| Summary: | 碩士 === 國立中興大學 === 昆蟲學系 === 87 === Several partial cDNAs were amplified from the total RNA of the abdomens of the oriental fruit fly, Bactrocera dorsalis（Hendel）, using degenerate primers which were derived from the amino acid sequences of the yolk protein genes of Ceratitis capitata ( CcVg1 ), Anastrepha suspensa ( AsYP ), and Drosophila melanogaster ( DmYP ) and reverse transcription polymerase chain reaction ( RT-PCR ). One of these cloned cDNA fragments showed the high neuclic acid sequence homology to the referred insects' yolk protein genes. The identites of the predicted amino acid sequence of the clone are 79.7 % to CcVg1, 65.8 % to AsYP, and 60.8 % to DmYP1, indicating that the cloned cDNA fragment is a part of one of B. dorsalis yolk protein gene.
Northern blot studies revealed that the cloned cDNA probe specifically hybridized a single band with RNA in females but not males; and the estimated size of the band was between 1.5 and 2.0 kb. The partial cDNA, named BdYP1, was determined using overlapping cDNA fragment from RACE reactions. This partial cDNA of BdYP1 was 1,494 bp long. The identities of the predicted amino acid sequence of BdYP1 between overlapping sequences were 66.6 % to CcVg1, 61.2 % to AsYP, and 50.2 % to DmYP1.
Using the degenerate primers to detect the aboudence of BdYP1-mRNA in B. dorsalis by RT-PCR showed that the minute amounts of BdYP1 expressed in the all stages of B. dorsalis; and only in female adults, the BdYP1 expression significantly increased since day two and after. Furthermore, the BdYP1 transcripts were detected in the heads, throaxes and abdomens of adult flies. In addition, the BdYP1 expression was detected in the 6-day-old males. The effects of juvenile hormone analog, methoprene, on BdYP1 expression was examined, and the results showed that application of 1 mg methoprene stimulated BdYP1 expression in 6 hr in comparison with the untreated flies. Furthermore, treatments on males with 1mg methoprene were increased the expression of BdYP1 as well, however, it showed much lower response than in females. The controversial results based on Northern blot and RT-PCR were probably due to the high sensitivity of PCR amplification reaction.
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