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Expression of pancreatic enzyme genes during the early larval stage of Japanese eel Anguilla japonica 总被引：1，自引：0，他引：1
TADAHIDE KUROKAWA TOHRU SUZUKI HIROMI OHTA HIROHIKO KAGAWA HIDEKI TANAKA TATSUYA UNUMA 《Fisheries Science》2002,68(4):736-744
ABSTRACT: To reveal the ontogeny of pancreatic exocrine function in the early larval stage of eel, cDNAs encoding major pancreatic enzymes, trypsinogen, amylase and lipase were identified from the Japanese eel Anguilla japonica and their expression pattern in larvae was analyzed. The cloned eel trypsinogen precursor consisted of 224 amino acids and showed 82.2% identity to trypsinogen-2 of winter flounder Pleuronectes americanus . The eel amylase precursor consisted of 512 amino acids and showed 77% identity to winter flounder amylase. Eel pancreatic lipase was composed of 470 amino acids and had 58.3% of identity to human pancreatic lipase. In the eel larvae, mRNA expression of trypsinogen and amylase was first detected at 6 days post-hatching (d.p.h.), and the expression level increased between 7 and 8 d.p.h. In contrast, mRNA expression of lipase was first detected at 8 d.p.h. Eel larvae start to feed actively at 8 d.p.h. Thus, it was indicated that eel pancreas starts to synthesize digestive enzymes at 6 d.p.h. and acquires full function by the onset of exogenous feeding at 8 d.p.h. 相似文献
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HIROHIKO KAGAWA HIDEKI TANAKA TATSUYA UNUMA HIROMI OHTA KOICHIRO GEN KOICHI OKUZAWA 《Fisheries Science》2003,69(2):234-241
ABSTRACT: The in vitro effects of 17,20β-dihydroxy-4-pregnen-3-one(DHP) and prostaglandins (PGE1 , PGE2 , PGF1α ,PGF2α ) on ovulation in the Japanese eel Anguillajaponica were examined. Oocytes with follicle layers at themigratory nucleus stage (approximately 850–900 µmdiameter) were removed using a polyethylene cannula from artificiallymatured fish. At concentrations of 10 and 100 ng/mL,DHP was found to induce both germinal vesicle breakdown and ovulation.The prostaglandins, except for PGE1 , effectively inducedovulation of previously matured oocytes by DHP treatment in vitro .Prostaglandin F2α was the most effective. Asignificant increase in ovulation rate was observed even at a concentrationof 0.01 µg/mL PGF2α .Indomethacin blocked the in vitro ovulation induced by DHPand addition of PGF2α reversed indomethacin-blockedovulation. Actinomycin D and cycloheximide blocked DHP-induced ovulationand PGF2α reversed the effects of both inhibitors. Theseresults indicate that DHP induces ovulation through endogenous prostaglandinsynthesis in the follicle layers of the Japanese eel. 相似文献
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Changes in fertility of rainbow trout eggs retained in coelom 总被引：1，自引：0，他引：1
TERUO AZUMA HIROMI OHTA SABURO ODA KOJI MUTO TAKASHI YADA TATSUYA UNUMA 《Fisheries Science》2003,69(1):131-136
ABSTRACT: Effects of prolonged retention time of ovulated eggs in the parental coelom on fertilization success were studied in rainbow trout Oncorhynchus mykiss using cryopreserved sperm with a uniform fertilizing ability. Proportions of successful fertilization, eyed eggs and hatched alevins were examined at different time periods up to a retention time of 14 days beyond the ordinary stripping time, and were compared with eggs incubated in artificial coelomic fluids (ACF). Eggs that were retained longer in the coelom showed gradual decreases in all the proportions of successful fertilization, eyed eggs and hatched alevins. The progress of cleavage after fertilization slowed with prolonged retention times. Eggs incubated in ACF lost their fertilizing ability much sooner than those retained in the coelom. The hatching rate of eggs retained for 2 weeks in coelom was 36%, while it was 1% in those eggs incubated for 4 days in ACF. Thus, eggs retained in the coelom showed higher fertilization success than those incubated in ACF. 相似文献
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