Entomotoxicity of jaburetox: revisiting the neurotoxic mechanisms in insects.

Ureases are metalloenzymes that hydrolyze urea to ammonia and carbamate. The main urease isoforms present in the seeds of (jack bean urease - JBU and canatoxin) exert a variety of biological activities. The insecticidal activity of JBU is mediated, at least in part, by jaburetox (Jbtx), a recombinant peptide derived from the JBU amino acid sequence. In this article, we review the neurotoxicity of Jbtx in insects. The insecticidal activity of Jbtx has been investigated in a variety of insect orders and species, including Blattodea (the cockroaches , , e ), Bruchidae ( - cowpea weevil), Diptera ( - mosquito), Hemiptera ( - cotton stainer bug; - large milkweed bug, and the kissing bugs and ), Lepidoptera ( - fall army worm) and Orthoptera ( - locust). In , the injection of Jbtx induces marked alteration of locomotor and grooming behavior, whereas in Jbtx causes leg paralysis, an extension of the proboscis and abnormal antennal movements. Electromyographical analysis showed that Jbtx causes complete neuromuscular blockade in . The same treatment in and causes a decrease in the action potential firing rate. Jbtx forms membrane pore-channels compatible with cations in bilipid membranes. A study using voltage-gated sodium (Nav1.1) channels that were heterologously expressed in oocytes correlated the entomotoxicity of Jbtx with the activation of these channels. Taken together, these findings demonstrate the potential of this peptide as a natural pesticide.