NEUROTOXICITY OF JABURETOX, A UREASE-DERIVED PEPTIDE: EFFECTS ON ENZYMES ACTIVITIES IN TISSUES OF TWO INSECT SPECIES

NORONHA, M.S; GRAHL, M.V.C; MOYETTA, N.R.; PERIN, A.P.A; CARLINI, C.R.; BROLL, V.; FRUTTERO, L.L

Águas de Lindóia, São Paulo

Encuentro; 46a Reunião Anual da Sociedade Brasileira de Bioquímica e Biologia Molecular; 2017

Sociedade Brasileira de Bioquímica e Biologia Molecular

Introduction: Jaburetox is a recombinant peptide (11 kDa) derived from Canavalia ensiformis (Jack Bean) urease. The peptide induces toxic effects on insects of different orders. When injected, Jaburetox is lethal for the triatomine Rhodnius prolixus but not to the cockroach Nauphoeta cinerea, despite the neuromuscular junction blockade seen in vivo. Jaburetox was shown to interfere on muscle contractility, to affect the immune system and to inhibit diuresis. Our previous data suggested the central nervous system (CNS) is a target of Jaburetox in insects. Objectives: In order to improve the understanding of mechanism of action of Jaburetox, we employed a susceptible (R. prolixus) and non-susceptible (N. cinerea) insect model to explore the effects of this peptide, focusing on enzymatic pathways of the insect?s CNS. Material and Methods: Spectrophotometric assays were employed to characterize the in vitro effect of Jaburetox upon R. prolixus and N. cinerea CNS tissue homogenates. Results and Discussion: The treatment of the insect?s CNS homogenates partially inhibited the activity of nitric oxide synthase (NOS) of both species, indicating an effect of the peptide on the nitrinergic signaling. Interestingly, Jaburetox incubation with homogenates increased the activity of UDP-N-acetylglucosamine pyrophosphorylase (UAP, involved in chitin synthesis and glycosylation pathways) in R. prolixus but it caused no effects on N. cinerea?s UAP. In addition, no changes were observed on the activity of acid phosphatase enzyme(s), a possible link between UAP and NOS, when CNS homogenates of either insect were incubated with Jaburetox. Conclusions: Taken together, our findings indicate that Jaburetox affects the nitrinergic signaling in both insects models. The fact that Jaburetox had no effect on UAP enzyme activity may explain why N. cinerea is not susceptible to the lethal effect of the peptide. More experiments are necessary to better understand the effects of Jaburetox on the CNS of different insects.