Chapter 34: Singlet Oxygen in Mammalian Cells

It is acknowledged that singlet oxygen can play a variety of important roles in mammalian cells, resulting in cell responses that range from proliferation to death. It is certain that many of these cell responses reflect roles that singlet oxygen plays in signaling mechanisms. Although the behavior of singlet oxygen in cells, and the associated responses of cells, has been studied for decades, the past ∼10 years have seen some dramatic changes in the field. Many of these changes reflect the development and application of new tools that provide unique information and mechanistic insight. Of particular relevance has been the ability to directly detect singlet oxygen via its 1275 nm phosphorescence in photosensitized time-resolved microscope-based single-cell experiments. An overview of selected information available from such experiments is presented in this chapter.