Ribonucleotide reductase regulation in response to genotoxic stress in Arabidopsis.

Ribonucleotide reductase (RNR) is an essential enzyme that provides dNTPs for DNA replication and repair. Arabidopsis (Arabidopsis thaliana) encodes three AtRNR2-like catalytic subunit genes (AtTSO2, AtRNR2A, and AtRNR2B). However, it is currently unclear what role, if any, each gene contributes to the DNA damage response, and in particular how each gene is transcriptionally regulated in response to replication blocks and DNA damage.

Copper(I) zeolites as heterogeneous and ligand-free catalysts: [3+2] cycloaddition of azomethine imines.

Copper(I)-exchanged zeolites were used as heterogeneous ligand-free catalysts for [3+2] cycloaddition of azomethine ylides, which allows versatile, efficient, and highly regioselective synthesis of pyrazolone derivatives. These cheap and easy-to-prepare catalysts exhibit wide scope and compatibility with functional groups. They are very simple to use, easy to remove (by simple filtration), and recyclable (up to six times without loss of activity).