Objective: To study the variation of polysaccharide (PS), which can be classified as capsule polysaccharide (EPS) and extracellular polysaccharide (EPS), and microcystin-RR (MC-RR) content of Microsystis aeruginosa under the stress of salicylic acid (SA).
Methods: 0, 0.25, 0.50, 0.75 and 1.00 mmol/L SA were added into the culture of M. aeruginosa at logarithmic phase and the contents of PS and MC-RR were quantified by phenol-sulfuric acid method and high performance liquid chromatography (HPLC) method in the 6th and 12th day. Meanwhile the effect of SA on PS and MC-RR contents were discussed at both the level of single cell and that of whole culture medium.
Results: CPS contents were increased with the increasing concentration of SA on the 6th day and decreases on the 12th day. The content of EPS and intracellular MC-RR first increases and then decreases with the increasing SA concentration in the whole stage.
Conclusion: The contents of CPS and MC-RR increase for the stress of SA in early days, and then the contents of MC-RR both inside and outside the cell are decrease.