Neurotoxic effects of sublethal concentrations of cyanobacterial extract containing anatoxin-a(s) on Nauphoeta cinerea cockroaches

Author(s):Show less -

dos Santos, Douglas Silva ^{[1, 2, 3]} ; Rosa, Maria Eduarda ^[1] ; Zanatta, Ana Paula ^[1] ; Oliveir, Raquel Soares ^[1] ; Moreira de Almeida, Carlos Gabriel ^{[1, 3]} ; Leal, Allan Pinto ^[1] ; Sanz, Miriam ^[4] ; Fernandes, Kelly Afonsina ^[4] ; de Souza, Velci Queiroz ^[1] ; de Assis, Denis Reis ^[5] ; Pinto, Ernani ^[4] ; Dal Belo, Chariston Andre ^{[1, 2, 3]}

Affiliation

^[1] Univ Fed Pampa UNIPAMPA, LANETOX, Ave Antonio Trilha 1847, BR-97300000 Sao Gabriel, RS - Brazil

^[2] Univ Fed Santa Maria, Programa Posgrad Ciencias Biol Bioquim Toxicol PP, Ave Roraima 1000, BR-97105900 Santa Maria, RS - Brazil

^[3] Pontificia Univ Catolica Rio Grande do Sul PUCRS, Inst Cerebro INSCER, Ave Ipiranga 6690, Porto Alegre, RS - Brazil

^[4] Univ Sao Paulo, Fac Ciencias Farmaceut, Sao Paulo - Brazil

^[5] Univ Tours, Fac Med, INSERM, U1253 Imaging & Brain, Team Neurogen & Neuronal Physiopathol, 10 Bd Tonnelle, F-37032 Tours - France

• Document type: Journal article
• Source: ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY; v. 171, p. 138-145, APR 30 2019.
• Web of Science Citations: 2

Abstract

The detection of cyanotoxins, such as the anatoxin-a(s), is essential to ensure the biological safety of water environments. Here, we propose the use of Nauphoeta cinerea cockroaches as an alternative biological model for the biomonitoring of the activity of anatoxin-a(s) in aquatic systems. In order to validate our proposed model, we compared the effects of a cyanobacterial extract containing anatoxin-a(s) (CECA) with those of the organophosphate trichlorfon (Tn) on biochemical and physiological parameters of the nervous system of Nauphoeta cinerea cockroaches. In brain homogenates from cockroaches, CECA (5 and 50 mu g/g) inhibited acetylcholinesterase (AChE) activity by 53 +/- 2% and 51 +/- 7%, respectively, while Tn (5 and 50 mu g/g) inhibited AChE activity by 35 +/- 4% and 80 +/- 9%, respectively (p < 0.05; n = 6). Moreover, CECA at concentrations of 5, 25, and 50 mu g/g decreased the locomotor activity of the cockroaches, diminishing the distance travelled and increasing the frequency and duration of immobile episodes similarly to Tn (0.3 mu g/g) (p < 0.05, n = 40, respectively). CECA (5, 25 and 50 mu g/g) induced an increase in the leg grooming behavior, but not in the movement of antennae, similarly to the effect of Tn (0.3 mu g/g). In addition, both CECA (50 mu g/200 mu l) and Tn (0.3 mu g/200 mu l) induced a negative chronotropism in the insect heart (37 +/- 1 and 47 +/- 8 beats/min in 30 min, respectively) (n = 9, p > 0.05). Finally, CECA (50 mu g/g), Tn (0.3 mu g/g) and neostigmine (50 mu g/g) caused significant neuromuscular failure, as indicated by the monitoring of the in vivo neuromuscular function of the cockroaches, during 100 min (n = 6, p < 0.05, respectively). In conclusion, sublethal doses of CECA provoked entomotoxicity. The Tn-like effects of CECA on Nauphoeta cinerea cockroaches encompass both the central and peripheral nervous systems in our insect model. The inhibitory activity of CECA on AChE boosts a cascade of signaling events involving octopaminergic/dopaminergic neurotransmission. Therefore, this study indicates that this insect model could potentially be used as a powerful, practical, and inexpensive tool to understand the impacts of eutrophication and for orientating decontamination processes. (AU)

• FAPESP's process: 14/50420-9 - Secondary metabolites from aquatic microrganisms and their impact on seafood and freshwater fish aquaculture
• Grantee: Ernani Pinto Junior
• Support Opportunities: Regular Research Grants