卵圆卡盾藻溶血毒素产毒的影响因素研究

Study on the hemolytic activity of Chattonella ovata

研究了卵圆卡盾藻（Chattonella ovata）在不同环境因子下的溶血活性特征。根据卵圆卡盾藻的生长曲线,分别收集对数生长期、稳定期、衰亡期的藻细胞进行溶血毒性的测定。采用不同温度、盐度和营养元素结构的培养基对卵圆卡盾藻进行培养,对不同培养条件下的藻细胞进行溶血活性的测定。结果表明,卵圆卡盾藻衰亡期藻细胞的溶血活性最强,达到29.5×10-7HU/cell（HU,Hemolytic Unit,溶血单位）,其次为对数生长期（21.9×10-7HU/cell）。在10~25℃培养条件下,温度对藻细胞溶血活性无显著影响;在盐度15~25 psu范围内,藻细胞溶血活性变化不明显,而高盐度（33 psu）能够刺激溶血毒素的产生。在Fe限制时,藻细胞溶血活性最强（37.4×10-7HU/cell）,为正常培养条件下（f/2培养基）溶血活性值（18.8×10-7HU/cell）的2.0倍;其次为P限制,藻细胞的溶血活性值为24.1×10-7HU/cell;N、Mn限制条件下藻细胞溶血活性与正常培养条件无显著性差异。

Chattonella ovata（C.ovata）,a raphidophycean flagellate,is a causative organism of red tide,which is highly toxic and harmful to fish breeding and growth.In this study,we have traced and explored the hemolytic activities of C.ovata in different environmental conditions in the lab-controlling conditions.According to the growth curve of C.ovata,we have collected the cells in culture in the logarithmic phase,stationary phase and declining phase,respectively,so as to determine the hemolytic activities of C.ovata,which are cultured at different temperatures,salinity and nutrients structures. The results of experiments and observation show that C.ovata was acclimated in culture tanlogks for 2-4 days and grew to logarithmic phase in 6 days.C.ovata was in the stationary phase from 12 d to 14 d.The highest hemolytic activity can be found in the declining phase,which can be counted for 29.5×10-7 HU/cell.As to its Hemolytic activity in the logarithmic phase（21.9×10-7 HU/cell）,it can be found that it was lower than that in the declining phase.The lowest hemolytic activity of C.ovata（14.5×10-7 HU/cell） was observed in the stationary phase.The temperature from 10 ℃ to 25 ℃ doesn＇t seem to have significant effect on the hemolytic activity of C.ovata,which ranged from 22.0×10-7-23.2×10-7 HU/cell.We have also found that the hemolytic activity fluctuations didn＇t change significantly with its salinity from 15 to 25 psu,while it increased to 21.9×10-7 HU/cell,with the highest value among the experiments at the salinity of 33 psu.In addition, it has been found that the nutrient structure may greatly influence the hemolytic activity of C.ovata,which is 18.8×10-7 HU/cell under the f/2 culture.In addition,Fe limitation is found to enhance the hemolytic activity of C.ovata greatly,i.e.37.4×10-7 HU/cell,about 2.0 times higher than that with no Fe limitation（the f/2 culture）.In the similar way,P limitation could also help to enhance the hemolytic activity of C.ovata to 24.1×10-7 HU/cell.However,the hemolytic activity of C.ovata with N and Mn limitation,that is,19.9×10-7 HU/cell and 16.7×10-7 HU/cell,respectively,proves to make no significant difference with that of the f/2 culture.