Abstract
Helicoverpa assulta suboesophageal ganglion neuropeptide I (Has-SGNP I) is a 24-amino acids peptide amide, which shows 62.5% similarity with the diapause hormone of Bombyx mori (Bom-DH). It has been demonstrated that embryonic diapause is induced by DH in B. mori. Injection of synthetic amidated Has-SGNP I terminated pupal diapause in a dose-dependent manner. Therefore, Has-SGNP I might be referred to a “diapause termination hormone” in H. assulta (Has-DTH). The maximal dose of Has-DTH for diapause termination was 1.0 μg and the half-maximal dose 0.4 μg. The time required for diapause termination of Has-DTH was 2–3 days longer than that of 20-hydroxyecdysone. During the pupal stage, DTH mRNA content in the SGs of nondiapausing pupae was always higher than in diapausing pupae using the combined method of quantitative RT-PCR and Southern blot. DTH gene also expressed at a low level while diapausing pupae were chilled at 4 °C, but increased rapidly and largely after being transferred to 25 °C. Using a competitive ELISA, Has-DTH-like immunoreactivity in the haemolymph showed the same pattern as that of Has-DTH gene expression. Those results indicated that Has-DTH gene expression was related to diapause development and could be activated by low temperature. Has-DTH might be useful to elucidate the mechanism of diapause termination in pupal diapause species.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
