|Nachman, Ronald - Ron|
|De Loof, Arnold|
Submitted to: Invertebrate Reproduction and Development
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/22/2002
Publication Date: 6/5/2002
Citation: Torfs, P., Nachman, R.J., Poulos, C., De Loof, A., Schoofs, L. 2002. Activity of crustacean myotropic neuropeptides on the oviduct and hindgut of the crayfish Astacus leptodactylus. Invertebrate Reproduction and Development. 41:137-142. Interpretive Summary: Because of problems with the development of resistance to conventional pesticides, there is a critical need for new concepts and alternative approaches in controlling insect pests. The basic premise of this research is that neuropeptides (short chains of amino acids) serve as potent internal messengers in insects to regulate vital functions. New, selective control measures may be developed by designing metabolically stable mimics of these neuropeptides that actively inhibit or over-stimulate functions regulated by them, resulting in disruption of the internal environment of the insect. We report on the effects of several classes of neuropeptides, shared by both insects and crustaceans, on two internal organs in crayfish associated with aspects of reproduction and digestion. We find that of the 'PK', 'SK', 'ITK', and kinin classes of neuropeptides, only the latter demonstrated effects on the two organs. Furthermore, the structures of the crustacean kinins differ from those of the same class in insects in several key structural regions. A deeper understanding of the structures and functions of neuropeptides from insects and edible crustaceans will aid in the design of neuropeptide mimics capable of distinguishing between pests and beneficial organisms cultivated in aquaculture. The work brings us one step closer to the development of practical neuropeptide-like substances that will be effective in controlling pest insects in an environmentally friendly fashion.
Technical Abstract: In crustaceans, a large number of peptides have been identified because of their effect on visceral muscles. Predominantly the heart and the hindgut have been used to purify myotropic peptides from crustaceans. Lately, a number of myotropins were purified from the central nervous system of crustaceans through their ability to induce Leucophaea maderae hindgut contractions. Pev-tachykinin, Pev, SK-2, Pev-kinins 1-6 and Pev-Pk 1 and 2 were tested on their ability to affect the contractility of the crayfish (Astacus leptodactylus) oviduct and hindgut. We have demonstrated for the first time that the muscular sheath surrounding the crayfish oviduct is a possible target for myotropic neuropeptides. The crustacean myotropins (Pev-kinins 1-6) were able to increase the basal tonus of the crustacean oviduct. The other tested myotropins were inactive in this bioassay. Pev-kinins proved to be potent stimulators of crayfish hingut contractions, this in contrast to Pev-tachykinin and Pev-SK.