Sub-100-fs energy transfer in coenzyme NADH is a coherent process assisted by a charge-transfer state.

Excitation energy transfer (EET) is a key photoinduced process in biological chromophoric assemblies. Here we investigate the factors which can drive EET into efficient ultrafast sub-ps regimes. We demonstrate how a coherent transport of electronic population could facilitate this in water solvated NADH coenzyme and uncover the role of an intermediate dark charge-transfer state. High temporal resolution ultrafast optical spectroscopy gives a 54±11 fs time constant for the EET process. Nonadiabatic quantum dynamical simulations computed through the time-evolution of multidimensional wavepackets suggest that the population transfer is mediated by photoexcited molecular vibrations due to strong coupling between the electronic states. The polar aqueous solvent environment leads to the active participation of a dark charge transfer state, accelerating the vibronically coherent EET process in favorably stacked conformers and solvent cavities. Our work demonstrates how the interplay of structural and environmental factors leads to diverse pathways for the EET process in flexible heterodimers and provides general insights relevant for coherent EET processes in stacked multichromophoric aggregates like DNA strands.

A Proposed Serum Calprotectin IgG Cut-Off Level for Diagnosing Inflammatory Arthritis.

BACKGROUND: The identification and validation of soluble markers provide significant opportunities for managing patients with rheumatic diseases, and calprotectin may be an alternative laboratory biomarker of inflammatory rheumatoid arthritis (RA) and psoriatic arthritis (PsA) even though its levels may vary considerably. The aim of this study was to propose a calprotectin cut-off value that would be useful for distinguishing patients with inflammatory arthritis or noninflammatory arthritis (NIA) in clinical practice. METHODS: A commercial enzyme-linked immunosorbent assay was used to measure serum calprotectin levels in patients with RA, ankylosing spondylitis (AS), PsA and controls with NIA. All of the patients had been treated with biological disease-modifying anti-rheumatic drugs (DMARDs) for about 12 months after previous failure on conventional DMARDs. RESULTS: Receiver operating characteristic (ROC) analysis showed that serum calprotectin levels significantly differentiated the samples of the patients with inflammatory rheumatic disease from those of the controls. A serum calprotectin level of > 0.9 µg/mL (the optimal predictive cut-off value in the ROC analysis) had a sensitivity of 95.3%, a specificity of 82.2%, a positive likelihood ratio (LR) of 5.35 and a negative LR of 0.057. CONCLUSIONS: Our findings suggest that serum calprotectin levels are useful in clinical practice to distinguish patients with inflammatory arthritis and NIA. Further studies of a larger population are suggested.

Selective fitness of four episomal shuttle-vectors carrying HIS3, LEU2, TRP1, and URA3 selectable markers in Saccharomyces cerevisiae.

A comparison of the selective fitness of four 2-microm-based shuttle-plasmids carrying the yeast genes HIS3, LEU2, TRP1, and URA3 was performed. The effect of each marker on long-term growth rate and plasmid maintenance was measured. In selective medium, the LEU2 and URA3 plasmids were maintained at the lowest and the highest levels, respectively, while the HIS3 and TRP1 plasmids were maintained at an intermediate level. In synthetic complete medium, plasmid loss rate was lower for the genes TRP1 and URA3 than for the other two markers, and a similar pattern was observed for cells growing in rich medium. These results were confirmed by competition experiments among transformants with different plasmids in complete and rich media, indicating a different degree of fitness for the markers used. A potential correlation of the energy cost of plasmid maintenance with the secondary DNA structure and the level of expression of the selective markers is also investigated.