TOR (target of rapamycin) signaling regulates life span in many organisms, but the mechanism behind the effect is unknown. In this issue of Cell Metabolism, Pan and colleagues (2011) find that reduced TORC1 activity promotes yeast life span via a mechanism that, paradoxically, relies upon the production of normally deleterious reactive oxygen species.

A comprehensive understanding of ROS (reactive oxygen species)-dependent cellular interaction requires the previously unmet ability to simultaneously monitor the intra- and extra-cellular environments. The present review assesses the potential of novel electrochemical and fluorescent-based nanosensor approaches to address the limitations of existing techniques for ROS analysis. Data generated b...

The fluorescence intensity and lifetime of the 4,4'-difluoro-4-bora-5-(p-oxoalkyl)phenyl-3a,4a-diaza-s-indacene (1) show a strong correlation with the viscosity of the medium due to the viscosity-dependent twisting of the 5-phenyl group, which gives access to the dark nonemissive excited state. We propose a sensitive and versatile method for measuring the local microviscosity in biological syst...

2009 2 CONTENTS 1. INTRODUCTION 9 1.1. Free radicals and their derivatives in living organisms 9 1.1.1. Reactive oxygen species (ROS) 11 1.1.2. Reactive nitrogen species (RNS) 13 1.1.3. Protective mechanisms against free radicals.