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The orange carotenoid protein (OCP) is a structurally and functionally modular photoactive protein involved in cyanobacterial photoprotection. Recently, based on bioinformatic analysis and phylogenetic relationships, new families of OCP have been described, OCP2 and OCPx. The first characterization of the OCP2 showed both faster photoconversion and back-conversion, and lower fluorescence quenching of phycobilisomes relative to the well-characterized OCP1. Moreover, OCP2 is not regulated by the fluorescence recovery protein (FRP). In this work, we present a comprehensive study combining ultrafast spectroscopy and structural analysis to compare the photoactivation mechanisms of OCP1 and OCP2 from Tolypothrix PCC 7601. We show that despite significant differences in their functional characteristics, the spectroscopic properties of OCP1 and OCP2 are comparable. This indicates that the OCP functionality is not directly related to the spectroscopic properties of the bound carotenoid. In addition, the structural analysis by X-ray footprinting reveals that, overall, OCP1 and OCP2 have grossly the same photoactivation mechanism. However, the OCP2 is less reactive to radiolytic labeling, suggesting that the protein is less flexible than OCP1. This observation could explain fast photoconversion of OCP2.

In radon balneotherapy, in some cases, the natural source activity for a stronger treatment may be inadequate low. Therefore, a field experiment was made to produce a highly active preparation, by extracting radon from water into olive oil, on a technical scale.The spring of Bretislav (*2016) was used as a source of radon water (http://www.estudanky.eu/11000-radonka-pramen-bretislav). Its actual parameters were: Activity 12123 Bq/L of Rn-222, flow rate 2.8 L/min, temperature 8.0 °C.Extraction was carried out in a "2 L" glass separating funnel. 2 liters of fresh water were always used. The starting amount was 120 ml of food-grade, non-virgin olive oil. The 165 ml bubble was left in the funnel to facilitate the mixing of the phases. A time snap was also taken from the all off extraction steps. After shaking (1 min), the phases were separated (2-4 min) and the water was poured, the gamma activity of the oil in the funnel was measured by sensitive scintilometer and a 1 ml sample was taken for later LSC determination of Rn on a field basis. Gradually, 9 subsequent extractions were performed over a total time of 1 h 27 min. 76 ml of oil with an activity of 130 kBq/L of Rn-222 was obtained finally. Gama activity grew gradually, with an equilibrium level of 84 % after the ninth extraction. On the other hand, oil is saturated about 100% already in the third extraction; in a total time of 23 min. Radon oil was used by the author's team for healing purposes in the evening. [ABSTRACT FROM AUTHOR]