Elucidation of Endocrinological Mechanisms during Tick Vitellogenesis

• Project/Area Number: 16580035
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Applied entomology
• Research Institution: University of Tsukuba
• Principal Investigator: TAYLOR De Mar University of Tsukuba, Graduate School of Life and Environmental Sciences, Assistant Professor, 大学院・生命環境科学研究科, 講師 (50261772)
• Co-Investigator(Kenkyū-buntansha): CHINZEI Yasuo Mie University, School of Medicine, Department of Medical Zoology, Professor, 医学部, 教授 (60024709)
• Project Period (FY): 2004 – 2005
• Project Status: Completed (Fiscal Year 2005)
• Budget Amount: ¥3,700,000 (Direct Cost: ¥3,700,000); Fiscal Year 2005: ¥1,200,000 (Direct Cost: ¥1,200,000); Fiscal Year 2004: ¥2,500,000 (Direct Cost: ¥2,500,000)
• Keywords: vitellogenesis / soft tick / Ornithodoros moubata / ecdysone / endocrinology / gene expression / ecdysteroid receptor / retinoid X receptor / 内分泌的 / ビテロジェニン / エクダイステロイドレセ / エクジソン受容体 / DNA

Research Abstract

Vitellogenesis appears to be regulated by ecdysteroids in ticks. Ecdysteroids may function by forming a complex with a heterodimer of two nuclear receptors, ecdysteroid receptor (EcR) and retinoid X receptor (RXR). In previous studies, mated females of Ornithodoros moubata showed several peaks of high ecdysteroid titers with vitellogenin (Vg) synthesis and egg maturation after engorgement, whereas virgin females showed very low levels of ecdysteroids with no peaks, lower levels of Vg synthesis and no egg maturation. These results indicate a role for ecdysteroids in the regulation of tick Vg synthesis and egg maturation but in order to clarify this role in O.moubata we compared the EcR and RXR expression patterns in vitellogenic mated and virgin female ticks by real-time PCR. EcR and RXR expression increased soon after blood feeding in both mated and virgin females. EcR and RXR expression in mated females coincided with the high ecdysteroid titers in hemolymph. A lack of differences in EcR and RXR expression in mated and virgin females with increased ecdysteroid titers in only mated females provides further support that Vg synthesis and egg maturation are regulated by ecdysteroids.

Research Products

• [Journal Article] Ecdysteroid Hormone Titer and its Relationship to Vitellogenesis in the Soft Tick, Ornithodoros moubata (Acari : Argasidae) (2006)
  • Author(s): Ogihara, K., M.Horigane, A.Moribasyashi, D.Taylor
  • Journal Title: General and Comparative Endocrinology (In Submission)
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Ecdysteroid Hormone Titer and its Relationship to Vitellogenesis in the Soft Tick, Ornithodoros moubata (Acari : Argasidae). (2006)
  • Author(s): Ogihara, K., M.Horigane, A.Moribasyashi, D.Taylor.
  • Journal Title: General and Comparative Endocrinology (In Submission)
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Ecdysteroid Hormone Titer and its Relationship to Vitellogenesis in the Soft Tick, Ornithodoros moubata (Acari : Argasidae) (2006)
  • Author(s): Ogihara, K., M.Horigane, A.Moribayashi, D.Taylor
  • Journal Title: General and Comparative Endocrinology (In submission)
• [Journal Article] Vitellogenesis in Ticks, Chapter 6. (2002)
  • Author(s): Taylor, D., Y.Chinzei.
  • Journal Title: Reproductive Biology of Invertebrates, Volume XII -Recent Progress in Vitellogenesis, (K.G.Adiyodi and R.G.Adiyodi (Series Editors). A.S.Raikhel and T.W.Sappington (Volume Editor))(Science Publishers, Inc., Enfield (NH), USA.) Pages: 175-199
  • Description: 「研究成果報告書概要(欧文)」より
• [Book] Reproductive Biology of Invertebrates, Volume XII - Recent Progress in Vitellogenesis (K.G. Adiyodi and R.G. Adiyodi (Series Editors)) (A.S. Raikhel and T.W. Sappington (Volume Editor)) (2002)
  • Author(s): Taylor, D., Y.Chinzei
  • Publisher: Science Publishers, Inc., Enfield (NH), USA.
  • Description: 「研究成果報告書概要(和文)」より