Inhibition of cathepsin B by caspase-3 inhibitors blocks programmed cell death in <i>Arabidopsis</i>

Programmed cell death (PCD) is used by plants for development and survival to biotic and abiotic stresses. The role of caspases in PCD is well established in animal cells. Over the past 15 years, the importance of caspase-3-like enzymatic activity for plant PCD completion has been widely documented despite the absence of caspase orthologues. In particular, caspase-3 inhibitors blocked nearly all plant PCD tested. Here, we affinity-purified a plant caspase-3-like activity using a biotin-labelled caspase-3 inhibitor and identified Arabidopsis thaliana cathepsin B3 (AtCathB3) by liquid chromatography with tandem mass spectrometry (LC-MS/MS). Consistent with this, recombinant AtCathB3 was found to have caspase-3-like activity and to be inhibited by caspase-3 inhibitors. AtCathepsin B triple-mutant lines showed reduced caspase-3-like enzymatic activity and reduced labelling with activity-based caspase-3 probes. Importantly, AtCathepsin B triple mutants showed a strong reduction in the PCD induced by ultraviolet (UV), oxidative stress (H2O2, methyl viologen) or endoplasmic reticulum stress. Our observations contribute to explain why caspase-3 inhibitors inhibit plant PCD and provide new tools to further plant PCD research. The fact that cathepsin B does regulate PCD in both animal and plant cells suggests that this protease may be part of an ancestral PCD pathway pre-existing the plant/animal divergence that needs further characterisation

Nucleophile Addition von Carbonylmetallaten an metallkoordinierte #pi#-Synthese - gezielte Synthese kohlenwasserstoffverbrueckter Mehrkernkomplexe

Available from TIB Hannover: DW 2247 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Flipped Classroom Implementation: A Case Report of Two Higher Education Institutions in the United States and Australia

This case report explored the implementation of flipped classrooms at two higher education institutions. Experiences and publications from the institutions were used to identify and describe common themes, including successes and challenges encountered along with potential solutions to common misalignments, particularly as related to technology-enhanced learning. Strategies for selecting and delivering pre-class content, designing and implementing in-class activities, and identifying and using assessments to inform practice are described. Overall design considerations include instructor skill development, student buy-in, and institutional support for the model. This report highlights several critical approaches to effectively designing and implementing the flipped classroom model, with consideration given to the use of technology to support this innovation