1887

Abstract

Recently, several pathogenic fungi were shown to produce extracellular vesicles that contain various components associated with virulence. In the human pathogenic fungus , these components included laccase, an enzyme that catalyses melanin synthesis. Spherical melanin granules have been observed in the cell wall of . Given that melanin granules have dimensions that are comparable to those of extracellular vesicles, and that metazoan organisms produce melanin in vesicular structures known as melanosomes, we investigated the role of vesicles in cryptococcal melanization. Extracellular vesicles melanized when incubated with the melanin precursor -3,4-dihydroxyphenylalanine (-DOPA). The kinetics of substrate incorporation into cells and vesicles was analysed using radiolabelled -DOPA. The results indicated that substrate incorporation was different for cells and isolated vesicles. Acid-generated melanin ghosts stained with lipophilic dyes, implying the presence of associated lipid. A model for melanization is proposed that accounts for these observations and provides a mechanism for the assembly of melanin into relatively uniform spherical particles stacked in an orderly arrangement in the cell wall.

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2009-12-01
2020-04-08
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References

  1. Baker L. G., Specht C. A., Donlin M. J., Lodge J. K.. 2007; Chitosan, the deacetylated form of chitin, is necessary for cell wall integrity in Cryptococcus neoformans. Eukaryot Cell6:855–867
    [Google Scholar]
  2. Banks I. R., Specht C. A., Donlin M. J., Gerik K. J., Levitz S. M., Lodge J. K.. 2005; A chitin synthase and its regulator protein are critical for chitosan production and growth of the fungal pathogen Cryptococcus neoformans. Eukaryot Cell4:1902–1912
    [Google Scholar]
  3. Casadevall A., Steenbergen J. N., Nosanchuk J. D.. 2003; ‘Ready made’ virulence and ‘dual use’ virulence factors in pathogenic environmental fungi – the Cryptococcus neoformans paradigm. Curr Opin Microbiol6:332–337
    [Google Scholar]
  4. Casadevall A., Nosanchuk J. D., Williamson P., Rodrigues M. L.. 2009; Vesicular transport across the fungal cell wall. Trends Microbiol17:158–162
    [Google Scholar]
  5. Egelhaaf S. U., Wehrli E., Müller M., Adrian M., Schurtenberger P.. 1996; Determination of the size distribution of lecithin liposomes: a comparative study using freeze fracture, cryoelectron microscopy, and dynamic light scattering. J Microsc184:214–228
    [Google Scholar]
  6. Eisenman H. C., Nosanchuk J. D., Webber J. B., Emerson R. J., Camesano T. A., Casadevall A.. 2005; Microstructure of cell wall-associated melanin in the human pathogenic fungus Cryptococcus neoformans. Biochemistry44:3683–3693
    [Google Scholar]
  7. Eisenman H. C., Casadevall A., McClelland E. E.. 2007; New insights on the pathogenesis of invasive Cryptococcus neoformans infection. Curr Infect Dis Rep9:457–464
    [Google Scholar]
  8. Felice L. J., Felice J. D., Kissinger P. T.. 1978; Determination of catecholamines in rat brain parts by reverse-phase ion-pair liquid chromatography. J Neurochem31:1461–1465
    [Google Scholar]
  9. Franzen A. J., Cunha M. M., Miranda K., Hentschel J., Plattner H., da Silva M. B., Salgado C. G., de Souza W., Rozental S.. 2008; Ultrastructural characterization of melanosomes of the human pathogenic fungus Fonsecaea pedrosoi. J Struct Biol162:75–84
    [Google Scholar]
  10. Garcia-Rivera J., Casadevall A.. 2001; Melanization of Cryptococcus neoformans reduces its susceptibility to the antimicrobial effects of silver nitrate. Med Mycol39:353–357
    [Google Scholar]
  11. Garcia-Rivera J., Eisenman H. C., Nosanchuk J. D., Aisen P., Zaragoza O., Moadel T., Dadachova E., Casadevall A.. 2005; Comparative analysis of Cryptococcus neoformans acid-resistant particles generated from pigmented cells grown in different laccase substrates. Fungal Genet Biol42:989–998
    [Google Scholar]
  12. Goldman D. L., Khine H., Abadi J., Lindenberg D. J., Pirofski L., Niang R., Casadevall A.. 2001; Serologic evidence for Cryptococcus neoformans infection in early childhood. Pediatrics107:E66
    [Google Scholar]
  13. Graham D. G., Tiffany S. M., Vogel F. S.. 1978; The toxicity of melanin precursors. J Invest Dermatol70:113–116
    [Google Scholar]
  14. Janbon G.. 2004; Cryptococcus neoformans capsule biosynthesis and regulation. FEMS Yeast Res4:765–771
    [Google Scholar]
  15. Kong M., Bhattacharya R., James C., Basu A.. 2005; A statistical approach to estimate the 3D size distribution of spheres from 2D size distributions. Geol Soc Am Bull117:244–249
    [Google Scholar]
  16. McFadden D., Zaragoza O., Casadevall A.. 2006; The capsular dynamics of Cryptococcus neoformans. Trends Microbiol14:497–505
    [Google Scholar]
  17. Nicola A. M., Frases S., Casadevall A.. 2009; Lipophilic dye staining of Cryptococcus neoformans extracellular vesicles and capsule. Eukaryot Cell8:1373–1380
    [Google Scholar]
  18. Nosanchuk J. D., Casadevall A.. 2003; Budding of melanized Cryptococcus neoformans in the presence or absence of l-dopa. Microbiology149:1945–1951
    [Google Scholar]
  19. Nosanchuk J. D., Casadevall A.. 2006; Impact of melanin on microbial virulence and clinical resistance to antimicrobial compounds. Antimicrob Agents Chemother50:3519–3528
    [Google Scholar]
  20. Nosanchuk J. D., Ovalle R., Casadevall A.. 2001; Glyphosate inhibits melanization of Cryptococcus neoformans and prolongs survival of mice after systemic infection. J Infect Dis183:1093–1099
    [Google Scholar]
  21. Panepinto J., Komperda K., Frases S., Park Y. D., Djordjevic J. T., Casadevall A., Williamson P. R.. 2009; Sec6-dependent sorting of fungal extracellular exosomes and laccase of Cryptococcus neoformans. Mol Microbiol71:1165–1176
    [Google Scholar]
  22. Park B. J., Wannemuehler K. A., Marston B. J., Govender N., Pappas P. G., Chiller T. M.. 2009; Estimation of the current global burden of cryptococcal meningitis among persons living with HIV/AIDS. AIDS 23:525–530
    [Google Scholar]
  23. Pavel S.. 1993; Dynamics of melanogenesis intermediates. J Invest Dermatol100:162S–165S
    [Google Scholar]
  24. Perfect J. R.. 2005; Cryptococcus neoformans: a sugar-coated killer with designer genes. FEMS Immunol Med Microbiol45:395–404
    [Google Scholar]
  25. Pukkila-Worley R., Gerrald Q. D., Kraus P. R., Boily M. J., Davis M. J., Giles S. S., Cox G. M., Heitman J., Alspaugh J. A.. 2005; Transcriptional network of multiple capsule and melanin genes governed by the Cryptococcus neoformans cyclic AMP cascade. Eukaryot Cell4:190–201
    [Google Scholar]
  26. Rodrigues M. L., Nimrichter L., Oliveira D. L., Frases S., Miranda K., Zaragoza O., Alvarez M., Nakouzi A., Feldmesser M., Casadevall A.. 2007; Vesicular polysaccharide export in Cryptococcus neoformans is a eukaryotic solution to the problem of fungal trans-cell wall transport. Eukaryot Cell6:48–59
    [Google Scholar]
  27. Rodrigues M. L., Nakayasu E. S., Oliveira D. L., Nimrichter L., Nosanchuk J. D., Almeida I. C., Casadevall A.. 2008; Extracellular vesicles produced by Cryptococcus neoformans contain protein components associated with virulence. Eukaryot Cell7:58–67
    [Google Scholar]
  28. Rosas A. L., Casadevall A.. 1997; Melanization affects susceptibility of Cryptococcus neoformans to heat and cold. FEMS Microbiol Lett153:265–272
    [Google Scholar]
  29. Rosas A. L., Nosanchuk J. D., Gomez B. L., Edens W. A., Henson J. M., Casadevall A.. 2000; Isolation and serological analyses of fungal melanins. J Immunol Methods244:69–80
    [Google Scholar]
  30. Tolleson W. H.. 2005; Human melanocyte biology, toxicology, and pathology. J Environ Sci Health C Environ Carcinog Ecotoxicol Rev23:105–161
    [Google Scholar]
  31. Wang Y., Casadevall A.. 1994; Decreased susceptibility of melanized Cryptococcus neoformans to UV light. Appl Environ Microbiol60:3864–3866
    [Google Scholar]
  32. Wang Y., Aisen P., Casadevall A.. 1995; Cryptococcus neoformans melanin and virulence: mechanism of action. Infect Immun63:3131–3136
    [Google Scholar]
  33. Waterman S. R., Hacham M., Panepinto J., Hu G., Shin S., Williamson P. R.. 2007; Cell wall targeting of laccase of Cryptococcus neoformans during infection of mice. Infect Immun75:714–722
    [Google Scholar]
  34. Zhong J., Frases S., Wang H., Casadevall A., Stark R. E.. 2008; Following fungal melanin biosynthesis with solid-state NMR: biopolymer molecular structures and possible connections to cell-wall polysaccharides. Biochemistry47:4701–4710
    [Google Scholar]
  35. Zhu X., Gibbons J., Garcia-Rivera J., Casadevall A., Williamson P. R.. 2001; Laccase of Cryptococcus neoformans is a cell wall-associated virulence factor. Infect Immun69:5589–5596
    [Google Scholar]
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