Banca de QUALIFICAÇÃO: EDEN SILVA E SOUZA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : EDEN SILVA E SOUZA
DATE: 31/01/2020
TIME: 14:00
LOCAL: BioME
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.

PAGES: 35
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

Cryptococcosis is a fungal infection caused by Cryptococcus gattii or C. neoformans species. The infection starts when dried cells or spores are inhaled and reach the lungs. If not properly treated, infection may reach the central nervous system and result in death. Cryptococcosis treatment takes a 3-stage regimen and uses three drugs: fluconazole, amphotericin B, and flucytosine. Although effective, these drugs can result in fungal resistance and can be toxic for patients. We propose to investigate the mode of action of the antifungal compound plumieridine and its molecular target in C. neoformans. To verify that, a series of in vitro and in silico experiments were performed. Through a virtual screening approach, chitinase was identified as the fungal target. Molecular models for each chitinase were created and molecular docking indicates that the four chitinases in C. neoformans have its activity inhibited by the iridoid. For in vitro assays, plumieridine was obtained from Allamanda polyantha seed extract and its presence confirmed through hydrogen and carbon NMR. Susceptibility assay, determined over MIC, was 0.250 mg/mL. Inhibition of chitinolytic activity assay shows activity is reduced in secreted chitinase activity, however chitinolytic activity is not inhibited in the insoluble cell-related fraction. RT-qPCR revels only CHI22 expression levels are reduced by plumieridine treatment. Also, this is the only chitinase affected by the carbon source tested. Confocal microscopy reveled changes in the distribution pattern of chitooligomers in the cell wall from a polarized to a diffuse pattern. Results confirm virtual screening target prediction and show that inhibition of C. neoformans chitinases by plumieridine leads to incomplete cytokinesis.

BANKING MEMBERS:
Interno - 1893445 - EUZEBIO GUIMARAES BARBOSA
Presidente - 1513597 - JOAO PAULO MATOS SANTOS LIMA