Marine Biology

, Volume 156, Issue 11, pp 2209–2220

Implication of nitric oxide in the heat-stress-induced cell death of the symbiotic alga Symbiodinium microadriaticum

Original Paper

DOI: 10.1007/s00227-009-1249-3

Cite this article as:
Bouchard, J.N. & Yamasaki, H. Mar Biol (2009) 156: 2209. doi:10.1007/s00227-009-1249-3

Abstract

One of the major consequences of global warming is a rise in sea surface temperature which may affect the survival of marine organisms including phytoplankton. Here, we provide experimental evidence for heat-induced cell death in a symbiotic microalga. Shifting Symbiodinium microadriaticum from 27 to 32°C resulted in an increase in mortality, an increase in caspase 3-like activity, and an increase in nitric oxide (NO) production. The caspase-like activity was strongly correlated with the production of NO in thermally challenged microalgae. For this experiment, the application of Ac-DEVD-CHO, a mammalian caspase 3-specific inhibitor, partly prevented (by 65%) the increase in caspase-like activity. To verify the relationship between NO and the caspase-like activity, S. microadriaticum were subsequently incubated with 1.0 mM of the following chemical NO donors: sodium nitroprusside (SNP), S-nitrosoglutathione (GSNO), S-nitroso-N-acetylpenicillamine (SNAP) and 3,3bis(Aminoethyl)-1-hydroxy-2-oxo-1-triazene (NOC-18). The supplementation of both SNP and NOC-18 caused a significant increase in caspase-like activity compared to the control treatment. Pre-treatment of the microalgae with the inhibitor Ac-DEVD-CHO before the supplementation of the different NO donors completely prevented the increase in caspase-like activity. These results suggest that NO could play a role in the induction of cell death in heat-stressed S. microadriaticum by mediating an increase in caspase-like activity.

Abbreviations

H2O2

Hydrogen peroxide

NO

Nitric oxide

O2

Superoxide

ONOO

Peroxinitrite

PCD

Programmed cell death

ROIs

Reactive oxygen intermediates

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Faculty of ScienceUniversity of the RyukyusNishiharaJapan
  2. 2.National Oceanography CentreUniversity of SouthamptonSouthamptonUK

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