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item Neupert, Susanne
item Predel, Reinhard
item Russell, William
item Davey, Ronald
item Pietrantonio, Patricia
item Nachman, Ronald - Ron

Submitted to: Biochemical and Biophysical Research Communications
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/20/2005
Publication Date: 11/1/2005
Citation: Neupert, S., Predel, R., Russell, W.K., Davey, R.B., Pietrantonio, P.V., Nachman, R.J. 2005. Identification of tick periviscerokinin, the first neurohormone of Ixodidae: Single cell analysis by means of MALDI-TOF/TOF mass spectrometry. Biochemical and Biophysical Research Communications. 338:1860-1864.

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 tick pests. The basic premise of this research is that neuropeptides (short chains of amino acids) serve as potent messengers in insects and ticks 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 or tick. We report on the use of state-of-the-art analytical techniques to unambiguously characterize the structure of the first regulatory neuropeptide of a species of tick via direct analysis of a single organ. The subject of this investigation is the Southern Cattle Fever tick, a pest of livestock in the US. A deeper understanding of the specific structures of neuropeptides, where they are stored and released, and how these neuropeptides regulate critical processes in ticks will aid in the design of strategies to disrupt feeding and survival. The work brings us one step closer to the development of practical neuropeptide-like substances that will be effective in controlling pest ticks in an environmentally friendly fashion.

Technical Abstract: The first peptidergic neurohormone from ticks has been identified by using a combination of immunocytochemistry and mass spectrometric analysis of single cells. The novel peptide (Ixori-PVK, PALIPFPRV-NH2) shows a high sequence homology with members of the insect periviscerokinin/CAP2b peptides which, in insects, are involved in the regulation of water balance. The function of this peptide in ticks is still unknown, but these pests consume large amounts of blood in a single blood meal which is a challenge for the regulation of diuretic processes. Thus, the novel peptide may be involved in one of the key physiological processes in ticks. High energy collision-induced dissociation was successfully used to distinguish between Leu/Ile ambiguities in single cell preparations. We also found that Ixori-PVK is expressed in other tick as well.