Vézie C, Rapala J, Vaitomaa J, Seitsonen J, Sivonen K
Department of Applied Chemistry and Microbiology, Division of Microbiology, Biocenter Viikki, FIN-00014 Helsinki University, Finland.
Microb Ecol. 2002 May;43(4):443-54. doi: 10.1007/s00248-001-0041-9. Epub 2002 Apr 15.
The growth and intracellular microcystin concentration of two hepatotoxic and two nontoxic axenic Microcystis strains were measured in batch cultures with variable nitrogen (0.84-84 mg L(-1)) and phosphorus (0.05-5.5 mg L(-1)) concentrations. Growth was estimated by measuring dry weight, optical density, chlorophyll a, and cellular protein concentration. Microcystin concentrations in cells and in culture medium were measured by HPLC analysis. Both nontoxic strains needed less nutrients for their growth at low nutrient concentrations. With high nutrient concentrations the toxic strains grew better than the nontoxic strains. Growth and intracellular microcystin concentration did not correlate in the hepatotoxic strains. Multivariate regression analysis together with mathematical modeling revealed a significant interactive effect of nitrogen and phosphorus, which partly explains the controversial results obtained in previous studies. In this study we have shown that variation of nitrogen and phosphorus concentrations influence the growth and the microcystin production of Microcystis strains and that the strains differ in their response to nutrients. High levels of nitrogen and phosphorus in freshwaters may favor the growth of toxic Microcystis strains over nontoxic ones.
在氮浓度（0.84 - 84毫克/升）和磷浓度（0.05 - 5.5毫克/升）可变的分批培养中，测定了两种产肝毒素的无菌微囊藻菌株和两种无毒无菌微囊藻菌株的生长情况及细胞内微囊藻毒素浓度。通过测量干重、光密度、叶绿素a和细胞蛋白浓度来估算生长情况。通过高效液相色谱分析测定细胞和培养基中的微囊藻毒素浓度。在低营养浓度下，两种无毒菌株生长所需的营养较少。在高营养浓度下，产毒菌株比无毒菌株生长得更好。产肝毒素菌株的生长与细胞内微囊藻毒素浓度没有相关性。多变量回归分析和数学建模显示氮和磷存在显著的交互作用，这部分解释了先前研究中得到的相互矛盾的结果。在本研究中，我们表明氮和磷浓度的变化会影响微囊藻菌株的生长和微囊藻毒素的产生，并且不同菌株对营养物质的反应存在差异。淡水中高含量的氮和磷可能有利于产毒微囊藻菌株而非无毒菌株的生长。
