15N Photo-CIDNP MAS NMR To Reveal Functional Heterogeneity in Electron Donor of Different Plant Organisms

In plants and cyanobacteria, two light-driven electron pumps, photosystems I and II (PSI, PSII), facilitate electron transfer from water to carbon dioxide with quantum efficiency close to unity. While similar in structure and function, the reaction centers of PSI and PSII operate at widely different potentials with PSI being the strongest reducing agent known in living nature. Photochemically induced dynamic nuclear polarization (photo-CIDNP) in magic-angle spinning (MAS) nuclear magnetic resonance (NMR) measurements provides direct excess to the heart of large photosynthetic complexes (A. Diller, Alia, E. Roy, P. Gast, H.J. van Gorkom, J. Zaanen, H.J.M. de Groot, C. Glaubitz, J. Matysik, Photosynth. Res. 84, 303–308, 2005; Alia, E. Roy, P. Gast, H.J. van Gorkom, H.J.M. de Groot, G. Jeschke, J. Matysik, J. Am. Chem. Soc. 126, 12819–12826, 2004). By combining the dramatic signal increase obtained from the solid-state photo-CIDNP effect with 15N isotope labeling of PSI, we were able to map the electron spin density in the active cofactors of PSI and study primary charge separation at atomic level. We compare data obtained from two different PSI proteins, one from spinach (Spinacia oleracea) and other from the aquatic plant duckweed (Spirodella oligorrhiza). Results demonstrate a large flexibility of the PSI in terms of its electronic architecture while their electronic ground states are strictly conserved

Solid-state NMR of nanomachines involved in photosynthetic energy conversion

Solid state NMR/Biophysical Organic Chemistr

The solid-state photo-CIDNP effect

Solid state NMR/Biophysical Organic Chemistr

Historical Overview of the Human Population-Genetic Studies in Bosnia and Herzegovina: Small Country, Great Diversity

Modern Bosnia and Herzegovina is a multinational and multi-religious country, situated in the western part of the Balkan Peninsula in South-eastern Europe. According to recent archaeological findings, Bosnia and Herzegovina has been occupied by modern humans since the Palaeolithic period. The structure of Bosnia-Herzegovina’s human populations is very complex and specific, due to which it is interesting for various population-genetic surveys. The population of Bosnia and Herzegovina has been the focus of bio-anthropological and population genetics studies since the 19th century. The first known bio-anthropological analyses of Bosnia-Herzegovina population were primarily based on the observation of some phenotypic traits. Later examinations included cytogenetic and DNA based molecular markers. The results of all studies which have been done up to date showed no accented genetic difference among the populations (based on geographical regions) with quite high diversity within them. Human population of Bosnia and Herzegovina is closely related to other populations in the Balkans. However, there are still many interesting features hidden within the existing diversity of local human populations that are still waiting to be discovered and described

Analysis of electron donors in photosystems in oxygenic photosynthesis by photo-CIDNP MAS NMR

Solid state NMR/Biophysical Organic Chemistr

Symmetry break of special pair: photochemically induced dynamic nuclear polarization NMR confirms control by nonaromatic substituents

Solid state NMR/Biophysical Organic Chemistr

15N photo-CIDNP MAS NMR analysis of a bacterial photosynthetic reaction center of rhodobacter sphaeroides wildtype

Solid state NMR/Biophysical Organic Chemistr

An integrated systems-level model of ochratoxin A toxicity in the zebrafish (Danio rerio) embryo based on NMR metabolic profiling

Ochratoxin A (OTA) is one of the most widespread mycotoxin contaminants of agricultural crops. Despite being associated with a range of adverse health effects, a comprehensive systems-level mechanistic understanding of the toxicity of OTA remains elusive. In the present study, metabolic profiling by high-resolution magic angle spinning (HRMAS) NMR, coupled to intact zebrafish embryos, was employed to identify metabolic pathways in relation to a systems-level model of OTA toxicity. Embryotoxicity was observed at sub-micromolar exposure concentrations of OTA. Localization of OTA, based on intrinsic fluorescence, as well as a co-localization of increased reactive oxygen species production, was observed in the liver kidney, brain and intestine of embryos. Moreover, HRMAS NMR showed significant alteration of metabolites related to targeting of the liver (i.e., hepatotoxicity), and pathways associated with detoxification and oxidative stress, and mitochondrial energy metabolism. Based on metabolic profiles, and complementary assays, an integrated model of OTA toxicity is, thus, proposed. Our model suggests that OTA hepatotoxicity compromises detoxification and antioxidant pathways, leading to mitochondrial membrane dysfunction manifested by crosstalk between pathways of energy metabolism. Interestingly, our data additionally aligns with a possible role of mitochondrial fusion as a "passive mechanism" to rescue mitochondrial integrity during OTA toxicity.Solid state NMR/Biophysical Organic Chemistr

Signals in solid-state photochemically induced dynamic nuclear polarization recover faster than signals obtained with the longitudinal relaxation time

Biological and Soft Matter PhysicsSolid state NMR/Biophysical Organic Chemistr

Nanosecond-Flash N-15 Photo-CIDNP MAS NMR on reaction centers of Rhodobacter sphaeroides R26

Solid state NMR/Biophysical Organic ChemistryBiological and Soft Matter Physic