Programmed cell death of the dinoflagellate Peridinium gatunense is mediated by CO2 limitation and oxidative stress

Assaf Vardi, Ilana Berman-Frank, Taly Rozenberg, Ora Hadas, Aaron Kaplan, Alex Levine

Research output: Contribution to journalArticlepeer-review

Abstract

The phytoplankton assemblage in Lake Kinneret is dominated in spring by a bloom of the dinoflagellate Peridinium gatunense, which terminates sharply in summer [1]. The pH in Peridinium patches rises during the bloom to values higher than pH9 [2] and results in CO2 limitation. Here we show that depletion of dissolved CO2 (CO2(dis)) stimulated formation of reactive oxygen species (ROS) and induced cell death in both natural and cultured Peridinium populations. In contrast, addition of CO2 prevented ROS formation. Catalase inhibited cell death in culture, implicating hydrogen peroxide (H2O2) as the active ROS. Cell death was also blocked by a cysteine protease inhibitor, E-64, a treatment which stimulated cyst formation. Intracellular ROS accumulation induced protoplast shrinkage and DNA fragmentation prior to cell death. We propose that CO2 limitation resulted in the generation of ROS to a level that induced programmed cell death, which resembles apoptosis in animal and plant cells. Our results also indicate that cysteine protease(s) are involved in processes that determine whether a cell is destined to die or to form a cyst.

Original languageEnglish
Pages (from-to)1061-1064
Number of pages4
JournalCurrent Biology
Volume9
Issue number18
DOIs
StatePublished - 23 Aug 1999
Externally publishedYes

Bibliographical note

Funding Information:
This research was supported by grants to A.K. and A.L from the Israel Academy of Sciences and the USA–Israel Binational Science foundation, and by a grant from the German Federal Ministry of Education, Science, Research and Technology and the Israel Ministry of Science under contract DISUM 40. We thank N. Melamed-Book for confocal analysis.

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology (all)
  • Agricultural and Biological Sciences (all)

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