Suchergebnisse

Enzymes can perform complex multistep cascade reactions by linking multiple distinct catalytic sites via substrate channeling. We mimic this feature in a generalized approach with an electrocatalytic nanoparticle for the carbon dioxide reduction reaction comprising a Ag core surrounded by a porous Cu shell, providing different active sites in nanoconfined volumes. The architecture of the nanozyme provides the basis for a cascade reaction, which promotes C−C coupling reactions. The first step occurs on the Ag core, and the subsequent steps on the porous copper shell, where a sufficiently high CO concentration due to the nanoconfinement facilitates C−C bond formation. The architecture yields the formation of n-propanol and propionaldehyde at potentials as low as −0.6 V vs RHE. ; W.S. is grateful for financial support by the Deutsche Forschungsgemeinschaft (EXC-2033-390677874) and the European Research Council (ERC) under the European Union's Horizon 2020 Research and Innovation Programme (grant agreement no. 833408). This work was supported by the DAAD in the framework of the PPP project 57446293 as well as the Ruhr University Research school PLUS through a research stay of P.W. at UNSW, funded by Germany's Excellence Initiative (DFG GSC 98/3). This research was financially supported by the Australian Research Council of Centre of Excellence in Convergent Bio-Nano Science and Technology (CE140100036), the ARC Australian Laureate Fellowship (FL150100060), the Discovery Project (DP190102659), and the Mark Wainwright Analytical Centre (MWAC) at UNSW. This work used the facilities supported by Microscopy Australia at the Electron Microscope Unit at UNSW. The authors are grateful to Dr. Douglas Lawes for discussion and assistance with 1H NMR experiments. P.B.O'M. acknowledges the Australian Government Research Training Program Scholarship for financial support. P.W. is grateful to the Association of the Chemical Industry e.V. (VCI) for funding of the Ph.D. fellowship.

Phytoplankton-bacteria interactions drive the surface ocean sulfur cycle and local climatic processes through the production and exchange of a key compound: dimethylsulfoniopropionate (DMSP). Despite their large-scale implications, these interactions remain unquantified at the cellular-scale. Here we use secondary-ion mass spectrometry to provide the first visualization of DMSP at sub-cellular levels, tracking the fate of a stable sulfur isotope (34S) from its incorporation by microalgae as inorganic sulfate to its biosynthesis and exudation as DMSP, and finally its uptake and degradation by bacteria. Our results identify for the first time the storage locations of DMSP in microalgae, with high enrichments present in vacuoles, cytoplasm and chloroplasts. In addition, we quantify DMSP incorporation at the single-cell level, with DMSP-degrading bacteria containing seven times more 34S than the control strain. This study provides an unprecedented methodology to label, retain, and image small diffusible molecules, which can be transposable to other symbiotic systems. ; This work was supported by ANNiMS (Australian Government, Department of Education, Employment and Workplace Relations), the AMMRF Centre for Microscopy, Characterisation and Analysis (UWA) and by Australian Research Council Grant DE160100636.