颗石藻藻源性二甲基硫丙酸（DMSP）在致死卤虫时的作用检测(The Detection of Lethal Effects of Algal Derived DMSP of Pleurochrysis carterea on Artemia salina)

颗石藻Pleurochrysis carterea具有显著致死卤虫的作用,但机理尚需进一步解明.为了分析颗石藻藻源性的二甲基硫丙酸(DMSP)及其分解产物二甲基硫(DMS)和丙烯酸是否是致死卤虫的原因所在,检测了P.carterae在受卤虫捕食压力情况下细胞DMSP及其裂解产物DMS的定量变化,以及外源DMSP、DMS和丙烯酸对卤虫的直接作用.结果显示,外源添加的高挥发性DMS对卤虫无节幼虫没有急性致死效应.外源重复添加浓度为0.08至1.0mM的DMSP和丙烯酸对卤虫的致死存在浓度和时间相关的效应,浓度越高发生卤虫大量死亡的时间越早.检测外源重复添加DMSP和丙烯酸时的pH变化发现,试剂重复添加会造成pH显著下降,这可能是致死卤虫真实的直接原因.捕食者与被捕食者系统中,检测颗石藻液中藻源性DMSP及裂解产物的定量水平并未达到显著致死卤虫的作用.但是,考虑颗石藻被卤虫重复捕食入体内的累积变化时,从理论值分析来看,颗石藻在卤虫体内的裂解可能对体内产生脉冲式的累积过低酸刺激,或许是造成卤虫的死亡原因.

The Detection of Lethal Effects of Algal Derived DMSP of Pleurochrysis carterea on Artemia salina

Pleurochrysis carterea has significant lethal effect on Artemia salina. However, the mechanism needs further explanations. In order to analyze whether the algal-derived DMSP and its degradation products DMS and acrylic acid are the reasons that cause the death of A. salina, the quantitative changes of DMSP and its cleavage products from P. carterae cell under the predation pressure of A.salina have been studied. The direct effects of DMSP, DMS and acrylic acid on A. salina have been studied as well. The results show that, no toxic effect was observed when high volatile DMS was introduced in the system. Concentration and time dependent lethal effects were observed when 0.08~1.0mM of DMSP or acrylic acid was repeatedly added to Artemia salina. However, from the results of the pH test, the repeatedly adding reagent caused significant decline in pH, which might be the direct reason for the death of A. salina. The amounts of cellular DMSP and its cleavage products did not reach the lethal level to A. salina. However, base on the theoretical calculations, the accumulation amounts of DMSP and related cleavage products inside A. salina were significant to cause low pH pulses, which might be a reason that caused the death of A. salina.