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Kumari D, Sachivkina N, Pasrija R. Investigation of the influence of pH and temperature on melanization and survival under oxidative stress in Cryptococcus neoformans. Arch Microbiol 2024; 206:355. [PMID: 39017938 DOI: 10.1007/s00203-024-04080-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 07/04/2024] [Accepted: 07/08/2024] [Indexed: 07/18/2024]
Abstract
Cryptococcus neoformans is an opportunistic pathogenic fungus that produces melanin during infection, an important virulence factor in Cryptococcal infections that enhances the ability of the fungus to resist immune defense. This fungus can synthesize melanin from a variety of substrates, including L-DOPA (L-3,4-dihydroxyphenylalanine). Since melanin protects the fungus from various stress factors such as oxidative, nitrosative, extreme heat and cold stress; we investigated the effects of environmental conditions on melanin production and survival. In this study, we investigated the effects of different pH values (5.6, 7.0 and 8.5) and temperatures (30 °C and 37 °C) on melanization and cell survival using a microtiter plate-based melanin production assay and an oxidative stress assay, respectively. In addition, the efficacy of compounds known to inhibit laccase involved in melanin synthesis, i.e., tunicamycin, β-mercaptoethanol, dithiothreitol, sodium azide and caspofungin on melanization was evaluated and their sensitivity to temperature and pH changes was measured. The results showed that melanin content correlated with pH and temperature changes and that pH 8.5 and 30 °C, were best for melanin production. Besides that, melanin production protects the fungal cells from oxidative stress induced by hydrogen peroxide. Thus, changes in pH and temperature drastically alter melanin production in C. neoformans and it correlates with the fungal survival. Due to the limited antifungal repertoire and the development of resistance in cryptococcal infections, the investigation of environmental conditions in the regulation of melanization and survival of C. neoformans could be useful for future research and clinical phasing.
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Affiliation(s)
- Deepika Kumari
- Department of Biochemistry, Maharshi Dayanand University, Rohtak, 124001, India
| | - Nadezhda Sachivkina
- Department of Microbiology, Peoples' Friendship University of Russia, Moscow, 117198, Russia
| | - Ritu Pasrija
- Department of Biochemistry, Maharshi Dayanand University, Rohtak, 124001, India.
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2
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Stempinski PR, Greengo SD, Casadevall A. Growth on Douglas fir media facilitates Cryptococcus virulence factor production and enhances fungal survival against environmental and immune stressors. Med Mycol 2024; 62:myae068. [PMID: 38982313 DOI: 10.1093/mmy/myae068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 06/27/2024] [Accepted: 07/08/2024] [Indexed: 07/11/2024] Open
Abstract
The yeasts Cryptococcus neoformans and Cryptococcus gattii are fungal pathogens that can be isolated from the environment, including the surfaces of many plants. Cryptococcus gattii caused an outbreak on Vancouver Island, British Columbia beginning in 1999 that has since spread to the Pacific Northwest of the United States. Coastal Douglas fir (Pseudotsuga menziesii) is an important lumber species and a major component of the ecosystems in this area. Previous research has explored Cryptococcus survival and mating on Douglas fir plants and plant-derived material, but no studies have been done on the production of cryptococcal virulence factors by cells grown on those media. Here, we investigated the effects of growth on Douglas fir-derived media on the production of the polysaccharide capsule and melanin, two of the most important cryptococcal virulence factors. We found that while the capsule was mostly unchanged by growth in Douglas fir media compared to cells grown in defined minimal media, Cryptococcus spp. can use substrates present in Douglas fir to synthesize functional and protective melanin. These results suggest mechanisms by which Cryptococcus species may survive in the environment and emphasize the need to explore how association with Douglas fir trees could affect its epidemiology for human cryptococcosis.
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Affiliation(s)
- Piotr R Stempinski
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland 21205, USA
| | - Seth D Greengo
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland 21205, USA
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland 21205, USA
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3
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Baker RP, Liu AZ, Casadevall A. Cell wall melanin impedes growth of the Cryptococcus neoformans polysaccharide capsule by sequestering calcium. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.20.599928. [PMID: 38948764 PMCID: PMC11212976 DOI: 10.1101/2024.06.20.599928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Cryptococcus neoformans has emerged as a frontrunner among deadly fungal pathogens and is particularly life-threatening for many HIV-infected individuals with compromised immunity. Multiple virulence factors contribute to the growth and survival of C. neoformans within the human host, the two most prominent of which are the polysaccharide capsule and melanin. As both of these features are associated with the cell wall, we were interested to explore possible cooperative or competitive interactions between these two virulence factors. Whereas capsule thickness had no effect on the rate at which cells became melanized, build-up of the melanin pigment layer resulted in a concomitant loss of polysaccharide material, leaving melanized cells with significantly thinner capsules than their non-melanized counterparts. When melanin was provided exogenously to cells in a transwell culture system we observed a similar inhibition of capsule growth and maintenance. Our results show that melanin sequesters calcium thereby limiting its availability to form divalent bridges between polysaccharide subunits required for outer capsule assembly. The decreased ability of melanized cells to incorporate exported polysaccharide into the growing capsule correlated with the amount of shed polysaccharide, which could have profound negative impacts on the host immune response. Significance Statement Cryptococcus neoformans is an opportunistic fungal pathogen that presents a significant health risk for immunocompromised individuals. We report an interaction between the two major cryptococcal virulence factors, the polysaccharide capsule and melanin. Melanin impacted the growth and maintenance of the polysaccharide capsule, resulting in loss of capsular material during melanization. Our results suggest that melanin can act as a sink for calcium, thereby limiting its availability to form ionic bridges between polysaccharide chains on the growing surface of the outer capsule. As polysaccharide is continuously exported to support capsule growth, failure of melanized cells to incorporate this material results in a higher concentration of shed polysaccharide in the extracellular milieu, which is expected to interfere with host immunity.
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Qian W, Lu J, Gao C, Liu Q, Li Y, Zeng Q, Zhang J, Wang T, Chen S. Deciphering antifungal and antibiofilm mechanisms of isobavachalcone against Cryptococcus neoformans through RNA-seq and functional analyses. Microb Cell Fact 2024; 23:107. [PMID: 38609931 PMCID: PMC11015616 DOI: 10.1186/s12934-024-02369-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 03/18/2024] [Indexed: 04/14/2024] Open
Abstract
Cryptococcus neoformans has been designated as critical fungal pathogens by the World Health Organization, mainly due to limited treatment options and the prevalence of antifungal resistance. Consequently, the utilization of novel antifungal agents is crucial for the effective treatment of C. neoformans infections. This study exposed that the minimum inhibitory concentration (MIC) of isobavachalcone (IBC) against C. neoformans H99 was 8 µg/mL, and IBC dispersed 48-h mature biofilms by affecting cell viability at 16 µg/mL. The antifungal efficacy of IBC was further validated through microscopic observations using specific dyes and in vitro assays, which confirmed the disruption of cell wall/membrane integrity. RNA-Seq analysis was employed to decipher the effect of IBC on the C. neoformans H99 transcriptomic profiles. Real-time quantitative reverse transcription PCR (RT-qPCR) analysis was performed to validate the transcriptomic data and identify the differentially expressed genes. The results showed that IBC exhibited various mechanisms to impede the growth, biofilm formation, and virulence of C. neoformans H99 by modulating multiple dysregulated pathways related to cell wall/membrane, drug resistance, apoptosis, and mitochondrial homeostasis. The transcriptomic findings were corroborated by the antioxidant analyses, antifungal drug sensitivity, molecular docking, capsule, and melanin assays. In vivo antifungal activity analysis demonstrated that IBC extended the lifespan of C. neoformans-infected Caenorhabditis elegans. Overall, the current study unveiled that IBC targeted multiple pathways simultaneously to inhibit growth significantly, biofilm formation, and virulence, as well as to disperse mature biofilms of C. neoformans H99 and induce cell death.
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Affiliation(s)
- Weidong Qian
- School of Biological and Pharmaceutical Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, P. R. China.
| | - Jiaxing Lu
- School of Biological and Pharmaceutical Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, P. R. China
| | - Chang Gao
- School of Biological and Pharmaceutical Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, P. R. China
| | - Qiming Liu
- School of Biological and Pharmaceutical Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, P. R. China
| | - Yongdong Li
- Ningbo Municipal Center for Disease Control and Prevention, Ningbo, 315010, P. R. China
| | - Qiao Zeng
- School of Biological and Pharmaceutical Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, P. R. China
| | - Jian Zhang
- School of Pharmaceutical Sciences, Shenzhen University Medical School, Shenzhen, 518060, China
| | - Ting Wang
- School of Biological and Pharmaceutical Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, P. R. China
| | - Si Chen
- Department of Immunology, Shenzhen University Medical School, Shenzhen, 518060, China.
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5
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Fernando LD, Zhao W, Gautam I, Ankur A, Wang T. Polysaccharide assemblies in fungal and plant cell walls explored by solid-state NMR. Structure 2023; 31:1375-1385. [PMID: 37597511 PMCID: PMC10843855 DOI: 10.1016/j.str.2023.07.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 06/30/2023] [Accepted: 07/26/2023] [Indexed: 08/21/2023]
Abstract
Structural analysis of macromolecular complexes within their natural cellular environment presents a significant challenge. Recent applications of solid-state NMR (ssNMR) techniques on living fungal cells and intact plant tissues have greatly enhanced our understanding of the structure of extracellular matrices. Here, we selectively highlight the most recent progress in this field. Specifically, we discuss how ssNMR can provide detailed insights into the chemical composition and conformational structure of pectin, and the consequential impact on polysaccharide interactions and cell wall organization. We elaborate on the use of ssNMR data to uncover the arrangement of the lignin-polysaccharide interface and the macrofibrillar structure in native plant stems or during degradation processes. We also comprehend the dynamic structure of fungal cell walls under various morphotypes and stress conditions. Finally, we assess how the combination of NMR with other techniques can enhance our capacity to address unresolved structural questions concerning these complex macromolecular assemblies.
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Affiliation(s)
- Liyanage D Fernando
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Wancheng Zhao
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Isha Gautam
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Ankur Ankur
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Tuo Wang
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA.
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6
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Song W, Yang H, Liu S, Yu H, Li D, Li P, Xing R. Melanin: insights into structure, analysis, and biological activities for future development. J Mater Chem B 2023; 11:7528-7543. [PMID: 37432655 DOI: 10.1039/d3tb01132a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2023]
Abstract
Melanin, a widely distributed pigment found in various organisms, possesses distinct structures that can be classified into five main types: eumelanin (found in animals and plants), pheomelanin (found in animals and plants), allomelanin (found in plants), neuromelanin (found in animals), and pyomelanin (found in fungi and bacteria). In this review, we present an overview of the structure and composition of melanin, as well as the various spectroscopic identification methods that can be used, such as Fourier transform infrared (FTIR) spectroscopy, electron spin resonance (ESR) spectroscopy, and thermogravimetric analysis (TGA). We also provide a summary of the extraction methods of melanin and its diverse biological activities, including antibacterial properties, anti-radiation effects, and photothermal effects. The current state of research on natural melanin and its potential for further development is discussed. In particular, the review provides a comprehensive summary of the analysis methods used to determine melanin species, offering valuable insights and references for future research. Overall, this review aims to provide a thorough understanding of the concept and classification of melanin, its structure, physicochemical properties, and structural identification methods, as well as its various applications in the field of biology.
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Affiliation(s)
- Wen Song
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
- University of Chinese Academy of Sciences, Beijing 100000, China
- Department of Food Science & Technology, Faculty of Science, National University of Singapore, 117546, Singapore.
| | - Haoyue Yang
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
| | - Song Liu
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
- Laboratory for Marine Drugs and Bioproducts, Pilot National Laboratory for Marine Science and Technology (Qingdao), No. 7 Nanhai Road, Qingdao 266000, China
| | - Huahua Yu
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
- Laboratory for Marine Drugs and Bioproducts, Pilot National Laboratory for Marine Science and Technology (Qingdao), No. 7 Nanhai Road, Qingdao 266000, China
| | - Dan Li
- Department of Food Science & Technology, Faculty of Science, National University of Singapore, 117546, Singapore.
| | - Pengcheng Li
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
- Laboratory for Marine Drugs and Bioproducts, Pilot National Laboratory for Marine Science and Technology (Qingdao), No. 7 Nanhai Road, Qingdao 266000, China
| | - Ronge Xing
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
- Laboratory for Marine Drugs and Bioproducts, Pilot National Laboratory for Marine Science and Technology (Qingdao), No. 7 Nanhai Road, Qingdao 266000, China
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Ma Y, Yang L, Jiang M, Zhao X, Xue P. Connecting Cryptococcal Meningitis and Gut Microbiome. Int J Mol Sci 2023; 24:13515. [PMID: 37686320 PMCID: PMC10487799 DOI: 10.3390/ijms241713515] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 08/27/2023] [Accepted: 08/30/2023] [Indexed: 09/10/2023] Open
Abstract
Fungal pathogens of the Cryptococcus neoformans species complex (C. neoformans SC) are a major cause of fungal meningitis in immunocompromised individuals. As with other melanotic microorganisms associated with human diseases, the cell-wall-associated melanin of C. neoformans SC is a major virulence factor that contributes to its ability to evade host immune responses. The levels of melanin substrate and the regulation of melanin formation could be influenced by the microbiota-gut-brain axis. Moreover, recent studies show that C. neoformans infections cause dysbiosis in the human gut microbiome. In this review, we discuss the potential association between cryptococcal meningitis and the gut microbiome. Additionally, the significant potential of targeting the gut microbiome in the diagnosis and treatment of this debilitating disease is emphasized.
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Affiliation(s)
- Yuanyuan Ma
- Nantong Key Laboratory of Environmental Toxicology, Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong 226019, China; (Y.M.); (M.J.)
| | - Liang Yang
- School of Medicine, Southern University of Science and Technology, Shenzhen 518055, China;
| | - Mengna Jiang
- Nantong Key Laboratory of Environmental Toxicology, Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong 226019, China; (Y.M.); (M.J.)
| | - Xinyuan Zhao
- Nantong Key Laboratory of Environmental Toxicology, Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong 226019, China; (Y.M.); (M.J.)
| | - Peng Xue
- Nantong Key Laboratory of Environmental Toxicology, Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong 226019, China; (Y.M.); (M.J.)
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8
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Jacobs E, Chrissian C, Rankin-Turner S, Wear M, Camacho E, Broderick NA, McMeniman CJ, Stark RE, Casadevall A. Cuticular profiling of insecticide resistant Aedes aegypti. Sci Rep 2023; 13:10154. [PMID: 37349387 PMCID: PMC10287657 DOI: 10.1038/s41598-023-36926-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 06/12/2023] [Indexed: 06/24/2023] Open
Abstract
Insecticides have made great strides in reducing the global burden of vector-borne disease. Nonetheless, serious public health concerns remain because insecticide-resistant vector populations continue to spread globally. To circumvent insecticide resistance, it is essential to understand all contributing mechanisms. Contact-based insecticides are absorbed through the insect cuticle, which is comprised mainly of chitin polysaccharides, cuticular proteins, hydrocarbons, and phenolic biopolymers sclerotin and melanin. Cuticle interface alterations can slow or prevent insecticide penetration in a phenomenon referred to as cuticular resistance. Cuticular resistance characterization of the yellow fever mosquito, Aedes aegypti, is lacking. In the current study, we utilized solid-state nuclear magnetic resonance spectroscopy, gas chromatography/mass spectrometry, and transmission electron microscopy to gain insights into the cuticle composition of congenic cytochrome P450 monooxygenase insecticide resistant and susceptible Ae. aegypti. No differences in cuticular hydrocarbon content or phenolic biopolymer deposition were found. In contrast, we observed cuticle thickness of insecticide resistant Ae. aegypti increased over time and exhibited higher polysaccharide abundance. Moreover, we found these local cuticular changes correlated with global metabolic differences in the whole mosquito, suggesting the existence of novel cuticular resistance mechanisms in this major disease vector.
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9
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Aranda C, Méndez I, Barra PJ, Hernández-Montiel L, Fallard A, Tortella G, Briones E, Durán P. Melanin Induction Restores the Pathogenicity of Gaeumannomyces graminis var. tritici in Wheat Plants. J Fungi (Basel) 2023; 9:jof9030350. [PMID: 36983518 PMCID: PMC10058861 DOI: 10.3390/jof9030350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/02/2023] [Accepted: 03/03/2023] [Indexed: 03/18/2023] Open
Abstract
One of the most challenging aspects of long-term research based on microorganisms is the maintenance of isolates under ex situ conditions, particularly the conservation of phytopathological characteristics. Our research group has worked for more than 10 years with Gaumannomyces graminis var. tritici (Ggt), the main biotic factor affecting wheat. In this sense we preserved the microorganisms in oil overlaid. However, several strains preserved for a long time lost their pathogenicity. These strains show white and non-infective mycelia. In this sense, we hypothesized that this is attributable to low melanin content. Melanin is a natural pigment mainly involved in UV protection, desiccation, salinity, oxidation, and fungal pathogenicity. Therefore, understanding the melanin role on Ggt pathogenicity is fundamental to developing melanin activation strategies under laboratory studies. In this study, we induce melanin activation by UV-A light chamber, 320 to 400 nm (T1) and temperature changes of 30 °C, 15 °C, and 20 °C (T2). Fungal pathogenicity was evaluated by determination of blackening roots and Ggt was quantified by real-time PCR in inoculated wheat plants. Results revealed that Ggt grown under UV-A (T1) conditions showed around 40% higher melanin level with a concomitant effect on root infection (98% of blackened roots) and 4-fold more Ggt genome copy number compared with the control (non-infective mycelia) being T1, a more inductor factor compared with T2. These findings would support the role of melanin in pathogenicity in darkly pigmented fungi such as Ggt and could serve as a basis for activating pathogenicity under laboratory conditions.
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Affiliation(s)
- Camila Aranda
- Programa de Doctorado en Ciencias de Recursos Naturales, Universidad de La Frontera, Temuco 4811230, Chile
- Biocontrol Research Laboratory, Universidad de La Frontera, Temuco 4811230, Chile
| | - Isabel Méndez
- Programa de Doctorado en Ciencias de Recursos Naturales, Universidad de La Frontera, Temuco 4811230, Chile
- Biocontrol Research Laboratory, Universidad de La Frontera, Temuco 4811230, Chile
| | - Patricio Javier Barra
- Biocontrol Research Laboratory, Universidad de La Frontera, Temuco 4811230, Chile
- Scientific and Technological Bioresource Nucleus, Universidad de La Frontera, Temuco 4811230, Chile
| | - Luis Hernández-Montiel
- Nanotechnology and Microbial Biocontrol Group, Centro de Investigaciones Biológicas del Noroeste, Av. Politécnico Nacional 195, Col. Playa Palo de Santa Rita Sur, La Paz 23090, Mexico
| | - Ana Fallard
- Biocontrol Research Laboratory, Universidad de La Frontera, Temuco 4811230, Chile
| | - Gonzalo Tortella
- Scientific and Technological Bioresource Nucleus, Universidad de La Frontera, Temuco 4811230, Chile
| | - Evelyn Briones
- Biocontrol Research Laboratory, Universidad de La Frontera, Temuco 4811230, Chile
| | - Paola Durán
- Biocontrol Research Laboratory, Universidad de La Frontera, Temuco 4811230, Chile
- Scientific and Technological Bioresource Nucleus, Universidad de La Frontera, Temuco 4811230, Chile
- Facultad de Ciencias Agropecuarias y Medioambiente, Departamento de Producción Agropecuaria, Universidad de La Frontera, Temuco 4811230, Chile
- Correspondence:
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Juravel E, Polacheck I, Isaacson B, Dagan A, Korem M. The Distinction between Dematiaceous Molds and Non-Dematiaceous Fungi in Clinical and Spiked Samples Treated with Hydrogen Peroxide Using Direct Fluorescence Microscopy. J Fungi (Basel) 2023; 9:jof9020227. [PMID: 36836341 PMCID: PMC9967646 DOI: 10.3390/jof9020227] [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: 01/12/2023] [Revised: 02/01/2023] [Accepted: 02/07/2023] [Indexed: 02/11/2023] Open
Abstract
Dematiaceous fungi are pigmented molds with a high content of melanin in their cell walls that can cause fatal infections in immunocompromised hosts. Direct microscopy is the main method for the rapid diagnosis of dematiaceous fungi in clinical specimens. However, it is often difficult to distinguish their hyphae from non-dematiaceous hyphae and yeast pseudohyphae. Our aim was to develop a fluorescence staining method that targets melanin for the detection of dematiaceous molds in clinical specimens. Glass slide smears of clinical samples and sterile bronchoalveolar lavage spiked with dematiaceous and non-dematiaceous fungi were treated with hydrogen peroxide, and digital images were recorded using direct microscopy with different fluorescent filters. The images of fungi were compared for their fluorescence intensity using the NIS-Elements software. The fluorescent signal between dematiaceous and non-dematiaceous fungi demonstrated a markedly increased mean intensity for dematiaceous molds following hydrogen peroxide treatment (7510.3 ± 10,427.6 vs. 0.3 ± 3.1, respectively, p < 0.0001). No fluorescent signal was detected in the absence of hydrogen peroxide. "Staining" fungal clinical specimens with hydrogen peroxide, followed by fluorescence microscopy examination, can differentiate between dematiaceous and non-dematiaceous fungi. This finding can be used for the detection of dematiaceous molds in clinical specimens and enables the early and appropriate treatment of infections.
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Affiliation(s)
- Elchanan Juravel
- Department of Internal Medicine, Hadassah Medical Center and Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112101, Israel
| | - Itzhack Polacheck
- Department of Clinical Microbiology and Infectious Diseases, Hadassah Medical Center and Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112101, Israel
| | - Batya Isaacson
- The Concern Foundation Laboratories at the Lautenberg Center for Immunology and Cancer Research, The Hebrew University Medical School, IMRIC, Jerusalem 9112102, Israel
| | - Arie Dagan
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, The Hebrew University Medical School, Jerusalem 9112102, Israel
| | - Maya Korem
- Department of Clinical Microbiology and Infectious Diseases, Hadassah Medical Center and Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112101, Israel
- Correspondence: ; Tel.: +972-50-8573173; Fax: +972-2-6419545
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Solid-state NMR molecular snapshots of Aspergillus fumigatus cell wall architecture during a conidial morphotype transition. Proc Natl Acad Sci U S A 2023; 120:e2212003120. [PMID: 36719915 PMCID: PMC9963690 DOI: 10.1073/pnas.2212003120] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
While establishing an invasive infection, the dormant conidia of Aspergillus fumigatus transit through swollen and germinating stages, to form hyphae. During this morphotype transition, the conidial cell wall undergoes dynamic remodeling, which poses challenges to the host immune system and antifungal drugs. However, such cell wall reorganization during conidial germination has not been studied so far. Here, we explored the molecular rearrangement of Aspergillus fumigatus cell wall polysaccharides during different stages of germination. We took advantage of magic-angle spinning NMR to investigate the cell wall polysaccharides, without employing any destructive method for sample preparation. The breaking of dormancy was associated with a significant change in the molar ratio between the major polysaccharides β-1,3-glucan and α-1,3-glucan, while chitin remained equally abundant. The use of various polarization transfers allowed the detection of rigid and mobile polysaccharides; the appearance of mobile galactosaminogalactan was a molecular hallmark of germinating conidia. We also report for the first time highly abundant triglyceride lipids in the mobile matrix of conidial cell walls. Water to polysaccharides polarization transfers revealed an increased surface exposure of glucans during germination, while chitin remained embedded deeper in the cell wall, suggesting a molecular compensation mechanism to keep the cell wall rigidity. We complement the NMR analysis with confocal and atomic force microscopies to explore the role of melanin and RodA hydrophobin on the dormant conidial surface. Exemplified here using Aspergillus fumigatus as a model, our approach provides a powerful tool to decipher the molecular remodeling of fungal cell walls during their morphotype switching.
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Jacobs E, Chrissian C, Rankin-Turner S, Wear M, Camacho E, Scott JG, Broderick NA, McMeniman CJ, Stark RE, Casadevall A. Cuticular profiling of insecticide resistant Aedes aegypti. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.13.523989. [PMID: 36712033 PMCID: PMC9882251 DOI: 10.1101/2023.01.13.523989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Insecticides have made great strides in reducing the global burden of vector-borne disease. Nonetheless, serious public health concerns remain because insecticide-resistant vector populations continue to spread globally. To circumvent insecticide resistance, it is essential to understand all contributing mechanisms. Contact-based insecticides are absorbed through the insect cuticle, which is comprised mainly of chitin polysaccharides, cuticular proteins, hydrocarbons, and phenolic biopolymers sclerotin and melanin. Cuticle interface alterations can slow or prevent insecticide penetration in a phenomenon referred to as cuticular resistance. Cuticular resistance characterization of the yellow fever mosquito, Aedes aegypti , is lacking. In the current study, we utilized solid-state Nuclear Magnetic Resonance (ssNMR) spectroscopy, gas chromatography/mass spectrometry (GC-MS), and transmission electron microscopy (TEM) to gain insights into the cuticle composition of congenic cytochrome P450 monooxygenase insecticide resistant and susceptible Ae. aegypti . No differences in cuticular hydrocarbon content or phenolic biopolymer deposition were found. In contrast, we observed cuticle thickness of insecticide resistant Ae. aegypti increased over time and exhibited higher polysaccharide abundance. Moreover, we found these local cuticular changes correlated with global metabolic differences in the whole mosquito, suggesting the existence of novel cuticular resistance mechanisms in this major disease vector.
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Affiliation(s)
| | - Christine Chrissian
- The City College of New York and CUNY Institute for Macromolecular Assemblies
| | | | - Maggie Wear
- Johns Hopkins University Bloomberg School of Public Health
| | - Emma Camacho
- Johns Hopkins University Bloomberg School of Public Health
| | | | | | | | - Ruth E. Stark
- The City College of New York and CUNY Institute for Macromolecular Assemblies
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13
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Smith DFQ, Mudrak NJ, Zamith-Miranda D, Honorato L, Nimrichter L, Chrissian C, Smith B, Gerfen G, Stark RE, Nosanchuk JD, Casadevall A. Melanization of Candida auris Is Associated with Alteration of Extracellular pH. J Fungi (Basel) 2022; 8:1068. [PMID: 36294632 PMCID: PMC9604884 DOI: 10.3390/jof8101068] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 10/05/2022] [Accepted: 10/07/2022] [Indexed: 11/29/2022] Open
Abstract
Candida auris is a recently emerged global fungal pathogen, which causes life-threatening infections, often in healthcare settings. C. auris infections are worrisome because the fungus is often resistant to multiple antifungal drug classes. Furthermore, C. auris forms durable and difficult to remove biofilms. Due to the relatively recent, resilient, and resistant nature of C. auris, we investigated whether it produces the common fungal virulence factor melanin. Melanin is a black-brown pigment typically produced following enzymatic oxidation of aromatic precursors, which promotes fungal virulence through oxidative stress resistance, mammalian immune response evasion, and antifungal peptide and pharmaceutical inactivation. We found that certain strains of C. auris oxidized L-DOPA and catecholamines into melanin. Melanization occurred extracellularly in a process mediated by alkalinization of the extracellular environment, resulting in granule-like structures that adhere to the fungus' external surface. C. auris had relatively high cell surface hydrophobicity, but there was no correlation between hydrophobicity and melanization. Melanin protected the fungus from oxidative damage, but we did not observe a protective role during infection of macrophages or Galleria mellonella larvae. In summary, C. auris alkalinizes the extracellular medium, which promotes the non-enzymatic oxidation of L-DOPA to melanin that attaches to its surface, thus illustrating a novel mechanism for fungal melanization.
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Affiliation(s)
- Daniel F. Q. Smith
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Nathan J. Mudrak
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
- Krieger School of Arts & Science, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Daniel Zamith-Miranda
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA
- Division of Infectious Diseases, Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA
| | - Leandro Honorato
- Laboratório de Glicobiologia de Eucariotos, Departamento de Microbiologia Geral, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
| | - Leonardo Nimrichter
- Laboratório de Glicobiologia de Eucariotos, Departamento de Microbiologia Geral, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
| | - Christine Chrissian
- Department of Chemistry and Biochemistry, City College of New York and CUNY Institute for Macromolecular Assemblies, The City University of New York, New York, NY 10031, USA
| | - Barbara Smith
- Institute for Basic Biomedical Sciences Microscope Facility, The Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Gary Gerfen
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA
| | - Ruth E. Stark
- Department of Chemistry and Biochemistry, City College of New York and CUNY Institute for Macromolecular Assemblies, The City University of New York, New York, NY 10031, USA
| | - Joshua D. Nosanchuk
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA
- Division of Infectious Diseases, Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA
| | - Arturo Casadevall
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
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14
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Lino V, Manini P. Dihydroxynaphthalene-Based Allomelanins: A Source of Inspiration for Innovative Technological Materials. ACS OMEGA 2022; 7:15308-15314. [PMID: 35571811 PMCID: PMC9096960 DOI: 10.1021/acsomega.2c00641] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 04/12/2022] [Indexed: 06/15/2023]
Abstract
Melanins are a wide class of natural pigments biosynthesized by different kinds of living organisms throughout all of the life domains, from bacteria to fungi, plants, and mammals. The biological functions played by these natural pigments are different (i.e., camouflage, radioprotection, thermoregulation) and ascribable to a peculiar set of physical-chemical properties making melanins a unique class of biopolymers. Among these, allomelanins from 1,8-dihydroxynaphthalene (1,8-DHNmel) produced by some Ascomycetes have recently attracted particular interest for their robustness and ability to protect fungi against both hostile (i.e., attack from fungicidal agents) and extreme (i.e., high energy radiations) environments. Starting from this background, in this mini-review we offer a panorama of the recent advances on the oxidative chemistry of 1,8-DHN leading to the formation of allomelanin mimics with tailored structural and functional properties for technological applications.
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Affiliation(s)
- Valeria Lino
- Scuola
Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
- Department
of Chemical Sciences, University of Napoli
Federico II, via Cintia
4, I-80126 Napoli, Italy
| | - Paola Manini
- Department
of Chemical Sciences, University of Napoli
Federico II, via Cintia
4, I-80126 Napoli, Italy
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15
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Erives VH, Munzen ME, Zamith-Miranda D, Hernandez H, Manepalli S, Nguyen LN, Hamed MF, Nosanchuk JD, Martinez LR. Methamphetamine Enhances Cryptococcus neoformans Melanization, Antifungal Resistance, and Pathogenesis in a Murine Model of Drug Administration and Systemic Infection. Infect Immun 2022; 90:e0009122. [PMID: 35357221 PMCID: PMC9022586 DOI: 10.1128/iai.00091-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 03/02/2022] [Indexed: 11/20/2022] Open
Abstract
Methamphetamine (METH) is a major public health and safety problem in the United States. Chronic METH abuse is associated with a 2-fold-higher risk of HIV infection and, possibly, additional infections, particularly those that enter through the respiratory tract or skin. Cryptococcus neoformans is an encapsulated opportunistic yeast-like fungus that is a relatively frequent cause of meningoencephalitis in immunocompromised patients, especially in individuals with AIDS. C. neoformans melanizes during mammalian infection in a process that presumably uses host-supplied compounds such as catecholamines. l-3,4-Dihydroxyphenylalanine (l-Dopa) is a natural catecholamine that is frequently used to induce melanization in C. neoformans. l-Dopa-melanized cryptococci manifest resistance to radiation, phagocytosis, detergents, and heavy metals. Using a systemic mouse model of infection and in vitro assays to critically assess the impact of METH on C. neoformans melanization and pathogenesis, we demonstrated that METH-treated mice infected with melanized yeast cells showed increased fungal burdens in the blood and brain, exacerbating mortality. Interestingly, analyses of cultures of METH-exposed cryptococci supplemented with l-Dopa revealed that METH accelerates fungal melanization, an event of adaptation to external stimuli that can be advantageous to the fungus during pathogenesis. Our findings provide novel evidence of the impact of METH abuse on host homeostasis and increased permissiveness to opportunistic microorganisms.
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Affiliation(s)
- Victor H. Erives
- Department of Biological Sciences, The Border Biomedical Research Center, The University of Texas at El Paso, El Paso, Texas, USA
| | - Melissa E. Munzen
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Daniel Zamith-Miranda
- Department of Medicine (Division of Infectious Diseases), Albert Einstein College of Medicine, Bronx, New York, USA
| | - Hazael Hernandez
- Department of Biological Sciences, The Border Biomedical Research Center, The University of Texas at El Paso, El Paso, Texas, USA
- Texas Tech University Health Sciences Center, Lubbock, Texas, USA
| | - Swetha Manepalli
- Department of Biomedical Sciences, Long Island University-Post, Brookville, New York, USA
| | - Long N. Nguyen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Mohamed F. Hamed
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
- Department of Pathology, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt
| | - Joshua D. Nosanchuk
- Department of Medicine (Division of Infectious Diseases), Albert Einstein College of Medicine, Bronx, New York, USA
| | - Luis R. Martinez
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
- Department of Biomedical Sciences, Long Island University-Post, Brookville, New York, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA
- Center for Immunology and Transplantation, University of Florida, Gainesville, Florida, USA
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, Florida, USA
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