溶藻细菌胞外活性物质对蛋白核小球藻的毒性效应

The Toxic Effects of the Extracellular Active Components from One Algae-lysing Bacteria on Chlorella Pyrenoidosa

摘要:

为了探索分离到的溶藻细菌L7胞外活性物质对蛋白核小球藻的毒性效应和致毒机理, 采用不同质量浓度的L7胞外活性物质冻干粉(L7-LPEAC)处理蛋白核小球藻(Chlorella pyrenoidosa), 测定藻细胞的光合作用效率(EPR)以及蛋白质、叶绿素a和丙二醛(MDA)的含量。L7-LPEAC溶液浓度较低(0.80 g/L和1.25 g/L)时促进蛋白核小球藻的生长, 其96 h、120 h的EC50分别为5.75 g/L和2.55 g/L。当L7-LPEAC溶液浓度≥2.00 g/L时, 叶绿素a和蛋白质含量变化同步呈现先增加后减少的趋势; 处理72 h后, L7-LPEAC溶液浓度分别为2.00 g/L, 3.13 g/L, 4.90 g/L的浓度组中, 藻细胞MDA含量与对照组相比差异显著(P<0.05), 浓度组7.67 g/L和12.00 g/L则与对照组差异极显著(P<0.01); 处理120 h后, 各浓度组藻细胞叶绿素a含量的相对抑制率均大于60%。使用L7-LPEAC修复富营养化水体时, 选择适当的投加浓度, 既能杀灭引起水体富营养化的目标藻类, 又能避免对其他藻类产生抑制作用, 可以较好地维持水生生态系统的平衡。

Abstract:

Toxic effects of L7 lyophilized powder of extracellular active components (L7-LPEAC), extracted from the Algae-lysing bacteria L7, on Chlorella pyrenoidosa were studied according to the changes of effective photosynthesis rate (EPR), the protein content, the chlorophyll a content and the MDA content of algae. The results showed that the growth of alga was promoted at low concentrations of L7-LPEAC (0.80 g/L, 1.25 g/L). The 96 h-EC50 and 120 h-EC50 upon Chlorella pyrenoidosa are 5.75 g/L and 2.55 g/L, respectively. The chlorophyll a content increased firstly and then decreased at high concentrations of L7-LPEAC (≥2 g/L), so did the protein content. Compared with the control group, there is a significant statistics difference (P<0.05) in the treatment groups (2.00 g/L, 3.13 g/L, 4.90 g/L), while extreme significant statistics difference (P<0.01) in the other treatment groups (7.67 g/L, 12.00 g/L) after 72 h. The inhibition rates of chlorophyll a content of Chlorella pyrenoidosa in all treatment groups reached over 60% after 120 h. For the remediation of eutrophic nature water body, it can not only kill the algae which caused the water eutrophication, but also maintain the balance of the aquatic ecosystem well by adding some proper concentrations of L7-LPEAC.