CIBICI   14215
CENTRO DE INVESTIGACION EN BIOQUIMICA CLINICA E INMUNOLOGIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
JABURETOX, A UREASE-DERIVED PEPTIDE: EFFECTS ON ENZYMATIC PATHWAYS OF A COCKROACH
Autor/es:
FRUTTERO, L.L; NORONHA, M.S; STANISÇUASKI FERNANDA; MOYETTA, N.R.; CARLINI CELIA REGINA; PERIN APA
Lugar:
Porto Alegre
Reunión:
Congreso; Toxi-latin. Modern toxicology for health and prevention.; 2018
Resumen:
INTRODUCTION: Jaburetox (Jbtx) is a recombinant peptide (~11 kDa) derived from one of the Canavalia ensiformis (Jack Bean) urease isoforms. The peptide induces several toxic effects on insects of different orders, including the interference on muscle contractility in the cockroach Nauphoeta cinerea as well as the activation of the immune system in the Chagas? disease vector Rhodnius prolixus. When injected, the peptide is lethal for nymphs of R. prolixus. Previous data demonstrated that the central nervous system (CNS) of Triatoma infestans and R. prolixus, is a target organ for Jbtx. In addition, Jbtx modulates the enzyme activities of the UDP-N-acetylglucosamine pyrophosphorylase (UAP, involved in chitin synthesis and glycosylation pathways) and nitric oxide synthase (NOS, nitrinergic signaling and immunity response) in the CNS of those species. OBJECTIVES: To explore the effects induced by Jbtx on the CNS, focusing on the enzymatic activities of UAP, NOS, acid phosphatases (APs), and acetylcholinesterase (AChE). In addition, we evaluated the insecticidal effect of Jbtx upon N. cinerea nymphs. MATERIAL AND METHODS: The enzymatic experiments were performed with adult cockroaches. The in vitro treatment with Jbtx was carried out pre-incubating the CNS homogenates with different concentrations of the peptide or the same volume of buffer for the controls. The in vivo treatment was performed by abdominal injection of different doses of Jbtx or the same volume of buffer for the controls, followed by dissection of the CNS 6 hours afterwards. Spectrophotometric assays were employed to measure the enzyme activities. The insecticidal assay against N. cinerea nymphs was performed by abdominal injections of 50 μg of Jbtx per g of insect and the survival rate was followed for 10 days. Statistical Analysis employed were the Student ?t? and ANOVA, followed by Dunnett as post hoc test. The experiments were performed at least four times. P value < 0.05 were considered statistically significantly. RESULTS AND DISCUSSION: In N. cinerea, both in vivo and in vitro treatments with Jbtx partially inhibited the activity of NOS (decrease of 83.32% and 78.15% respectively) and a similar inhibition profile was previously observed in R. prolixus. Interestingly, Jbtx has no effect upon N. cinerea?s UAP activity, contrasting with R. prolixus? findings, in which the activity was increased. Also in contrast with the profile observed in R. prolixus, the in vivo Jbtx treatment increased the activity of APs (16.58%) in the cockroach. Finally, Jbtx injections decreased the AChE activity (59.62%) in adult cockroaches and had no insecticidal effect on nymphs. CONCLUSIONS: Our findings indicate that Jbtx affects the NOS, AChE and APs activities. The fact that Jbtx affects differently the enzyme activities in R. prolixus and N. cinerea, may explain why the cockroach is not susceptible to the lethal effect of the peptide. FINANCIAL SUPPORT: CNPq and CAPES.