Physiological Significance of the Heterogeneous Distribution of Zeaxanthin and Lutein in the Retina of the Human Eye.

Zeaxanthin and lutein are xanthophyll pigments present in the human retina and particularly concentrated in its center referred to as the yellow spot (macula lutea). The fact that zeaxanthin, including its isomer -zeaxanthin, is concentrated in the central part of the retina, in contrast to lutein also present in the peripheral regions, raises questions about the possible physiological significance of such a heterogeneous distribution of macular xanthophylls. Here, we attempt to address this problem using resonance Raman spectroscopy and confocal imaging, with different laser lines selected to effectively distinguish the spectral contribution of lutein and zeaxanthin.

Benzophosphol-3-yl Triflates as Precursors of 1,3-Diarylbenzophosphole Oxides.

A simple method for the synthesis of 3-arylbenzophosphole oxides under Suzuki-Miyaura coupling conditions has been presented. It employs benzophosphol-3-yl triflate starting materials which, prior to our work, had not been used for the synthesis of 3-arylbenzophosphole oxides. The reactions proceed over 24 h and provide a library of 3-arylbenzophosphole oxides.

The photoprotective dilemma of a chloroplast: to avoid high light or to quench the fire?

The safe and smooth functioning of photosynthesis in plants is ensured by the operation of numerous regulatory mechanisms that adjust the density of excitation resulting from photon absorption to the capabilities of the photosynthetic apparatus. Such mechanisms include the movement of chloroplasts inside cells and the quenching of electronic excitations in the pigment-protein complexes. Here, we address the problem of a possible cause-and-effect relationship between these two mechanisms.

Mechanisms shaping the synergism of zeaxanthin and PsbS in photoprotective energy dissipation in the photosynthetic apparatus of plants.

Safe operation of photosynthesis is vital to plants and is ensured by the activity of processes protecting chloroplasts against photo-damage. The harmless dissipation of excess excitation energy is considered to be the primary photoprotective mechanism and is most effective in the combined presence of PsbS protein and zeaxanthin, a xanthophyll accumulated in strong light as a result of the xanthophyll cycle. Here we address the problem of specific molecular mechanisms underlying the synergistic effect of zeaxanthin and PsbS.