Abstract: In this study we extracted coelomic fluid of sea cucumber Apostichopus japonicus(95.0-105.0 g),collected plasma and haemocyte lysate(CLS)respectively,measured phenoloxidase(PO)activity and then analysed the induction of different activators to the proPO system.In addition,we compared PO activity of different sizes of sea cucumber.The results showed that PO activities of sea cucumber,varied among differentin dividuals(146.90± 55.60)U.There were no obvious change in PO activity after being inducedby different activities.The PO activity of CLS was 31.82 U,which could be increased by 100 mmol/L MgCl2induction.The activity of proPO was 43.9 U,PO activity had no obvious increase after treatments by LPS,SDS,CaCl2,Trypsin and methanol.SDS and Trypsin even showed inhibition effects.The findings suggested that PO of the coelomic fluid of sea cucumber was mainly distributed in plasma and proPO existed in coelomic cells which were greatly activated by Mg2+.PO activity of different sizes of sea cucumber(52.4-68.5,20.7-24.4 g and 4.9-5.6 g)were(42.18±7.62),(34.10± 9.28)U and(33.29±7.42)U respectively.It suggested that PO activity varied with different size of sea cucumber.Bigger individuals seemed showing higher PO activity.The PO activity of the maximal individuals(about 100 g)was significantly higher than that of the smaller ones(P＜0.05).
2013, Vol. 28 
