Ecdysone 20‐monooxygenase in eggs of the silkworm, Bombyx mori: Enzymatic properties and developmental changes
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Abstract The present study provides novel information on the presence of compounds with ecdysone‐like activity and its involvement in the control of gonadal development in a leech. The presence of ecdysone was demonstrated in leech ( Nephelopsis obscura ) extract by means of high‐performance liquid chromatography (HPLC) in combination with radioimmunoassy. Leech extract was found to bind specifically to an anti‐ecdysone antiserum in a similar manner as standard ecdysone. Further HPLC purification demonstrated the presence of an immunoreactive fraction coeluting exactly with the standard ecdysone, strongly suggesting the presence of ecdysone in N. obscura . Addition of ecdysone to the ambient medium not only advanced leech gametogenesis but also influenced energy utilization. Both low (60 μg·L −1 ) and high (600 m̈g·L −1 concentrations of ecdysone increased testisac number, spermatogonia, 4th stage spermatogonia, ovisac size, and 2nd stage oogonia within 14 days compared to 35 days in the controls. Ecdysone also caused significant decreases in glycogen, total lipid, and triacylglycerols correlated with the energetic demands of gametogenesis. The findings provide support for the hypothesis that endogenous ecdysone is involved in the regulation of reproduction in N. obscura . © 1995 Wiley‐Liss, Inc.
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Callus
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Ecdysteroid
Bombycidae
20-Hydroxyecdysone
Bombyx
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From ovaries dissected from developing and emerged adults of the silkworm, Bombyx mori, two substances having high molting hormone activity were isolated. One of these was identified as 2-deoxy-alpha-ecdysone by means of high-pressure liquid chromatography and mass spectrometry. Although this compound had previously been isolated from the fern Blechnum minus and postulated to be the precursor of alpha-ecdysone, it had not been obtained from insect material. The compound is also contained in the form of a conjugate in ovaries as well as in diapausing silkworm embryos.
Bombyx
Bombycidae
Conjugate
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Adult eclosion of the silkworm, Bombyx mori, occurs during a specific period of the day under the control of eclosion hormone (EH). Bombyx EH was extracted from the pupal and adult brains (Fugo, et al., 1982), and also the embryos of B. mori (Chen, et al., 1986). In 1985, Bombyx EH was first isolated from the pharate adult heads of B. mori (Nagasawa, et al., 1985). Recently the entire amino acid sequence of Bombyx EH was determined as shown in Fig. 1 through the combination of sequencing the isolated Bombyx EH (Kono, et al., 1987) and cloning the Bombyx EH gene. A monoclonal antibody against the synthetic peptide corresponding to the carboxyl-terminal 13 amino acid residues of Bombyx EH was prepared (Kono, et al., in press).
Bombyx
Bombycidae
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Bombyx
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