Banca de QUALIFICAÇÃO: RAQUEL JEMIMA VIANA LIMA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : RAQUEL JEMIMA VIANA LIMA
DATE: 12/12/2025
TIME: 09:00
LOCAL: sala virtual https://meet.google.com/cfz-xhwf-nxc
TITLE:

MODELING, VIRTUAL SCREENING AND ENZYMATIC DOCKING OF TREHALOSE 6-PHOSPHATE PHOSPHATASE AND EVALUATION OF THE INSECTICIDAL EFFECT OF N-(p-tolylsulfonyl)phthalimide AND THE SOLUBLE RESIN FRACTION OF Bertholletia excelsa ON Aedes aegypti (DIPTERA: CULICIDAE)

KEY WORDS:

Molecular Target, Brazil nut tree, Chemical control, Arboviruses, Vector

PAGES: 96
BIG AREA: Ciências Biológicas
AREA: Parasitologia
SUBÁREA: Entomologia e Malacologia de Parasitos e Vetores
SUMMARY:

Currently, research is being conducted to create new-generation insecticides by utilizing molecules that interact with specific molecular targets, such as enzymes linked to trehalose metabolism and other targets related to essential insect functions. Thus, the objective of this work was to model, perform virtual screening, and molecular docking of the Trehalose 6-Phosphate Phosphatase enzyme from Aedes aegypti (AaeTPP) with Phthalimide derivatives and the soluble resin fraction (SF) of Bertholletia excelsa (Brazil nut tree), and to evaluate the larvicidal effects of one of the Phthalimide derivatives, i.e., N-(p-tolylsulfonyl)phthalimide (PNT), and the soluble resin fraction of B. excelsa against Aedes aegypti.

The three-dimensional structure of the AaeTPP enzyme was modeled by homology. Following structural validation, virtual screening of PubChem compounds was performed based on similarity to the substrate Trehalose-6-Phosphate (T6P) and the inhibitor N-(phenylthio)phthalimide (NPP), as well as to the metabolites present in the soluble resin fraction of B. excelsa. These compounds were then subjected to molecular dynamics simulation, and the analyses indicated stability and highlighted ligands with inhibitory potential.

A stock solution of the PNT molecule was prepared with 145 mg of PNT in 50% dimethyl sulfoxide (DMSO) and 50% deionized water, and concentrations of 100, 50, 25, 10, and 5 ppm were tested. Larvicidal tests were carried out in a 24-well Elisa plate in triplicate with 5 larvae (L1) with a final volume of 1 mL and a control with 0.5% DMSO. A stock solution was prepared with 5 g of B. excelsa resin 400.1 and 208.3 in 95% Methanol and 5% DMSO, and the SF was tested at concentrations of 224, 560, 784, 1120, 1680, and 2240 ppm. Larvicidal tests were performed in 50 mL plastic containers with a final volume of 10 mL, in triplicate with 10 third-instar larvae, and the control with 1% of the solution used to dilute the resin in distilled water. Mortality in the experiments was recorded at intervals of 24–96 hours.

The modeling of the AaeTPP enzyme was based on the structure of TPP from Mycobacterium tuberculosis (PDB: 5GVX), showing 30.8% similarity. The structure had an RMSD of 0.603 A˚ and 80.23% positive validation by Verify3D. 154 Phthalimide derivatives exhibited a better binding energy than the natural substrate T6P (−5.18 kcal/mol), and 50 compounds from the B. excelsa soluble fraction showed favorable energy (−9.75 kcal/mol). In the molecular dynamics simulations (150 ns), the AaeTPP–PNT complex showed greater structural stability than T6P. The analysis indicated that PNT had the most favorable binding energy (−16.68 kcal/mol).

PNT concentrations between 10 and 100 ppm caused 38% to 52% mortality after 24 hours of exposure, reaching 92% at 100 ppm after 72 hours. We observed that, in both B. excelsa samples, concentrations from 224 to 1120 ppm did not cause larval mortality. The Estimated Lethal Concentrations (LC) of PNT required to kill 50% (LC50), although tending to decrease over the observation time, did not significantly differ from each other. The LC90 values, however, were 7 times higher than the LC50 at 24 hours, reaching 11 times higher after 48 hours. The LC50 values for both resin samples decreased over time: for sample 400.1, LC50 was 1741 ppm (48h), 1411 ppm (72h), and 1117 ppm (96h). For sample 208.3, LC50 was 1816 ppm (48h), 1562 ppm (72h), and 1493 ppm (96h).

The increase in concentration and exposure time of Ae. aegypti larvae to N-(p-tolylsulfonyl)phthalimide demonstrated larvicidal potential, whereas the resin fractions of B. excelsa showed low larvicidal potential against Ae. aegypti immatures.

COMMITTEE MEMBERS:
Interno - 1530806 - ALEXANDRE DE ALMEIDA E SILVA
Externo ao Programa - 3269899 - LUCAS MARQUES DA CUNHA - UNIRExterna à Instituição - ROSEMARY APARECIDA ROQUE - INPA