76 research outputs found
Observation of the solid-state photo-CIDNP effect in entire cells of cyanobacteria Synechocystis
Cyanobacteria are widely used as model organism of oxygenic photosynthesis due to being the simplest photosynthetic organisms containing both photosystem I and II (PSI and PSII). Photochemically induced dynamic nuclear polarization (photo-CIDNP) 13C magic-angle spinning (MAS) NMR is a powerful tool in understanding the photosynthesis machinery down to atomic level. Combined with selective isotope enrichment this technique has now opened the door to study primary charge separation in whole living cells. Here, we present the first photo-CIDNP observed in whole cells of the cyanobacterium Synechocystis
The solid-state photo-CIDNP effect
The solid-state photo-CIDNP effect is the occurrence of a non-Boltzmann nuclear spin polarization in rigid samples upon illumination. For solid-state NMR, which can detect this enhanced nuclear polarization as a strong modification of signal intensity, the effect allows for new classes of experiments. Currently, the photo- and spin-chemical machinery of various RCs is studied by photo-CIDNP MAS NMR in detail. Until now, the effect has only been observed at high magnetic fields with 13C and 15N MAS NMR and in natural photosynthetic RC preparations in which blocking of the acceptor leads to cyclic electron transfer. In terms of irreversible thermodynamics, the high-order spin structure of the initial radical pair can be considered as a transient order phenomenon emerging under non-equilibrium conditions and as a first manifestation of order in the photosynthetic process. The solid-state photo-CIDNP effect appears to be an intrinsic property of natural RCs. The conditions of its occurrence seem to be conserved in evolution. The effect may be based on the same fundamental principles as the highly optimized electron transfer. Hence, the effect may allow for guiding artificial photosynthesis
Plant acquisition and metabolism of the synthetic nitrification inhibitor dicyandiamide and naturally-occurring guanidine from agricultural soils
Soil organic matter dynamics: a biological perspective derived from the use of compound-specific isotopes studies
Characterization of asphaltenes by pyrolysis-field ionization mass spectrometry—some observations
Direkte Isotopenbestimmung von isotopenmarkierten Lipiden mit Hilfe der Felddesorptions-Massenspektrometrie
Analyse von Natrium-alkylsulfonaten durch Elektronenstoß-Massenspektrometrie mit Probenerhitzung im Elektronenstrahl
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