Banca de DEFESA: LORENA SALES FERREIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LORENA SALES FERREIRA
DATE: 12/02/2021
TIME: 08:30
LOCAL: https://meet.google.com/yht-bvqf-wqv
TITLE:

Histological and biochemical changes in Culex quinquefasciatus larvae after exposure to potential pesticides

KEY WORDS:

Culex quinquefasciatus, insecticides, biochemistry, histological analysis

PAGES: 64
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:

The Culex quinquefasciatus mosquito is prevalent in urban areas in many tropical countries and is responsible for the transmission of several diseases. In this way, different substances are used as the main way to combat this insect vector, however, mosquitoes have shown resistance to the pesticides currently used. In this context, the present work aimed to evaluate the action of six classes of xenobiotics: Revolution (selamectin), Bravecto (fluralaner), Tiger® 100 EC (pyriproxifem), Actara® 250 WG (thiametoxam), Vectobac® WG (Bacillus thurigiensis var israelenses- Bti) and Original Neem® (azadiractin) on 3rd instar larvae of C. quinquefasciatus. The pesticides were obtained commercially and the active ingredient of Bravecto, extracted and characterized by melting point techniques and spectroscopy in the infrared region. The LC50 was determined and the histological and biochemical evaluation was performed after the larval exposure the LC50 for 24 hours. The pesticides had the following lethal doses: 1,07x10-2 mgL1 (selamectin); 1,90x10-5 mgL-1 (fluralaner); 2,2x10-3 mgL-1 (pyriproxifem); 3x10-2 mgL-1 (thiametoxam); 9x10-2 mgL-1 (Bti) e 4x10-2 mgL-1 (azadiractin) mgL-1 , making the fluralaner the most potent insecticide. From the biochemical analysis, there was an increase compared to the control of the parameters analyzed in the larvae, namely, the concentration of total proteins and oxidative stress through the reduced glutathione and hydrogen peroxide content, when exposed to all pesticides, except fluralaner, which had the opposite effect (decrease in the level of the biochemical parameters analyzed). In relation to acetylcholinesterase, the enzymatic activity decreased when compared to the control for the pesticide Revolution, but increased when the larvae were treated with the other compounds. In turn, histological analysis showed cell damage in the midgut, changes in the striated border and instability of the peritrophic membrane. In this context, the results obtained showed information that helped to better understand the effects of xenobiotics on larvae, and presented new compounds with potential larvicidal activity against mosquitoes.

BANKING MEMBERS:
Externa ao Programa - 1544462 - HERICA DE LIMA SANTOS
Externo ao Programa - 1526269 - LEANDRO AUGUSTO DE OLIVEIRA BARBOSA
Externo à Instituição - MAGNO AUGUSTO ZAZA BORGES - UNIMONTES
Externo ao Programa - 2875448 - RALPH GRUPPI THOME
Externa à Instituição - SUZAN KELLY VILELA BERTOLUCCI - UFLA