Abstract
Cultured cell line (GTH4) of F1 hybrid between Nicotoana gossei Domin and N.tabacum L. grows normally at 37C, while dies at 26C. Quick loss of viability at 26C within 6 h was followed by slow cell death, resulting biphasic pattern, and eventually about 20% of cells were still alive at 72 h. Cell death was suppressed under anaerobic condition, suggesting involvement of superoxide intermediate (ROI) reduced from oxygen. The burst of O2- and H2O2 in the cell was detected as the peaks at 2 h and 0.5 h after transfer to 26C, respectively, while no increase at 37C. The burst of H2O2 was very low in the cell under anaerobic condition, but amount of O2- gradually increased in high level at later stage. Other findings and the results of pharmacological experiments including inhibitors of NADPH oxidase indicated that H2O2 was very probably involved in cell death process.
