Understanding\nthe Molecular Mechanisms of Pyrene in\nGoverning the Critical Metabolic Circuits of Alexandrium\npacificum

Pyrene,\na representative polycyclic aromatic hydrocarbon, frequently\noccurs in aquatic environments and is associated with lethal impacts\non humans and wildlife. This study examined the impact of pyrene on Alexandrium pacificum, a dinoflagellate responsible\nfor harmful algal blooms, and their capability to bioremove pyrene.\nIn a 96 h exposure experiment, A. pacificum effectively reduced the pyrene concentration in seawater to 50,\n100, and 200 μg/L, with a combined removal efficiency of 96%\nin seawater. Furthermore, the study noted a significant reduction\nin the synthesis of GTX4, GTX1, NEO, and GTX3 toxins in A. pacificum cells exposed to 50 and 200 μg/L\nof pyrene. Concurrently, exposure to pyrene resulted in marked declines\nin the growth and photosynthetic efficiency of A. pacificum. Proteomics analysis results showed an upregulation of proteins\nrelated to endocytosis, such as HSPA and Arf, while proteins associated\nwith paralytic shellfish toxin (PST) synthesis, specifically SxtU\nand SxtH, showed a downregulation trend. In summary, the findings\nof this study preliminarily elucidate the molecular mechanisms underlying A. pacificum’s response to pyrene, reveal\nthe impact of pyrene on PST synthesis, and suggest that A. pacificum holds significant potential for pyrene\nbiodegradation.