Thiago Carrazoni1, Marines de Avila Heberle2, Ana Paula Artusi Perin2, Ana Paula Zanatta2, Polyana Veloso Rodrigues2, Fabiola Duarte Machado Dos Santos2, Carlos Gabriel Moreira de Almeida3, Ricardo Vaz Breda4, Douglas Silva Dos Santos5, Paulo Marcos Pinto3, Jaderson Costa da Costa4, Celia Regina Carlini6, Cháriston André Dal Belo7. 1. Graduate Program in Cell and Molecular Biology, Biotechnology Center, Federal University of Rio Grande do Sul, Porto Alegre, Brazil; Laboratory of Neurobiology and Toxinology, Lanetox, Federal University of Pampa, São Gabriel, RS, Brazil; Laboratory of Neurotoxins, Laneurotox, Brain Institute of Rio Grande do Sul, InsCer, PUCRS, Porto Alegre, RS, Brazil. 2. Laboratory of Neurobiology and Toxinology, Lanetox, Federal University of Pampa, São Gabriel, RS, Brazil. 3. Laboratory of Neurobiology and Toxinology, Lanetox, Federal University of Pampa, São Gabriel, RS, Brazil; Laboratory of Neurotoxins, Laneurotox, Brain Institute of Rio Grande do Sul, InsCer, PUCRS, Porto Alegre, RS, Brazil. 4. Laboratory of Neurotoxins, Laneurotox, Brain Institute of Rio Grande do Sul, InsCer, PUCRS, Porto Alegre, RS, Brazil. 5. Laboratory of Neurobiology and Toxinology, Lanetox, Federal University of Pampa, São Gabriel, RS, Brazil; Laboratory of Neurotoxins, Laneurotox, Brain Institute of Rio Grande do Sul, InsCer, PUCRS, Porto Alegre, RS, Brazil; Graduate Program in Biological Sciences: Biochemical Toxicology, Federal University of Santa Maria, Santa Maria, Brazil. 6. Graduate Program in Cell and Molecular Biology, Biotechnology Center, Federal University of Rio Grande do Sul, Porto Alegre, Brazil; Laboratory of Neurotoxins, Laneurotox, Brain Institute of Rio Grande do Sul, InsCer, PUCRS, Porto Alegre, RS, Brazil. Electronic address: celia.carlini@pucrs.br. 7. Laboratory of Neurobiology and Toxinology, Lanetox, Federal University of Pampa, São Gabriel, RS, Brazil; Laboratory of Neurotoxins, Laneurotox, Brain Institute of Rio Grande do Sul, InsCer, PUCRS, Porto Alegre, RS, Brazil; Graduate Program in Biological Sciences: Biochemical Toxicology, Federal University of Santa Maria, Santa Maria, Brazil. Electronic address: charistonbelo@unipampa.edu.br.
Abstract
BACKGROUND: Ureases of Canavalia ensiformis are natural insecticides with a still elusive entomotoxic mode of action. We have investigated the mechanisms involved in the neurotoxicity induced by Jack Bean Urease (JBU) in Nauphoeta cinerea (Olivier). METHODS: To carry out this study we have employed biochemical and neurophysiological analysis of different cockroach organ systems. RESULTS AND CONCLUSIONS: The injection of the insects with JBU (0.75-6μg/g animal), although not lethal within 24h, caused significant inhibition of the brain acetylcholinesterase activity (60±5%, p<0.05, n=6). JBU (1.5μg/200μL), acetylcholine (0.3μg/200μL) or neostigmine (0.22μg/200μL), induced a positive cardiac chronotropism (∼25%) in the cockroaches (p<0.05, n=9). JBU (6μg/g) increased the insects' grooming activity (137±7%), similarly to octopamine (15μg/g) (p<0.05, n=30, respectively). Pretreating the insects with phentolamine (0.1μg/g) prevented the JBU- or octopamine-induced increase of grooming activity. JBU (6μg/g) caused 65±9% neuromuscular blockade in the cockroaches, an effect prevented by bicuculline (5μg/g) (p<0.05, n=6). JBU (6μg/g) decreased the frequency whilst increasing the amplitude of the spontaneous neural compound action potentials (1425±52.60min-1, controls 1.102±0.032mV, p<0.05, n=6, respectively). Altogether the results indicate that JBU induces behavioral alterations in Nauphoeta cinerea cockroaches probably by interfering with the cholinergic neurotransmission. The neuromuscular blocking activity of JBU suggests an interplay between acetylcholine and GABA signaling. GENERAL SIGNIFICANCE: The search for novel natural molecules with insecticide potential has become a necessity more than an alternative. Understanding the mode of action of candidate molecules is a crucial step towards the development of new bioinsecticides. The present study focused on the neurotoxicity of Canavalia ensiformis urease, a natural insecticide, in cockroaches and revealed interferences on the cholinergic, octopaminergic and GABA-ergic pathways as part of its entomotoxic mode of action.
BACKGROUND: Ureases of Canavalia ensiformis are natural insecticides with a still elusive entomotoxic mode of action. We have investigated the mechanisms involved in the neurotoxicity induced by Jack Bean Urease (JBU) in Nauphoeta cinerea (Olivier). METHODS: To carry out this study we have employed biochemical and neurophysiological analysis of different cockroach organ systems. RESULTS AND CONCLUSIONS: The injection of the insects with JBU (0.75-6μg/g animal), although not lethal within 24h, caused significant inhibition of the brain acetylcholinesterase activity (60±5%, p<0.05, n=6). JBU (1.5μg/200μL), acetylcholine (0.3μg/200μL) or neostigmine (0.22μg/200μL), induced a positive cardiac chronotropism (∼25%) in the cockroaches (p<0.05, n=9). JBU (6μg/g) increased the insects' grooming activity (137±7%), similarly to octopamine (15μg/g) (p<0.05, n=30, respectively). Pretreating the insects with phentolamine (0.1μg/g) prevented the JBU- or octopamine-induced increase of grooming activity. JBU (6μg/g) caused 65±9% neuromuscular blockade in the cockroaches, an effect prevented by bicuculline (5μg/g) (p<0.05, n=6). JBU (6μg/g) decreased the frequency whilst increasing the amplitude of the spontaneous neural compound action potentials (1425±52.60min-1, controls 1.102±0.032mV, p<0.05, n=6, respectively). Altogether the results indicate that JBU induces behavioral alterations in Nauphoeta cinerea cockroaches probably by interfering with the cholinergic neurotransmission. The neuromuscular blocking activity of JBU suggests an interplay between acetylcholine and GABA signaling. GENERAL SIGNIFICANCE: The search for novel natural molecules with insecticide potential has become a necessity more than an alternative. Understanding the mode of action of candidate molecules is a crucial step towards the development of new bioinsecticides. The present study focused on the neurotoxicity of Canavalia ensiformis urease, a natural insecticide, in cockroaches and revealed interferences on the cholinergic, octopaminergic and GABA-ergic pathways as part of its entomotoxic mode of action.
Authors: Pedro Silvino Pereira; Adrielle Rodrigues Costa; Thalyta Julyanne Silva de Oliveira; Carlos Vinícius Barros Oliveira; Maria do Carmo Alves de Lima; Jamerson Ferreira de Oliveira; Bonglee Kim; Henrique D M Coutinho; Antonia Eliene Duarte; Jean Paul Kamdem; Teresinha Gonçalves da Silva Journal: Antioxidants (Basel) Date: 2022-02-18
Authors: Graziela Holken Lorensi; Raquel Soares Oliveira; Allan P Leal; Ana Paula Zanatta; Carlos Gabriel Moreira de Almeida; Yuri Correia Barreto; Maria Eduarda Rosa; Patrícia de Brum Vieira; Carlos José Brito Ramos; Filipe de Carvalho Victoria; Antônio Batista Pereira; Valéria LaneuvilleTeixeira; Cháriston André Dal Belo Journal: Mar Drugs Date: 2019-10-10 Impact factor: 5.118