Abstract
Cryptococcus neoformans is a free-living fungus that is primarily found in soils contaminated with avian excreta. Recent studies have shown that C. neoformans can synthesize melanins or melanin-like compounds in avian excreta. Melanization has been associated with protection of C. neoformans against harsh environmental conditions, such as ultraviolet radiation and extremes of temperature. In this study we examined whether melanization can protect C. neoformans against enzymatic degradation. Our results demonstrated that in vitro melanization decreases the susceptibility of C. neoformans to hydrolytic enzymes. This suggests a role for melanin in protection of C. neoformans against enzymatic degradation by antagonistic microbes in the environment.
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References
Mitchell JH, Perfect JR. Cryptococcosis in the era of AIDS-100 years after the discovery of Cryptococcus neoformans. Clin Microbiol Rev 1995; 8: 515-548.
Levitz SM. The ecology of Cryptococcus neoformans and the epidemiology of cryptococcosis. Rev Infect Dis 1991; 13: 1163-1169.
Ruiz A, Fromtling RA, Bulmer GS. Distribution of Cyptococcus neoformans in a natural site. Infect Immun 1981; 31: 560-563.
Emmons CW. Isolation of Cryptococcus neoformans from soil. J Bacteriol 1951; 62: 685-690.
Emmons CW. Saprophytic sources of Cryptococcus neoformans associated with the pigeon (Columba livia). Am J Hyg 1955; 62: 227-232.
Ishaq CM, Bulmer GS, Felton FG. An evaluation of various environmental factors affecting the propagation of Cyptococcus neoformans. Mycophatologia 1968; 35: 81-90.
Neilson JB, Ivey MH, Bulmer GS. Cryptococcus neoformans: pseudohyphal forms surviving culture with Acanthamoeba polyphaga. Infect Immun 1978; 20: 262-266.
Bunting LA, Neilson JB, Bulmer GS. Cryptococcus neoformans: gastronomic delight of a soil ameba. Sabouradia 1979; 17: 225-232.
Ruiz A, Neilson JB, Bulmer GS. Control of Cryptococcus neoformans in nature by biotic factors. Sabouradia 1982; 20: 21-29.
Nosanchuk JD, Rudolph J, Rosas AL, Casadevall A. Evidence that Cryptococcus neoformans is melanized in pigeon excreta: implications for pathogenesis. Infect Immun 1999; 67: 5477-5479.
Wang Y, Casadevall A. Decreased susceptibility of melanized Cryptococcus neoformans to UV light. Appl Environ Microbiol 1994; 60: 3864-3866.
Rosas ÁL, Casadevall A. Melanization affects susceptibility of Cryptococcus neoformans to heat and cold. FEMS Microbiol Lett 1997; 153: 265-272 [published erratum appears in FEMS Microbiol Lett 1997; 156: 171].
Wang Y, Aisen P, Casadevall A. Cyptococcus neoformans melanin and virulence: mechanism of action. Infect Immun 1995; 63: 3131-3136.
Werner-Washbume M, Braun E, Johnston GC, Singer RA. Stationary phase in the yeast, Saccharomyces cerevisiae. Microbiol Rev 1993; 57: 383-401.
Polacheck I, Platt Y, Aronovich J. Catecholamines and virulence of Cryptococcus neoformans. Infect Immun 1990; 58: 2919-2922.
Lockwood JL. Lysis of mycelium of plant-pathogenic fungi by natural soil. Phytopathology 1960; 50: 787-789.
Linderman RG, Tousson TA. Behavior of albino chlamydospores of Thielaviopsis basicola. Phytopathology 1966: 56: 887.
Potgieter HJ, Alexander M. Susceptibility and resistance of several fungi to microbial lysis. J Bacterol 1966; 91: 1526-1532.
Bloomfield BJ, Alexander M. Melanins and resistance of fungi to lysis. J Bacteriol 1967; 93: 1276-1280.
Kuo M-J, Alexander M. Inhibition of the lysis of fungi by melanins. J Bacteriol 1967; 94: 624-629.
Bull AT. Kinetics of cellulase inactivation by melanin. Enzymologia 1970; 39: 333-347.
Bull AT. Inhibition of polysaccharases by melanin. Enzyme inhibition in relation to mycolysis. Arch Biochem Biophys 1970; 137: 345-356.
Doering TL, Nosanchuk JD, Roberts WK, Casadevall A. Melanin as a potent cryptococcal defence against microbicidal proteins. Med Mycol 1999; 37: 175-181.
Larsson BS. Interaction between chemicals and melanin. Pigment Cell Res 1993; 6: 127-1333.
Akino M. Further studies on the inhibition of hyaluronidase by melanin. I. Factors affecting the inhibition. Japan J Zool 1960; 12: 527-538.
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Rosas, Á.L., Casadevall, A. Melanization decreases the susceptibility of Cryptococcus neoformans to enzymatic degradation. Mycopathologia 151, 53–56 (2001). https://doi.org/10.1023/A:1010977107089
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DOI: https://doi.org/10.1023/A:1010977107089