Cell Death and Metabolic Stress in <i>Gymnodinium catenatum</i> Induced by Allelopathy

• Main Authors: Leyberth José Fernández-Herrera, Christine Johanna Band-Schmidt, Tania Zenteno-Savín, Ignacio Leyva-Valencia, Claudia Judith Hernández-Guerrero, Mauricio Muñoz-Ochoa
• Format: Article
• Language: English
• Published: MDPI AG 2021-07-01
• Series: Toxins
• Subjects: allelopathy; apoptosis; caspase-3; harmful algae; reactive oxygen species
• Online Access: https://www.mdpi.com/2072-6651/13/7/506

Allelopathy between phytoplankton species can promote cellular stress and programmed cell death (PCD). The raphidophyte <i>Chattonella marina</i> var. <i>marina</i>, and the dinoflagellates <i>Margalefidinium polykrikoides</i> and <i>Gymnodinium impudicum</i> have allelopathic effects on <i>Gymnodinium catenatum</i>; however, the physiological mechanisms are unknown. We evaluated whether the allelopathic effect promotes cellular stress and activates PCD in <i>G. catenatum</i>. Cultures of <i>G. catenatum</i> were exposed to cell-free media of <i>C. marina</i> var. <i>marina</i>, <i>M. polykrikoides</i> and <i>G. impudicum</i>. The mortality, superoxide radical (O₂^●−) production, thiobarbituric acid reactive substances (TBARS) levels, superoxide dismutase (SOD) activity, protein content, and caspase-3 activity were quantified. Mortality (between 57 and 79%) was registered in <i>G. catenatum</i> after exposure to cell-free media of the three species. The maximal O₂^●− production occurred with <i>C. marina</i> var<i>. marina</i> cell-free media. The highest TBARS levels and SOD activity in <i>G. catenatum</i> were recorded with cell-free media from <i>G. impudicum</i>. The highest protein content was recorded with cell-free media from <i>M. polykrikoides</i>. All cell-free media caused an increase in the activity of caspase-3. These results indicate that the allelopathic effect in <i>G. catenatum</i> promotes cell stress and caspase-3 activation, as a signal for the induction of programmed cell death.