Differential Antifungal Activity of Human and Cryptococcal Melanins with Structural Discrepancies
Melanin is a pigment found in all biological kingdoms, and plays a key role in protection against ultraviolet radiation, oxidizing agents, and ionizing radiation damage. Melanin exerts an antimicrobial activity against bacteria, fungi, and parasites. We demonstrated an antifungal activity of synthet...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2017-07-01
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| Series: | Frontiers in Microbiology |
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| Online Access: | http://journal.frontiersin.org/article/10.3389/fmicb.2017.01292/full |
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| author | Néstor Correa Néstor Correa Néstor Correa Cristian Covarrubias Paula I. Rodas Germán Hermosilla Verónica R. Olate Verónica R. Olate Cristián Valdés Wieland Meyer Fabien Magne Cecilia V. Tapia Cecilia V. Tapia |
| author_facet | Néstor Correa Néstor Correa Néstor Correa Cristian Covarrubias Paula I. Rodas Germán Hermosilla Verónica R. Olate Verónica R. Olate Cristián Valdés Wieland Meyer Fabien Magne Cecilia V. Tapia Cecilia V. Tapia |
| author_sort | Néstor Correa |
| collection | DOAJ |
| description | Melanin is a pigment found in all biological kingdoms, and plays a key role in protection against ultraviolet radiation, oxidizing agents, and ionizing radiation damage. Melanin exerts an antimicrobial activity against bacteria, fungi, and parasites. We demonstrated an antifungal activity of synthetic and human melanin against Candida sp. The members of the Cryptococcus neoformans and C. gattii species complexes are capsulated yeasts, which cause cryptococcosis. For both species melanin is an important virulence factor. To evaluate if cryptococcal and human melanins have antifungal activity against Cryptococcus species they both were assayed for their antifungal properties and physico-chemical characters. Melanin extracts from human hair and different strains of C. neoformans (n = 4) and C. gattii (n = 4) were investigated. The following minimum inhibitory concentrations were found for different melanins against C. neoformans and C. gattii were (average/range): 13.7/(7.8–15.6) and 19.5/(15.6–31.2) μg/mL, respectively, for human melanin; 273.4/(125–>500) and 367.2/(125.5–>500) μg/mL for C. neoformans melanin and 125/(62.5–250) and 156.2/(62–250) μg/mL for C. gattii melanin. Using Scanning Electron Microscopy we observed that human melanin showed a compact conformation and cryptococcal melanins exposed an amorphous conformation. Infrared spectroscopy (FTIR) showed some differences in the signals related to C-C bonds of the aromatic ring of the melanin monomers. High Performance Liquid Chromatography established differences in the chromatograms of fungal melanins extracts in comparison with human and synthetic melanin, particularly in the retention time of the main compound of fungal melanin extracts and also in the presence of minor unknown compounds. On the other hand, MALDI-TOF-MS analysis showed slight differences in the spectra, specifically the presence of a minor intensity ion in synthetic and human melanin, as well as in some fungal melanin extracts. We conclude that human melanin is more active than the two fungal melanins against Cryptococcus. Although some physico-chemical differences were found, they do not explain the differences in the antifungal activity against Cryptococcus of human and cryptococcal melanins. More detailed studies on the structure should be considered to associate structure and antifungal activity. |
| first_indexed | 2024-12-10T14:06:14Z |
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| institution | Directory Open Access Journal |
| issn | 1664-302X |
| language | English |
| last_indexed | 2024-12-10T14:06:14Z |
| publishDate | 2017-07-01 |
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| series | Frontiers in Microbiology |
| spelling | doaj.art-2803cf9239e143ccb1f11560d945590a2022-12-22T01:45:39ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2017-07-01810.3389/fmicb.2017.01292279335Differential Antifungal Activity of Human and Cryptococcal Melanins with Structural DiscrepanciesNéstor Correa0Néstor Correa1Néstor Correa2Cristian Covarrubias3Paula I. Rodas4Germán Hermosilla5Verónica R. Olate6Verónica R. Olate7Cristián Valdés8Wieland Meyer9Fabien Magne10Cecilia V. Tapia11Cecilia V. Tapia12Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de ChileSantiago, ChileFacultad de Medicina Clínica Alemana, Universidad del DesarrolloSantiago, ChileEscuela de Tecnología Médica, Universidad San SebastiánSantiago, ChileLaboratorio de Nanomateriales, Facultad de Odontología, Universidad de ChileSantiago, ChileCenter for Integrative Medicine and Innovative Science, Facultad de Medicina, Universidad Andres BelloSantiago, ChilePrograma de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de ChileSantiago, ChileInstituto de Química de Recursos Naturales, Universidad de TalcaTalca, ChileCenter for Systems Biotechnology, Fraunhofer Chile ResearchSantiago, ChileLaboratorio de Fisicoquímica, Universidad de TalcaTalca, ChileMolecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Marie Bashir Institute for Infectious Diseases and Biosecurity, Sydney Medical School – Westmead Hospital, Westmead Institute for Medical Research, University of Sydney, SydneyNSW, AustraliaPrograma de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de ChileSantiago, ChilePrograma de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de ChileSantiago, Chile0Laboratorio de Clínica DávilaSantiago, ChileMelanin is a pigment found in all biological kingdoms, and plays a key role in protection against ultraviolet radiation, oxidizing agents, and ionizing radiation damage. Melanin exerts an antimicrobial activity against bacteria, fungi, and parasites. We demonstrated an antifungal activity of synthetic and human melanin against Candida sp. The members of the Cryptococcus neoformans and C. gattii species complexes are capsulated yeasts, which cause cryptococcosis. For both species melanin is an important virulence factor. To evaluate if cryptococcal and human melanins have antifungal activity against Cryptococcus species they both were assayed for their antifungal properties and physico-chemical characters. Melanin extracts from human hair and different strains of C. neoformans (n = 4) and C. gattii (n = 4) were investigated. The following minimum inhibitory concentrations were found for different melanins against C. neoformans and C. gattii were (average/range): 13.7/(7.8–15.6) and 19.5/(15.6–31.2) μg/mL, respectively, for human melanin; 273.4/(125–>500) and 367.2/(125.5–>500) μg/mL for C. neoformans melanin and 125/(62.5–250) and 156.2/(62–250) μg/mL for C. gattii melanin. Using Scanning Electron Microscopy we observed that human melanin showed a compact conformation and cryptococcal melanins exposed an amorphous conformation. Infrared spectroscopy (FTIR) showed some differences in the signals related to C-C bonds of the aromatic ring of the melanin monomers. High Performance Liquid Chromatography established differences in the chromatograms of fungal melanins extracts in comparison with human and synthetic melanin, particularly in the retention time of the main compound of fungal melanin extracts and also in the presence of minor unknown compounds. On the other hand, MALDI-TOF-MS analysis showed slight differences in the spectra, specifically the presence of a minor intensity ion in synthetic and human melanin, as well as in some fungal melanin extracts. We conclude that human melanin is more active than the two fungal melanins against Cryptococcus. Although some physico-chemical differences were found, they do not explain the differences in the antifungal activity against Cryptococcus of human and cryptococcal melanins. More detailed studies on the structure should be considered to associate structure and antifungal activity.http://journal.frontiersin.org/article/10.3389/fmicb.2017.01292/fullmelaninantifungal activitycryptococcosisCryptococcus spp.physical-chemical |
| spellingShingle | Néstor Correa Néstor Correa Néstor Correa Cristian Covarrubias Paula I. Rodas Germán Hermosilla Verónica R. Olate Verónica R. Olate Cristián Valdés Wieland Meyer Fabien Magne Cecilia V. Tapia Cecilia V. Tapia Differential Antifungal Activity of Human and Cryptococcal Melanins with Structural Discrepancies Frontiers in Microbiology melanin antifungal activity cryptococcosis Cryptococcus spp. physical-chemical |
| title | Differential Antifungal Activity of Human and Cryptococcal Melanins with Structural Discrepancies |
| title_full | Differential Antifungal Activity of Human and Cryptococcal Melanins with Structural Discrepancies |
| title_fullStr | Differential Antifungal Activity of Human and Cryptococcal Melanins with Structural Discrepancies |
| title_full_unstemmed | Differential Antifungal Activity of Human and Cryptococcal Melanins with Structural Discrepancies |
| title_short | Differential Antifungal Activity of Human and Cryptococcal Melanins with Structural Discrepancies |
| title_sort | differential antifungal activity of human and cryptococcal melanins with structural discrepancies |
| topic | melanin antifungal activity cryptococcosis Cryptococcus spp. physical-chemical |
| url | http://journal.frontiersin.org/article/10.3389/fmicb.2017.01292/full |
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