The chemical compound 'Heatin' stimulates hypocotyl elongation and interferes with the Arabidopsis NIT1-subfamily of nitrilases

Temperature passively affects biological processes involved in plant growth. Therefore, it is challenging to study the dedicated temperature signalling pathways that orchestrate thermomorphogenesis, a suite of elongation growth-based adaptations that enhance leaf-cooling capacity. We screened a chemical library for compounds that restored hypocotyl elongation in the pif4-2-deficient mutant background at warm temperature conditions in Arabidopsis thaliana to identify modulators of thermomorphogenesis. The small aromatic compound 'Heatin', containing 1-iminomethyl-2-naphthol as a pharmacophore, was selected as an enhancer of elongation growth. We show that ARABIDOPSIS ALDEHYDE OXIDASES redundantly contribute to Heatin-mediated hypocotyl elongation. Following a chemical proteomics approach, the members of the NITRILASE1-subfamily of auxin biosynthesis enzymes were identified among the molecular targets of Heatin. Our data reveal that nitrilases are involved in promotion of hypocotyl elongation in response to high temperature and Heatin-mediated hypocotyl elongation requires the NITRILASE1-subfamily members, NIT1 and NIT2. Heatin inhibits NIT1-subfamily enzymatic activity in vitro and the application of Heatin accordingly results in the accumulation of NIT1-subfamily substrate indole-3-acetonitrile in vivo. However, levels of the NIT1-subfamily product, bioactive auxin (indole-3-acetic acid), were also significantly increased. It is likely that the stimulation of hypocotyl elongation by Heatin might be independent of its observed interaction with NITRILASE1-subfamily members. However, nitrilases may contribute to the Heatin response by stimulating indole-3-acetic acid biosynthesis in an indirect way. Heatin and its functional analogues present novel chemical entities for studying auxin biology

Methanol reforming by nanostructured Pd/Sm-doped ceria catalysts

Catalysts of 2 wt% Pd/Sm-doped Ceria (SDC) were prepared and evaluated for hydrogen production by methanol reforming. Three preparation methods were used: a one-step method in which formation of the SDC phase and Pd incorporation took place in a single citrate-complexation process (Method A); impregnation of pre-prepared SDC nanopowder supports using Pd(NO3)2 solution (Method B); and impregnation of pre-prepared SDC from H2PdCl4 solution (Method C). Both methanol conversion and hydrogen yield increased as: bare supports<<Method A < Method C < Method B, the latter achieving values of up to 97.4 % and 236.2 %, respectively. Pd was well dispersed as fine nanoparticles by Methods B and C, but larger particles were resolved for Method A. Method B resulted in a high surface concentration of Pd, further improving catalytic activity. Undesirable Cl was retained in samples of Method C. Method B resulted in catalysts with superior nanostructure, resulting in the best activity and CO2 selectivity