Identification of a CAPA-PVK [Ixori-PVK] from single cells of the gulf Gulf Coast tick, Amblyomma maculatum

MALDI-TOF/TOF tandem mass spectrometry has been applied to determine the complete sequence of a CAPA-PVK in the Gulf Coast tick, Amblyomma maculatum. Single cell analysis allowed the identification of the amino acid sequence of Ixori-PVK (PALIPFPRV-NH2), a periviscerokinin which had previously been identified from two other ticks, Ixodes ricinus and Boophilus microplus. The identification indicates greater conservation of sequence for the CAPA-PVK/CAP2b family in ticks as compared with insects. Side-chain fragmentation experiments provided data to distinguish between Leu/Ile ambiguities. The tick CAPA peptide shows a high sequence homology with other members of the insect periviscerokinin/ CAP2b peptides, which are associated with the regulation of critical physiological processes such as diuresis. Thus, the identification of this neuropeptide will provide the experimental basis to better understand regulation of water balance in these arthropods, providing a potential opportunity to develop neuropeptide-based control strategies against these livestock pests.