Vitellogenesis Induction by Synganglion Factor in Adult Female Tick, Ornithodoros moubata (Acari: Argasidae)

Chinzei, Y., D. Taylor, K. Miura and K. Ando, 1992. Vitellogenesis induction by synganglion factor in adult female tick, Ornithodoros moubata(Acari: Argasidae). J. Acarol. Soc. Jpn., 1(1): 15-26.Vitellogenesis, vitellogenin(Vg)induction in the hemolymph and ovarian development, was studied in unengorged female adults injected with synganglion(SyG)extract and treated with cypermethrin(CyM)in the tick, Ornithodoros moubata(Acari, Argasidae). CyM induced Vg in the hemolymph in the anterior parts of ligated females which contain the SyG, but did not induce vitellogenesis in the posterior part. This result suggests that the SyG is stimulated by treatment with CyM to release a factor for inducing vitellogenesis(vitellogenin inducing factor=VIF). We showed the injection of SyG extracts prepared from unengorged females induced a significant increase of Vg in the hemolymph and ovarian development, but that of SyG extracts from engorged females did not. This indicates that the unengorged female SyG contains the factor, VIF, which is released during or after engorgement. This SyG factor was sensitive to proteases, trypsin and chymotrypsin, indicating the factor is a peptide.