| Congresso Brasileiro de Microbiologia 2023 | Resumo: 245-2 | ||||
Resumo:Melanin is a naturally occurring pigment found across a diverse spectrum of organisms. Its complex molecular structure renders it highly versatile in various domains. In microorganisms, melanin is also associated with virulence. As a result, a comprehensive exploration of its production and regulation during infections can help to develop strategies that benefit the host. Unraveling how fungal melanin is produced and regulated during infection of the environmental host Acanthamoeba castellanii may be the first step in advancing studies. We employed the model of Fonsecaea pedrosoi, one of the most important agents of chromoblastomycosis and an efficient producer of melanin. We hypothesize that the amoeba, being a natural predator of soil microorganisms, including melanin-producing fungi, may induce this virulence factor in response to the stresses exerted during the interaction. In addition, the amoeba has an enzymatic arsenal that can degrade a large amount of fungal biomolecules, including melanin, through peroxidases. Possible mechanisms of melanin degradation by A. castellanii are being studied and holds paramount significance for the development of innovative technologies. These findings have the potential to pave the way for antifungal agents and commercial applications that harness melanin. Tests were carried out with different types of fungal melanin (DHN, DOPA, and Pyomelanin) to observe the behavior and intensity of binding with A. castellanii and its fractions, in addition to analyzing the generation time of F. pedrosoi after contact with the amoeba. Different fungus to amoeba ratios (1:1, 2:1, 5:1, 10:1) were tested over a 4 hour period to investigate the kinetics of interaction, which rates increased over time and multiplicity of infection. The optimal interaction time was observed at 3 hours with a 2:1 ratio, where over 97% of amoebas were infected. In the investigation of fungus growth rate upon interaction, colony forming unities showed significant increase after 6 hours, reaching up to 76.8% growth compared to the control in medium alone, at 12 hours. Also the influence of amoebas on melanin was preliminarily confirmed through the evaluation of its decay upon contact with amoeba, changes in immunoreactivity and densitometric properties. The inhibitor tricyclazole, will also be used to slow down the production of one of the types of melanin, to characterize the importance of this structure during infection. Future experiments are planned to obtain more concrete insights into the amoeba’s influence on melanin by the F. pedrosoi fungus. These findings are relevant to understanding microbial interactions and help the development of therapeutic approaches in treating fungal infections associated with Fonsecaea pedrosoi. Palavras-chave: Melanin, Degradation, Acanthamoeba castellanii, Fonsecaea pedrosoi, Virulence Agência de fomento:CAPES, CNPQ e FAPERJ | |||||