Banca de QUALIFICAÇÃO: RAFAEL BARBOSA DE MOURA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : RAFAEL BARBOSA DE MOURA
DATA : 19/12/2019
HORA: 09:00
LOCAL: Centro de Ciências Agrárias e da Biodiversidade (CCAB)
TÍTULO:

EVALUATION OF ANTIBACTERIAL AND MODULATORY ACTIVITY OF
Canavalia ensiformis (ConA) and Canavalia brasiliensis (ConBr) LECTINES AGAINST STANDARD AND MULTI-RESISTANT STRAINS

PALAVRAS-CHAVES:

 Lectins. Efflux pump. Bacterial resistance. Antimicrobials.

PÁGINAS: 48
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

Lectins are proteins capable of binding reversibly and specifically carbohydrates,
which have the ability to agglutinate red blood cells and are found in various
organisms such as plants, organisms eukaryotes and prokaryotes. Plant lectins are a
group of proteins of great biological potential and represent the class of lectins which
present more studies in the literature. Nowadays there is a need for researchers to
discover new drugs that can act directly or indirectly on bacteria, as clinically
antimicrobial resistance mechanisms are increasing on an unprecedented scale. The
need to find molecules that can help reverse these resistance mechanisms is of
utmost need today. In this context, this work aims to isolate the lectins present in
seeds of Canavalia ensiformis (ConA) and Canavalia brasiliensis (ConBr), as well as
to verify their antimicrobial potential against standard, multidrug resistant bacteria
and efflux pump carriers. For this purpose the seeds were ground and the extract
made in 0.15M Nacl, for subsequent extraction in Sephadex-G50 column, where the
solid phase is made of glucose, the proteins were eluted using 0.1M glycine, pH 2.6
and samples read on spectrophotometer at 280 nm. Subsequently the samples were
dialyzed and lyophilized for microbiological tests. The Minimum Inhibitory
Concentration (MIC) was determined using Staphylococcus aureus and Escherichia
coli strains, the strains were kept in specific medium to prove their subtype. MIC was
performed in sterile 96-well microplates and serially diluted 1:1. Modulatory activity
was evaluated using the antibiotics gentamicin, ciprofloxacin and ampicillin. For the
efflux pump test were used two strains of S. aureus containing NorA and MepA
respectively. The study showed that ConA and ConBr lectins have a MIC for all
bacteria tested above or equal to 1024µg / mL, showing no clinically significant
findings for this test; however, in modulation activities ConA was able to modulate the
activity of gentamicin in strains of wild S. aureus (1199) and ConBr showed
significant modulatory activity for modulation in S. aureus (1199) in the presence of
ciprofloxacin. Concavalin A (ConA) shows significant activity for NorA efflux pump
bacteria in the presence of norfloxacin. Similar activities were not clinically significant
for ConBr. Thus, it can be concluded that ConA was able to modulate gentamicin
activity in gram-positive strains, suggesting that the structure of this bacterium, due to
the large amount of carbohydrates on its surface, may provide a mechanism of action
that can be aided. In the presence of lectins, the same can be observed in the results
with efflux pumps (NorA) in which lectin was able to assist the antimicrobial drug by
the presence of this resistance mechanism.

MEMBROS DA BANCA:
Presidente - 1123441 - KAMILA CAMARA CORREIA
Interno - 1305746 - THIAGO MIELLE BRITO FERREIRA OLIVEIRA