Banca de DEFESA: Daniel Oliveira da Mata

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : Daniel Oliveira da Mata
DATE: 30/08/2022
TIME: 09:00
LOCAL: Auditório 3 do Instituto de Biologia
TITLE:

Electrophysiological characterization of toxins Tst1 and Ts3 purified from Tityus stigmurus venom

KEY WORDS:

NaScTx; neurotoxin; scorpion venom; Tityus stigmurus; voltage-gates sodium channel; β-scorpion toxin; α-scorpion toxin.

PAGES: 80
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

Belonging to the Arthropoda phylum, scorpions represent approximately 1.5% of arachnid species.  In Brazilian several species of scorpions are found, being present in all territory. Among them, the most important and abundant species are the animals belonging to the genus Tityus, due to their great variety and medical importance. One of the most important ones is Tityus stigmurus, an endemic species from the Northeast region of Brazil. This species stands out for the high number of accidents in the Northeast region of the country, being responsible for the large number accidents, leading to hospitalization and cases of death. The venom of these animals is composed by several different compounds, in which the most prominent are peptides, also known as neurotoxins. These neurotoxins are able to interact and affect the functioning of ion channels such as potassium, calcium and voltage-gated sodium channels (Nav), responsible for the propagation and initiation of nerve signals. In this work, the venom of the scorpion Tityus stigmurus was extracted and fractionationed using Reverse Phase High Performance Liquid Chromatography (RP-HPLC) technique. The fractions collected were analyzed in a Mass Spectrometer (MALDI-TOF) and the fractions of interest were separated and partially sequenced using ISD method. After the purification and identification, the purified toxins, corresponding to toxins Tst1 and Tst3, were tested in voltage-gated sodium channels (Nav 1.1 to 1.7) using the patch-clamp technique in whole cell mode. The toxin Tst1 demonstrated a characteristic activity of β-toxin, altering the opening potential of sodium channels (Nav) and inhibiting current, having a greater action on the Nav 1.3 subtype. The toxin Tst3 showed a characteristic of α-toxins, altering the rapid inactivation of sodium channels, with subtypes Nav 1.3, 1.6 and 1.7 being the most compromised. Tst1 and Tst3 toxins are the first toxins purified from Tityus stigmurus venom widely characterized in different isoforms of sodium channels (Nav).

BANKING MEMBERS:
Externo à Instituição - CARLOS BERNARDO TAUIL
Presidente - 405268 - ELISABETH NOGUEIRA FERRONI
Externo à Instituição - HARRY MORALES DUQUE - UCB
Interna - 1122620 - SONIA MARIA DE FREITAS