A Photocaged Microtubule-Stabilising Epothilone Allows Spatiotemporal Control of Cytoskeletal Dynamics.

The cytoskeleton is essential for spatial and temporal organisation of a wide range of cellular and tissue-level processes, such as proliferation, signalling, cargo transport, migration, morphogenesis, and neuronal development. Cytoskeleton research aims to study these processes by imaging, or by locally manipulating, the dynamics and organisation of cytoskeletal proteins with high spatiotemporal resolution: which matches the capabilities of optical methods. To date, no photoresponsive microtubule-stabilising tool has united all the features needed for a practical high-precision reagent: a low potency and biochemically stable non-illuminated state; then an efficient, rapid, and clean photoresponse that generates a high potency illuminated state; plus good solubility at suitable working concentrations; and efficient synthetic access. We now present CouEpo, a photocaged epothilone microtubule-stabilising reagent that combines these needs. Its potency increases approximately 100-fold upon violet/blue irradiation to reach low-nanomolar values, allowing efficient photocontrol of microtubule dynamics in live cells, and even the generation of cellular asymmetries in microtubule architecture and cell dynamics. CouEpo is thus a high-performance tool compound that can support high-precision research into many microtubule-associated processes, from biophysics to transport, cell motility, and neuronal physiology.

Melt Castable Derivatives of Pentaerythritol Tetranitrate.

In the search for high-performance and environmentally friendly energetic materials, the derivatization of known materials is an often-applied concept to fulfill modern-day demands. Surprisingly, the long know pentaerythritol tetranitrate (PETN) has only been derivatized to a limited extent. PETN shows a brought application in energetic materials or pharmaceutics. In this work, the PETN backbone is modified by introducing nitramine, ionic nitramine, amine, ionic amine and tetrazole functionalities. The obtained and structurally similar compounds allow good comparability and insights into functional group effects on sensitivity, thermal behavior and performance. The functionalizations result in melting points in the range of 64 to 126 °C. Some compounds are therefore potential candidates to replace toxic TNT.