Banca de QUALIFICAÇÃO: ANTONIO CARLOS VITAL JÚNIOR

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : ANTONIO CARLOS VITAL JÚNIOR
DATE: 02/12/2019
TIME: 08:30
LOCAL: Sala de reuniões do Centro de Biociências.
TITLE:

IN VITRO INVESTIGATION OF THE ANTIFUNGAL AND ANTIBIOFILM ACTIVITY OF THE Agelas dispar EXTRACT Fraction Ag2  on Candida SPECIES.

KEY WORDS:

Candidiasis. Yeasts. Natural products. Alkaloids. Scanning Electron Microscopy.

PAGES: 112
BIG AREA: Ciências Biológicas
AREA: Microbiologia
SUBÁREA: Microbiologia Aplicada
SPECIALTY: Microbiologia Médica
SUMMARY:

Microbial biofilms play a relevant role in human diseases, as they constitute a structural barrier that hinders antimicrobial therapy. For Candida yeasts, biofilms are characterized as a complex three-dimensional arrangement consisting of different cell forms incorporated into an extracellular polymeric substance matrix. In recent decades, the search for natural compounds for the treatment of microbial infections has become increasing with the intention of new alternatives to the mechanisms of resistance to antimicrobials, including those induced by biofilms. The marine sponge, Agelas dispar (Family Agelasidae) has been mentioned as a bioactive source, considering its secondary metabolites, alkaloid derivatives, which present significant pharmacological activity. In this context, marine, different Agelas (Family Agelasidae) has been mentioned as a bioactive source, considering its secondary metabolites, alkaloid derivatives, which present significant pharmacological activity. In this context, the aim of this study was to determine the antifungal and antibiofilm activity of the Ag2 fraction of A. dispar methanolic extract on Candida yeast strains. The biological activity was tested in 13 strains of Candida species, evaluating the Minimum Inhibitory Concentration (MIC) by the broth microdilution technique and the substance profile by the Minimum Fungicidal Concentration (MFC) method. The quantification of the formation and antibiofilm activity of the extract fraction was performed by applying the violet crystal and the biomass produced was evaluated by obtaining the optical densities. The Ag2 fraction of the extract showed antifungal activity for 13 strains, showing MIC_90% = 0.625 mg/mL (38%), followed by 2.5 mg/mL (7.7%), 1.25 mg/mL (23.1 %), 0.3125 mg/mL (15.4%), 0.1562 mg/mL (15.4%). The compound analyzed showed MFC_90% of 5.0 mg/mL (23.1%), 2.5 mg/mL (30.7%), 1.25 mg/mL (23.1%), 0.625 mg / mL (7.7%), 0.3125 mg/mL (15.4%) against Candida spp. Results of biofilm formation indicated that all strains were biofilm producers. Of which 10 (77%) weak producing strains and 3 (23%) moderate producing strains. Thus, the moderate producers: C. krusei, C. glabrata and C. parapsilosis were used in the antibiofilm activity test (in formation and mature), resulting in cell viability inhibition (IC50%) ranging from 49.6% to 57.6%, 70.5% to 76.3% (biofilm in formation) and 42.8% to 67.2%, 63.3% to 78.8% (consolidated biofilm) when these strains were posttreated, respectively, with concentrations of 1.25 mg/mL and 2.5mg/mL. Scanning Electron Microscopy (SEM) confirmed the antibiofilm activity, noting that the concentrations employed were able to cause a quantitative decrease of the microbial community, as well as a structural alteration and cellular destruction in the biofilms in formation and mature. It was concluded that the Ag2 fraction of A. dispar methanolic extract showed good antifungal activity and fungicidal nature, as well as efficient to decrease the microbial load and to modify the structural morphology of the yeasts involved in the biofilm, as observed in SEM. These findings suggest that the mechanism of action of the fraction is at the plasma membrane and/or cell wall level, leading to the belief that Ag2 may be a promising antifungal and antibiofilm therapy strategy against Candida species.

BANKING MEMBERS:
Interna - 1452833 - MARIA CELESTE NUNES DE MELO
Interna - 2121234 - VANIA SOUSA ANDRADE
Externa ao Programa - 1453487 - KATIA CASTANHO SCORTECCI