Endocytosis in microcystis aeruginosa accelerates the synthesis of microcystins in the presence of lanthanum(III).

Microcystis aeruginosa bloom releases microcystins (MCs) into global aquatic environment, which other living organisms can ingest the released MCs. The toxic effects of MCs on organisms are amplified through the food chain, threatening human and animal health. Lanthanum(III) [La(III)], a pollutant in aquatic environments worldwide, has been confirmed to stimulate MC synthesis in M. aeruginosa. However, the involved cellular mechanism remains unclear. Here, using interdisciplinary approaches, it was first observed that La(III) activated the clathrin-mediated endocytosis in M. aeruginosa. This allowed the algal cells to rapidly absorb macro-elements (C, N and P) and micro-elements (K, Ca and Mg) through the clathrin-mediated endocytosis. These in turn stimulated chlorophyll production, photosynthesis, the growth of the algal cells, and the increases in the productions of MC-LW, MC-LR and MC-YR in M. aeruginosa. These results provide valuable insights for understanding the involved cellular mechanism on MC synthesis and managing MC pollution, which is important to protect global food chain and the ecosystem.