Studies on species-and self-recognition in scleractinian corals

研究了珊瑚Pocillopora Damicoris的组织相容性反应的发育变化和从不相容融合到非融合的细胞学机制。来自不同珊瑚群体的初级息肉或幼虫在定居后几天内接触，它们要么表现为融合，要么表现为不相容融合。当从成虫群体分离出来的分支接触时，它们要么融合，要么不融合。目前的结果表明，珊瑚在发育早期不具有避免组织融合的功能组织相容性系统。几个月后，显示不相容融合的细胞转化为不融合或断开。在不相容融合对的界面处可见较大的胞外间隙和核固缩，胞浆较少。这表明，在从不相容融合到非融合的转变过程中，界面上的细胞通过凋亡而死亡，并被吞噬。利用不同种类的珊瑚，比较了线虫囊排出反应和肠外消化反应的敏感性。在一些珊瑚物种组合中，珊瑚不对目标珊瑚释放线虫囊，而它们利用肠系膜细丝表现出攻击性行为。这表明珊瑚可能使用不同的标记来区分异种珊瑚和同种珊瑚。

Developmental changes in histocompatibility reactions and the cellular mechanism of transformation from incompatible fusion to nonfusion in the coral Pocillopora damicornis were studied.When primary polyps or young colonies derived from different colonies of a coral, P.damicornis were brought into contact within a few days after settlement, they showed either fusion or incompatible fusion. When branches isolated from adult colonies were brought into contact they showed either fusion or nonfusion. The present results suggest that the coral do not have functional histocompatibility system to avoid tissue fusion at an early stage of development.Pairs that show incompatible fusion transformed into nonfusion or disconnection after several months. Large extracellular spaces and cells with condensed nuclei and small amount of cytoplasm were observed at the interface of incompatibly fused pairs. This suggests that cells at the interface died through apoptosis and were phagocitized during the transformation from incompatible fusion to nonfusion.Sensitivity of nematocyst discharge response and that of extracoelenteric digestion response were compared using various coral species. In some combination pf coral species, corals did not discharge nematocysts against target corals, while they display aggressive behavior using mesenterial filaments. This suggests the possibility that coral use different markers to distinguish allogeneic from xenogeneic corals.