Banca de DEFESA: GRACIETE SOARES LIBORIO VERÍSSIMO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : GRACIETE SOARES LIBORIO VERÍSSIMO
DATE: 02/06/2023
TIME: 09:00
LOCAL: Instituto de Biologia
TITLE:

Genomic and phenotypic analyzes of the surface polysaccharide poly-N-acetylglucosamine (PNAG) in bacteria of the genus Leptospira.

KEY WORDS:

biofilm; extracellular matrix; expolysaccharide; leptospirosis; pga operon

PAGES: 60
BIG AREA: Ciências Biológicas
AREA: Microbiologia
SUBÁREA: Biologia e Fisiologia dos Microorganismos
SPECIALTY: Bacterologia
SUMMARY:

Poly-β-1,6-N-acetyl-glucosamine (PNAG) is a surface polysaccharide widely expressed and present in the biofilm matrix of different bacterial species. PNAG is a virulence factor, involved in protection against innate host defenses, antibiotic therapy, and environmental stress conditions. Pathogenic leptospires are the etiological agents of leptospirosis, an anthropozoonosis with worldwide distribution that impacts human and animal health. Leptospira forms biofilms in the environment and in the kidneys of the reservoir Rattus norvegicus. However, information about the composition of the exopolymer matrix of Leptospira biofilms, as well as the proteins involved in PNAG expression, are poorly characterized. In this work we evaluated PNAG expression by Leptospira through immunofluorescence (IF), biochemical, and genomic approaches. Through IF, we demonstrated that PNAG is expressed on the cell surface of Leptospira with different degrees of pathogenicity and is present in the exopolymer matrix of the biofilm. Biochemical treatment with sodium metaperiodate cleaved N-acetylglucosamine-β- (1,6) bonds, confirming the presence of PNAG. Through comparative genomic analysis, we identified proteins with similarity to glycosyltransferases and deacetylases related to PNAG expression. In this study, we demonstrated the presence of PNAG in Leptospira in the planktonic phenotype and in the biofilm matrix. Our study expands knowledge about Leptospira biofilm composition and contributes to the understanding of possible Leptospira survival mechanisms in the environment and in the host-pathogen relationship.

COMMITTEE MEMBERS:
Presidente - 1879071 - PAULA CARVALHAL LAGE VON BUETTNER RISTOW
Externa à Instituição - FLÁVIA FIGUEIRA ABURJAILE - UFMG
Externa à Instituição - ANGELA SILVA BARBOSA