Banca de DEFESA: JOSÉ MÁRCIO GOMES FERNANDES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : JOSÉ MÁRCIO GOMES FERNANDES
DATE: 05/10/2021
TIME: 09:00
LOCAL: UFSJ
TITLE:

BIOCHEMICAL EVALUATION OF THE THORAX AND ABDOMEN OF Culex spp LARVES AFTER EXPOSURE TO INSECTICIDES DOSE

KEY WORDS:

 Culicidae, mosquitoes, enzymes, biochemistry   , insecticides, oxidative stress.

PAGES: 67
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:

The Culex genus has great sanitary importance in Brazil, being the transmitter of filariasis and, recently, reported as a possible transmitter of Zika Virus. Widespread throughout the country, the practice of using insecticides is the most commonly employed to control the proliferation of mosquitoes. These insecticides usually cause several damages to the insects, either by altering the activity of some enzymes, such as Acetylcholinesterase (AChE), or in the excessive production of Reactive Oxygen Species (ROS), causing paralysis or even death. For mosquitoes, there are reports that resistance is associated with antioxidant enzymes present in these organisms, such as Superoxide Dismutase (SOD), which protect the animals from damage caused by ROS. Thus, this study aimed to evaluate the effects of insecticides on the oxidative stress pathway and cell membranes in 3rd and 4th instar larvae of Culex spp. To this end, outdoor tanks were set up to obtain the larvae, and then they were exposed to the LC₅₀ of the insecticides. The organophosphate Temephos and the ivermectin derivative Ivomec showed lower LC₅₀, therefore were selected for the analysis of their effects on membrane and oxidative stress of the larvae. The larval groups were exposed to the LC₅₀ of the insecticides for 24 hours and later, material was prepared to perform the evaluation of the Na⁺/K⁺-ATPase pump activity, dosage of GSH, Hydrogen Peroxide, Lipoperoxidation and Carbonylated Protein levels, SOD and AChE enzyme activity. Initially we detected that the amount of total protein decreased after the treatments with the insecticides even though the larvae survived the treatments. Afterwards, we identified in both treatments a significant reduction in SOD activity, followed by a decrease in the amount of Hydrogen Peroxide and GSH. Lipid peroxidation was lower in the treated larvae and carbonylated protein decreased on treatment with Ivomec and increased about 3-fold after treatment with Temephos. Na⁺/K⁺-ATPase and AChE activity were more drastically inhibited after Temephos treatment. The results point to the imbalance caused by the insecticides on the membranes and the function of important proteins such as AChE. Furthermore, the changes in the antioxidant system indicate an attempt to adapt to the changes caused by treatment with the insecticides.

BANKING MEMBERS:
Presidente - 1716846 - VANESSA FARIA CORTES
Externa ao Programa - 1544462 - HERICA DE LIMA SANTOS
Externo à Instituição - LUCIANO ANDRADE MOREIRA - Fiocruz - PE