Amphotericin B mediates killing in Cryptococcus neoformans through the induction of a strong oxidative burst
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2011Author
Sangalli-Leite, Fernanda
Scorzoni, Liliana
Mesa-Arango, Ana Cecilia
Mendes Gianinni, Maria José Soares
Rodríguez-Tudela, Juan Luis
Cuenca-Estrella, Manuel
Zaragoza, Oscar
Suggested citation
Sangalli-Leite, Fernanda;
Scorzoni, Liliana;
Mesa-Arango, Ana Cecilia;
Casas Herranz, Celia;
Herrero Perpiñán, Enrique;
Mendes Gianinni, Maria José Soares;
...
Zaragoza, Oscar.
(2011)
.
Amphotericin B mediates killing in Cryptococcus neoformans through the induction of a strong oxidative burst.
Microbes and Infection, 2011, vol. 13, núm. 5 , p. 457-467.
https://doi.org/10.1016/j.micinf.2011.01.015.
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We studied the effects of Amphotericin B (AmB) on Cryptococcus neoformans using different viability methods (CFUs enumeration, XTT
assay and propidium iodide permeability). After 1 h of incubation, there were no viable colonies when the cells were exposed to AmB concentrations ≥ 1 mg/L. In the same conditions, the cells did not become permeable to propidium iodide, a phenomenon that was not observed
until 3 h of incubation. When viability was measured in parallel using XTT assay, a result consistent with the CFUs was obtained, although we
also observed a paradoxical effect in which at high AmB concentrations, a higher XTT reduction was measured than at intermediate AmB
concentrations. This paradoxical effect was not observed after 3 h of incubation with AmB, and lack of XTT reduction was observed at AmB
concentrations higher than 1 mg/L. When stained with dihydrofluorescein, AmB induced a strong intracellular oxidative burst. Consistent with
oxidative damage, AmB induced protein carbonylation. Our results indicate that in C. neoformans, Amphotericin B causes intracellular damage mediated through the production of free radicals before damage on the cell membrane, measured by propidium iodide uptake.