| Budget Amount *help |
¥15,700,000 (Direct Cost: ¥15,700,000)
Fiscal Year 2006: ¥4,300,000 (Direct Cost: ¥4,300,000)
Fiscal Year 2005: ¥4,500,000 (Direct Cost: ¥4,500,000)
Fiscal Year 2004: ¥6,900,000 (Direct Cost: ¥6,900,000)
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| Research Abstract |
1. Hemolymph titers of juvenile hormone (JH) and ecdysteroids in the fed and starved larvae of the yellow-spotted longicorn beetle, Psacothea hilaris, were measured. Starvation induced a rapid decrease in JH titer, and it appeared that this decrease induces a small peak of ecdysteroids, which in turn paves way to precocious metamorphosis.
2. cDNA (PhJHE) of the gene encoding JH esterase, which plays a key role in controlling the JH titer in the hemolymph, was cloned from P.hilaris. The ORF of PhJHE consisted of 1785 base pairs, and encoded a protein of 595 amino acids.
3. Differential display (DD) technique was used to find differentially expressed genes under the conditions which induce precocious metamorphosis. A band that showed a change in DD was found to show a high similarity to known sequences of β-N-acetylglucosaminidase. The estimated ORF of this gene (PhNag) consisted of 1815 bp. PhNag was highly expressed in the 4th and 5th instar individuals that are experimentally destined to pupate under feeding conditions, and the 4th instar individuals that are destined to pupate under starved conditions. Based on the sequence of PhNag, it is inferred that this enzyme is "chitin decomposing type".
4. We cloned Broad-Complex gene (BR-C), which is one of the early genes responsive to 20-hydroxyecdysone (20HE), from P.hilaris (PhBR-C). In Drosophila, four isoforms (Z1, Z2, Z3 and Z4) are known to be produced by differential splicing of the zinc-finger domain. In the present study, we found two isoforms similar to Drosophila Z1 and Z4 from P.hilaris. Quantitative real-time PCR analyses have shown that the expression of PhBR-C in the brain, salivary gland, and epidermis increased as the larvae entered gut purge and prepupal stages.
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