Banca de DEFESA: EDEN SILVA E SOUZA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : EDEN SILVA E SOUZA
DATE: 28/02/2020
TIME: 14:00
LOCAL: BioME - PPg-Bioinfo
TITLE:

Evaluation of the predicted target of plumieridine in Cryptococcus neoformans var. Grubbii H99

KEY WORDS:

Cryptococcus neoformans; plumieridine; antifungal; bioinformatics; virtual screening; drug target, chitinase.

PAGES: 33
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

Cryptococcosis is a fungal infection caused by yeasts of Cryptococcus spp. The infection starts when desiccated cells or spores are inhaled and reach the lungs. If the disease is not properly treated, the infection can evolve and reach the central nervous system and result in meningococcal meningitis and even death. The treatment of cryptococcosis is carried out in three stages and uses three drugs: fluconazole, amphotericin B and 5-flucytosine. Although effective, the use of these drugs can result in fungal resistance and can be toxicity for patients. This work aims to investigate the mode of action of the antifungal compound plumieridine as well as the identification of its molecular target in C. neoformans. For this, a series of in vitro and in silico experiments were carried out. Initially, a chromatographic fraction containing plumieridine was obtained from the aqueous extract from seeds of Allamanda polyantha and the presence of the compound observed through carbon and hydrogen nuclear magnetic resonance. Antifungal activity, assessed through MIC, was 0.250 mg/mL. Through virtual screening based on ligand’s similarity, chitinase was identified as plumieridine’s molecular target. Three- dimensional models of C. neoformans chitinases were created and, through molecular docking, it is observed plumieridine interacts with residues in the active site. Chitinolytic inhibitory activity assays show that activity is significantly reduced in the secreted fraction and soluble cell fraction, however, the chitinolytic activity is little reduced by the presence of plumieridine in the insoluble cell fraction, where higher concentrations of the compound are needed. Although plumieridine is able to inhibit chitinolytic activity, the compound does not appear to affect the transcriptional levels of C. neoformans chitinases: only transcription of CHI22 was reduced in the presence of plumieridine. The treatment with plumieridine still alters the distribution pattern of the chitooligomers in the cellular wall: from a polarized pattern to a diffuse pattern through the wall. The results confirm the prediction of virtual screening and show that inhibition of chitinolytic activity by plumieridine results in incomplete cell division and, consequently, cell death.

BANKING MEMBERS:
Presidente - 745.551.897-87 - MARILENE HENNING VAINSTEIN - UniNewcastle
Interno - 1893445 - EUZEBIO GUIMARAES BARBOSA
Interno - 1267860 - GUSTAVO ANTONIO DE SOUZA
Externo à Instituição - CHARLEY CHRISTIAN STAATS - UFRGS