Banca de DEFESA: ELLYNES AMANCIO CORREIA NUNES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : ELLYNES AMANCIO CORREIA NUNES
DATE: 30/07/2024
TIME: 09:00
LOCAL: Videoconferência
TITLE:

 

PURIFICATION AND PARTIAL MOLECULAR CHARACTERIZATION OF A MANGANESE-DEPENDENT LECTIN FROM THE SNAKE VENOM Bothrops moojeni

KEY WORDS:

 

Biological activity. Snake venoms. Bioprospecting.

PAGES: 89
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:

Bioactive molecules isolated from venomous animals constitute a variety of compounds with diverse known biological activities that can be directed to the treatment of different diseases. Snake venoms are important representatives of sources of bioactive molecules and are made up of around 90% of proteins and peptides, which may or may not have enzymatic action. These toxins perform different biochemical mechanisms and are therefore responsible for the characterization of accidents caused by snakes. In Brazil, the main causes of snakebites are snakes of the genus Bothrops, family Viperidae, whose envenoming is characterized by proteolytic, hemorrhagic and coagulant activities. Knowledge about the proteins involved in the clinical picture allows the study of heterologous activities related to these toxins. In this context, the objective was to isolate, characterize and understand the biological activities of a protein with lectin activity from the venom of the Bothrops moojeni snake. Therefore, a previous literature review was carried out covering the lectins isolated and characterized from snake venoms and their main characteristics and classification. Added to this, the search for a protein with lectin activity was carried out using Molecular Exclusion Chromatography (CEM) and Reverse Phase High Performance Liquid Chromatography (HPLC-FR), followed by polyacrylamide gel (SDS-PAGE) and hemagglutination assays, inhibition of hemagglutinating activity, dependence on ions, pH and temperature, as well as hemolytic activity and antimicrobial activity against bacterial strains of Acinetobacter baumannii and Staphylococcus aureus, and antibiofilm activity. Molecular exclusion generated a chromatographic profile with 6 peaks that were applied to polyacrylamide gels and the hemagglutination assay. Hemagglutinating activity was observed in fractions 5 and 6, with the best result observed in fraction 5, which was named BmoojL. It was also observed that BmoojL was manganese dependent, unlike most lectins isolated from snakes which are calcium dependent. Furthermore, BmoojL was inhibited in the presence of the carbohydrate’s glucose, fructose, mannose, fucose and N-acetylgalactosamine, and was active at temperatures of up to 80 ºC, and in pH ranges from 5 to 9. The hemolytic assay showed that the molecule does not promote hemagglutination at the concentrations tested (0.5 to 0.0625 mg. mL^-1), showing that the molecule could be applied to some biological tests. Therefore, antimicrobial assays showed that despite not reaching MIC, BmoojL reduced Gram-negative bacterial growth. The antibiofilm assay showed that for S. aureus, BmoojL was effective, considerably reducing biofilm growth at all concentrations tested by around 50%. We also showed that the ion alone and associated with another protein did not perform significant activity, as observed with BmoojL. In this way, we managed to isolate a molecule with lectin activity, although more tests are necessary for its full characterization, we have already highlighted its potential to perform antimicrobial and antibiofilm activity, thus contributing to research involving bioactive molecules isolated from venomous snakes.

COMMITTEE MEMBERS:
Interna - 2578619 - ANA HELONEIDA DE ARAUJO MORAIS
Externa à Instituição - JULIANA PAVAN ZULIANI - UNIR
Presidente - ***.121.724-** - LUDOVICO MIGLIOLO - UCDB
Interno - 1544647 - MATHEUS DE FREITAS FERNANDES PEDROSA
Externo à Instituição - OCTÁVIO LUIZ FRANCO - UCDB