Enzymatically prepared alginate oligomer (AO) promoted the growth of Chlamydomonas
reinhardtii in a concentration-dependent manner. AO at 2.5 mg/mL induced increase
in expression levels of cyclin A, cyclin B, and cyclin D in C. reinhardtii. CuSO4
at 100 μM suppressed the growth of C. reinhardtiin, and AO at 2.5 mg/mL significantly
alleviated the toxicity of CuSO4. Increased intracellular reactive oxygen species
level in C. reinhardtii induced by CuSO4 was reduced by AO. After cultivation with
CuSO4 at 100 μM, expression levels of ascorbate peroxidase and superoxide dismutase
in C. reinhardtii were increased, and AO reduced the increased levels of these enzymes.
These results suggest that AO exhibits beneficial effects on C. reinhardtii through
influencing the expression of various genes not only at normal growth condition but
also under CuSO4 stress.