(s)
- Wolfgang Schliebs
- Institut für Physiologische Chemie, Abt. Systembiochemie, Ruhr-Universität Bochum, D-44780 Bochum, Germany
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38
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Abstract
Most dimorphic fungal pathogens cause respiratory disease in mammals and must therefore possess virulence mechanisms to combat and overcome host pulmonary defenses. Over the past decade, advances in genetic tools have made it possible to investigate the basis of dimorphic fungal pathogenesis at the molecular level. Gene disruptions and RNA interference have now formally demonstrated the involvement of six virulence factors: CBP, alpha-(1,3)-glucan, BAD1, SOWgp, Mep1, and urease. Additional candidate virulence-associated genes have been identified on the premise that factors necessary for pathogenicity are associated specifically with the parasitic form. This principle continues to form the foundation for genomics-based analyses to further augment the list. Thus, the stage is set and the tools are in place for the next phase of medical mycology research: defining the virulence-associated factors underlying the success of dimorphic fungal pathogens.
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Affiliation(s)
- Chad A Rappleye
- Department of Microbiology, Ohio State University, Columbus, Ohio 43210, USA.
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39
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Vanittanakom N, Cooper CR, Fisher MC, Sirisanthana T. Penicillium marneffei infection and recent advances in the epidemiology and molecular biology aspects. Clin Microbiol Rev 2006; 19:95-110. [PMID: 16418525 PMCID: PMC1360277 DOI: 10.1128/cmr.19.1.95-110.2006] [Citation(s) in RCA: 348] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Penicillium marneffei infection is an important emerging public health problem, especially among patients infected with human immunodeficiency virus in the areas of endemicity in southeast Asia, India, and China. Within these regions, P. marneffei infection is regarded as an AIDS-defining illness, and the severity of the disease depends on the immunological status of the infected individual. Early diagnosis by serologic and molecular assay-based methods have been developed and are proving to be important in diagnosing infection. The occurrence of natural reservoirs and the molecular epidemiology of P. marneffei have been studied; however, the natural history and mode of transmission of the organism remain unclear. Soil exposure, especially during the rainy season, has been suggested to be a critical risk factor. Using a highly discriminatory molecular technique, multilocus microsatellite typing, to characterize this fungus, several isolates from bamboo rats and humans were shown to share identical multilocus genotypes. These data suggest either that transmission of P. marneffei may occur from rodents to humans or that rodents and humans are coinfected from common environmental sources. These putative natural cycles of P. marneffei infection need further investigation. Studies on the fungal genetics of P. marneffei have been focused on the characterization of genetic determinants that may play important roles in asexual development, mycelial-to-yeast phase transition, and the expression of antigenic determinants. Molecular studies have identified several genes involved in germination, hyphal development, conidiogenesis, and yeast cell polarity. A number of functionally important genes, such as the malate synthase- and catalase-peroxidase protein-encoding genes, have been identified as being upregulated in the yeast phase. Future investigations pertaining to the roles of these genes in host-fungus interactions may provide the key knowledge to understanding the pathogenicity of P. marneffei.
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Affiliation(s)
- Nongnuch Vanittanakom
- Department of Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
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40
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Missall TA, Lodge JK, McEwen JE. Mechanisms of resistance to oxidative and nitrosative stress: implications for fungal survival in mammalian hosts. EUKARYOTIC CELL 2005; 3:835-46. [PMID: 15302816 PMCID: PMC500878 DOI: 10.1128/ec.3.4.835-846.2004] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Tricia A Missall
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, 1402 S. Grand Blvd., St. Louis, MO 63104, USA
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41
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Bohse ML, Woods JP. Surface localization of the Yps3p protein of Histoplasma capsulatum. EUKARYOTIC CELL 2005; 4:685-93. [PMID: 15821128 PMCID: PMC1087815 DOI: 10.1128/ec.4.4.685-693.2005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The YPS3 gene of Histoplasma capsulatum encodes a protein that is both resident in the cell wall and also released into the culture medium. This protein is produced only during the pathogenic yeast phase of infection and is also expressed differently in H. capsulatum strains that differ in virulence. We investigated the cellular localization of Yps3p. We demonstrated that the cell wall fraction of Yps3p was surface localized in restriction fragment length polymorphism class 2 strains. We also established that Yps3p released into the G217B culture supernatant binds to the surface of strains that do not naturally express the protein. This binding was saturable and occurred within 5 min of exposure and occurred similarly with live and heat-killed H. capsulatum. Flow cytometric analysis of H. capsulatum after enzymatic treatments was consistent with Yps3p binding to chitin, a carbohydrate polymer that is a component of fungal cell walls. Polysaccharide binding assays demonstrated that chitin but not cellulose binds to and extracts Yps3p from culture supernatants.
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Affiliation(s)
- Megan L Bohse
- Department of Medical Microbiology and Immunology, University of Wisconsin Medical School, Madison, Wisconsin 53706-1532, USA
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42
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Díaz A, Muñoz-Clares RA, Rangel P, Valdés VJ, Hansberg W. Functional and structural analysis of catalase oxidized by singlet oxygen. Biochimie 2005; 87:205-14. [PMID: 15760714 DOI: 10.1016/j.biochi.2004.10.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Accepted: 10/22/2004] [Indexed: 11/25/2022]
Abstract
Purified catalase-1 (CAT-1) from Neurospora crassa asexual spores is oxidized by singlet oxygen giving rise to active enzyme forms with different electrophoretic mobility. These enzyme forms are detected in vivo under stress conditions and during development at the start of the asexual morphogenetic transitions. CAT-1 heme b is oxidized to heme d by singlet oxygen. Here, we describe functional and structural comparisons of the non-oxidized enzyme with the fully oxidized one. Using a broad H(2)O(2) concentration range (0.01-3.0 M), non-hyperbolic saturation kinetics was found in both enzymes, indicating that kinetic complexity does not arise from heme oxidation. The kinetics was consistent with the existence of two kinds of active sites differing more than 10-times in substrate affinity. Positive cooperativity for one or both of the saturation curves is possible. Kinetic constants obtained at 22 degrees C varied slightly and apparent activation energies for the reaction of both components are not significantly different. Protein fluorescence and circular dicroism of the two enzymes were nearly identical, indicating no gross conformational change with oxidation. Increased sensitivity to inhibition by cyanide indicated a local change at the active site in the oxidized catalase. Oxidized catalase was less resistant to high temperatures, high guanidinium ion concentration, and digestion with subtilisin. It was also less stable than the non-oxidized enzyme at an acid pH. The overall data show that the oxidized enzyme is structurally different from the non-oxidized one, although it conserves most of the remarkable stability and catalytic efficiency of the non-oxidized enzyme. Because the enzyme in the cell can be oxidized under physiological conditions, preservation of functional and structural properties of catalase could have been selected through evolution to assure an active enzyme under oxidative stress conditions.
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Affiliation(s)
- Adelaida Díaz
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México D.F., Mexico
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43
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Fast NM, Law JS, Williams BAP, Keeling PJ. Bacterial catalase in the microsporidian Nosema locustae: implications for microsporidian metabolism and genome evolution. EUKARYOTIC CELL 2004; 2:1069-75. [PMID: 14555490 PMCID: PMC219363 DOI: 10.1128/ec.2.5.1069-1075.2003] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Microsporidia constitute a group of extremely specialized intracellular parasites that infect virtually all animals. They are highly derived, reduced fungi that lack several features typical of other eukaryotes, including canonical mitochondria, flagella, and peroxisomes. Consistent with the absence of peroxisomes in microsporidia, the recently completed genome of the microsporidian Encephalitozoon cuniculi lacks a gene for catalase, the major enzymatic marker for the organelle. We show, however, that the genome of the microsporidian Nosema locustae, in contrast to that of E. cuniculi, encodes a group II large-subunit catalase. Surprisingly, phylogenetic analyses indicate that the N. locustae catalase is not specifically related to fungal homologs, as one would expect, but is instead closely related to proteobacterial sequences. This finding indicates that the N. locustae catalase is derived by lateral gene transfer from a bacterium. The catalase gene is adjacent to a large region of the genome that appears to be far less compact than is typical of microsporidian genomes, a characteristic which may make this region more amenable to the insertion of foreign genes. The N. locustae catalase gene is expressed in spores, and the protein is detectable by Western blotting. This type of catalase is a particularly robust enzyme that has been shown to function in dormant cells, indicating that the N. locustae catalase may play some functional role in the spore. There is no evidence that the N. locustae catalase functions in a cryptic peroxisome.
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Affiliation(s)
- Naomi M Fast
- Canadian Institute for Advanced Research, Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4.
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44
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Michán S, Lledías F, Hansberg W. Asexual development is increased in Neurospora crassa cat-3-null mutant strains. EUKARYOTIC CELL 2003; 2:798-808. [PMID: 12912899 PMCID: PMC178387 DOI: 10.1128/ec.2.4.798-808.2003] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We use asexual development of Neurospora crassa as a model system with which to determine the causes of cell differentiation. Air exposure of a mycelial mat induces hyphal adhesion, and adherent hyphae grow aerial hyphae that, in turn, form conidia. Previous work indicated the development of a hyperoxidant state at the start of these morphogenetic transitions and a large increase in catalase activity during conidiation. Catalase 3 (CAT-3) increases at the end of exponential growth and is induced by different stress conditions. Here we analyzed the effects of cat-3-null strains on growth and asexual development. The lack of CAT-3 was not compensated by other catalases, even under oxidative stress conditions, and cat-3(RIP) colonies were sensitive to H(2)O(2), indicating that wild-type (Wt) resistance to external H(2)O(2) was due to CAT-3. cat-3(RIP) colonies grown in the dark produced high levels of carotenes as a consequence of oxidative stress. Light exacerbated oxidative stress and further increased carotene synthesis. In the cat-3(RIP) mutant strain, increased aeration in liquid cultures led to increased hyphal adhesion and protein oxidation. Compared to the Wt, the cat-3(RIP) mutant strain produced six times more aerial hyphae and conidia in air-exposed mycelial mats, as a result of longer and more densely packed aerial hyphae. Protein oxidation in colonies was threefold higher and showed more aerial hyphae and conidia in mutant strains than did the Wt. Results indicate that oxidative stress due to lack of CAT-3 induces carotene synthesis, hyphal adhesion, and more aerial hyphae and conidia.
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Affiliation(s)
- Shaday Michán
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, DF, México
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Hwang L, Hocking-Murray D, Bahrami AK, Andersson M, Rine J, Sil A. Identifying phase-specific genes in the fungal pathogen Histoplasma capsulatum using a genomic shotgun microarray. Mol Biol Cell 2003; 14:2314-26. [PMID: 12808032 PMCID: PMC194881 DOI: 10.1091/mbc.e03-01-0027] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
A fundamental feature of the fungal pathogen Histoplasma capsulatum is its ability to shift from a mycelial phase in the soil to a yeast phase in its human host. Each form plays a critical role in infection and disease, but little is understood about how these two morphologic phases are established and maintained. To identify phase-regulated genes of H. capsulatum, we carried out expression analyses by using a genomic shotgun microarray representing approximately one-third of the genome, and identified 500 clones that were differentially expressed. Genes induced in the mycelial phase included several involved in conidiation, cell polarity, and melanin production in other organisms. Genes induced in the yeast phase included several involved in sulfur metabolism, extending previous observations that sulfur metabolism influences morphology in H. capsulatum. Other genes with increased expression in the yeast phase were implicated in nutrient acquisition and cell cycle regulation. Unexpectedly, differential regulation of the site of transcript initiation was also observed in the two phases. These findings identify genes that may determine some of the major characteristics of the mycelial and yeast phases.
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Affiliation(s)
- Lena Hwang
- Department of Molecular and Cellular Biology, University of California Berkeley, 94720, USA
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Paris S, Wysong D, Debeaupuis JP, Shibuya K, Philippe B, Diamond RD, Latgé JP. Catalases of Aspergillus fumigatus. Infect Immun 2003; 71:3551-62. [PMID: 12761140 PMCID: PMC155756 DOI: 10.1128/iai.71.6.3551-3562.2003] [Citation(s) in RCA: 164] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Upon infection of a host, the pathogenic fungus Aspergillus fumigatus is attacked by the reactive oxygen species produced by phagocytic cells. Detoxification of hydrogen peroxide by catalases was proposed as a way to overcome this host response. A. fumigatus produces three active catalases; one is produced by conidia, and two are produced by mycelia. The mycelial catalase Cat1p was studied previously. Here we characterized the two other catalases, their genes, and the phenotypes of gene-disrupted mutants. CatAp, a spore-specific monofunctional catalase, is resistant to heat, metal ions, and detergent. This enzyme is a dimeric protein with 84.5-kDa subunits. The 749-amino-acid polypeptide exhibits high levels of similarity to the Aspergillus nidulans CatA catalase and to bacterial catalase HPII of Escherichia coli. In spite of increased sensitivity to H(2)O(2), killing of DeltacatA conidia by alveolar macrophages and virulence in animals were similar to the killing of conidia by alveolar macrophages and virulence in animals observed for the wild type. In contrast to the Cat1p and CatAp catalases, the mycelial Cat2p enzyme is a bifunctional catalase-peroxidase and is sensitive to heat, metal ions, and detergent. This enzyme, an 82-kDa monomer, is homologous to catalase-peroxidases of several fungi and bacteria. Surprisingly, mycelium of the double Deltacat1Deltacat2 mutant with no catalase activity exhibited only slightly increased sensitivity to H(2)O(2) and was as sensitive to killing by polymorphonuclear neutrophils as mycelium of the wild-type strain. However, this mutant exhibited delayed infection in the rat model of aspergillosis compared to infection by the wild-type strain. These results indicate that conidial catalase is not a virulence factor and that mycelial catalases transiently protect the fungus from the host.
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Affiliation(s)
- Sophie Paris
- Unité des Aspergillus, Département Structure et Dynamique des Gènômes, Institut Pasteur, Paris, France.
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Johnson CH, Prigge JT, Warren AD, McEwen JE. Characterization of an alternative oxidase activity of Histoplasma capsulatum. Yeast 2003; 20:381-8. [PMID: 12673621 DOI: 10.1002/yea.968] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Histoplasma capsulatum possesses a branched mitochondrial electron transport chain, with both cyanide-sensitive and -insensitive oxygen-consuming activities. The latter, carried out by a single subunit enzyme termed 'alternative oxidase', is the focus of this report. AOX1 cDNA clones were isolated and direct evidence that the cDNA ORF encodes functional alternative oxidase is reported. Also reported are the generation of an antiserum to the AOX1 protein product, and specific detection in vivo of the mRNA and protein products of the AOX1 gene. Finally, initial studies of regulation of H. capsulatum AOX1 gene expression demonstrated that RNA abundance was increased after hydrogen peroxide-mediated oxidative stress and after inhibition of mitochondrial electron transport enzymes with antimycin A or sodium cyanide. This pattern of regulation is consistent with the hypothesis that alternative oxidase contributes to survival of H. capsulatum after oxidative or metabolic stress and may be important for virulence of this pathogenic organism. The GenBank Accession Nos for the cDNA sequences reported in this paper are AF133236, AF133237 (AOX1).
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Affiliation(s)
- Clayton H Johnson
- Department of Geriatrics, University of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, AR 72205, USA.
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