Berman-Frank, I. R.. Rutgers University, irfrank@imcs.rutgers.edu
Rosenberg, T. R.. Hebrew University of Jerusalem,
Vardi, A. Hebrew University of Jerusalem,
Hadas, O. Yigal Alon Kinneret Limnological Laboratory,
Kaplan, A. Hebrew University of Jerusalem,
Levine, . Hebrew University of Jerusalem,

 
CO2 LIMITATION INDUCES OXIDATIVE STRESS AND PROGRAMMED CELL DEATH IN THE DINOFLAGELLATE PERIDINIUM GATUNENSE
 
The dinoflagellate, Peridinium gatunense, which blooms annually during winter-spring and dominates the algal population in Lake Kinneret (Israel) terminates in a sudden collapse. Processes regulating the dinoflagellate demise are not known. Similar population decline was observed in batch cultures of P. gatunense grown under controlled conditions. We show that CO2 limitation that developed during growth led to the generation of reactive oxygen species (ROS). This decreased the photosynthetic capacity of the cells and stimulated the formation of additional ROS leading to the death of the cells. The degree of cell death following mild oxidative stress increased with population age. Young cultures could be conditioned to respond to oxidants by placing cells in a medium derived from older populations. Death in senescing cells could be prevented by the addition of ROS scavengers (catalase or by a ROS spin trap, 4-hydroxyTempo) or by a cysteine protease inhibitor,E-64. The process of cell death had some common features with programmed cell death of animal and plant cells as judged by a progressive shrinkage of the protoplast, a threshold response to H2O2, a time dependent cell death process and the involvement of cystein proteases in the process.
 
Day: Tuesday, Feb. 2
Time: Poster
Location: Sweeney Center
 
Code: SS41TU1580S