金乌贼(Sepia esculenta)早期发育阶段相关酶活性的变化

Changes in Activities of Related Enzymes in Early Developmental Stages of Sepia esculenta

采用生化方法测定了金乌贼(Sepia esculenta)不同发育阶段的受精卵以及0–10日龄幼体的胰蛋白酶、胃蛋白酶、碱性磷酸酶、脂肪酶和谷丙转氨酶5种酶比活力的变化。结果显示,可溶性蛋白浓度总体呈先上升后下降再上升的变化趋势,其中,在囊胚和原肠期(Ⅱ)最高,在初孵幼体(Ⅶ)中最低,含量分别为81.50 mg/g和4.24 mg/g。胰蛋白酶、胃蛋白酶和谷丙转氨酶比活力的变化趋势相近,总体呈先上升后下降再上升的变化趋势,其中,在胚胎发育阶段均能检测出这3种酶的活性,说明主要自母体获得,但活力相对较低;在初孵幼体中,这3种酶活性均显著升高,比活力分别为0.51 U/g、1.68 U/mg和37.84 U/g;5日龄幼体(Ⅷ)中,3种酶比活力均显著下降至出膜前水平;10日龄幼体(Ⅸ)中,3种酶比活力均有小幅度上升。碱性磷酸酶和脂肪酶比活力的变化趋势相近,总体呈上升趋势,其中,在胚胎发育阶段仅检测到这2种酶的极低活性,幼体孵出后2种酶的比活力才显著上升,标志着器官发育的逐步完善和消化能力的逐步增强。

Chemical and biological methods were employed to determine specific activities of several enzymes including trypsin, pepsin, alkaline phosphatase （AKP）, lipase, and alanine aminotransferase （ALT） at different stages of fertilized eggs and 0-10 days old larvae of golden cuttlefish Sepia esculenta. The results showed that the soluble protein content was elevated in the early embryonic and larval stages, but was depressed from the mid to late embryonic stages. The protein content was the highest in the blastula and gastrulae stage（ II ） （81.50 mg/g）, and the lowest in the newly-hatched larvae （VII） （4.24 mg/g） During the development, the specific activities of trypsin, pepsin, and ALT in five enzymes all followed the up-down-up pattern. Activities of all three enzymes were detectable but very low in embryonic developmental stages, suggesting their maternal originality. Moreover, the enzymatic activities were significantly increased in newly-hatched larvae, which were 0.51 U/g, 1.68 U/mg and 37.84 U/g respectively The enzymatic activities in 5 days old larvae （Ⅷ） dropped significantly compared to the level before hatching, and rose slowly in 10 days old larvae （Ⅸ）. The activities of both AKP and lipase were generally elevated, starting from very low during the embryonic stages to significantly higher after hatching. These results implied the gradual maturation of organs and the improvement of digestion capability.