|Lopez, Juan De Dios|
|Nachman, Ronald - Ron|
Submitted to: Peptides
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/14/2007
Publication Date: 2/15/2008
Citation: Predel, R., Russell, W.K., Russell, D.H., Lopez, J., Esquivel, J.F., Nachman, R.J. 2008. Comparative peptidomics of four related hemipteran species: Pyrokinins, myosuppressin, corazonin, adipokinetic hormone, sNPF, and periviscerokinins. Peptides. 29:162-167. 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 messengers in insects to regulate vital functions. Nevertheless, neuropeptides in and of themselves hold little promise as pest control agents because of susceptibility to being degraded in the target pest. Neuropeptide mimics must be designed that resist degradation by enzymes in the digestive tract and blood of pest insects and interact with the active site within agricultural pests by over-activating or blocking critical, neuropeptide-regulated life functions. The first step is to identify neuropeptide structures in specific insect pests and map sites of production and storage within the nervous system. We report on the identification of neuropeptides of a number of classes from the central nervous system of four species of stink bugs. In addition, storage and release sites have been mapped in the nervous systems of these insect pests. Specifically, we have used state-of-the-art analytical techniques to determine the structures of over fifty peptides from the four species of stink bug. Two of the peptides are associated with regulation of water balance in other insects and two others are associated with either pheromone production or regulation of a hibernation-like state that enhances winter survival in moths. This work represents an important milestone and lead in the development of practical neuropeptide-like substances that will effectively control insect pests in an environmentally friendly fashion.
Technical Abstract: We performed the first comprehensive peptidomic analysis of neurohormones from hemipteran insects by analyzing the neuropeptides of two major neurohemal organs, namely the corpora cardiaca and abdominal perisympathetic organs. For the experiments we selected four related species of polyphagous stinkbugs (Pentatomidae), three of which are known to attack several important food crops. Peptide sequences were identified by MALDI-TOF mass spectrometry; tandem fragmentation of myosuppressin, sNPF, CAPA-periviscerokinins and pyrokinins revealed novel sequences not known from other insects so far. Most Leu/Ile and Glu/Lys ambiguities could be solved by either specific side-chain fragmentations or on-plate acetylation experiments. The identification of the specific sequences provides a solid basis for forthcoming pharmacological tests to study the neuroendocrine system of these pest insects. However, it should be mentioned in this context that the sequences of the peptides from different stinkbugs are likely not representative of Hemiptera in general. The forthcoming release of the genome from the reduviid Rhodnius prolixus will provide sufficient data to clear this point.