Selenoprotein S (SelS) is widely expressed in diverse tissues where it localizes in the plasma membrane and endoplasmic reticulum. We studied the potential function of SelS in erythrocyte differentiation using K562 cells stably over-expressing SelS wild-type (WT) or one of two SelS point mutants, U188S or U188C. We found that in the K562 cells treated with 1μM Ara-C, SelS gradually declined over five days of treatment. On day 4, intracellular ROS levels were higher in cells expressing SelS-WT than in those expressing a SelS mutant. Moreover, the cell cycle patterns in cells expressing SelS-WT or U188C were similar to the controls. The expression and activation of SIRT1 were also reduced during K562 differentiation. Cells expressing SelS-WT showed elevated SIRT1 expression and activation (phosphorylation), as well as higher levels of FoxO3a expression. SIRT1 activation was diminished slightly in cells expressing SelS-WT after treatment with the ROS scavenger NAC (12 mM), but not in those expressing a SelS mutant. After four days of Ara-C treatment, SelS-WT-expressing cells showed elevated transcription of β-globin, y-globin, ε-globin, GATA-1 and zfpm-1, whereas cells expressing a SelS mutant did not. These results suggest that the suppression of SelS acts as a trigger for proerythrocyte differentiation via the ROS-mediated downregulation of SIRT1.

This study selected commonly known species of fruit trees, and re-selected the species that endure the stress of extreme cold weather and physiologically restore themselves to the previous state until the following year. Then we could go ahead to propose the species that were appropriate as urban greening plants in weather condition of any part of the country. To do this, we conducted an experiments for six species of fruit trees based on the preference of the general public and recommendation of the experts; Morus alba (English name: mulberries), Diospyros kaki (English name: Persimmon), Prunus persia (English name: Peach), Elaeagnus umbellata var. coreana (English name: Korean Autumn Olive), Malus domestica 'Alps Otome' (English name: Alps Otome), and Prunus mume (English name: Blue Plum). The experiment verifies whether the trees survive without any stress from the cold weather under the national climate conditions (one in the suburbs of Seoul: Yongin city, one in the central Chungcheong region: Daejeon city, and in the southern Gyeongsang region: Jinju city in Korea). The experiment lasted for a year from August 2016 to August 2017. The levels of electrolytic efflux, chlorophyll content, plant height, fresh weight, and dry weight were measured four times (on August of 2016, January, February, and August of 2017) for each tree planted bare ground outdoors. Results showed that Diospyros kaki, Prunus persia, and Malus domestica 'Alps Otome' were proven durable and resistant to winters of all three areas (one in the suburbs of Seoul: Yongin city, one in the central Chungcheong region: Daejeon city, and in the southern Gyeongsang region: Jinju city in Korea). Especially, the increase of chlorophyll content and the reduction of electrolytic efflux were noticeable in Prunus persia than in the other two species, proving itself as the most cold-tolerant among the six species used in the experiment. In addition, interpreting from the physiological restoration data of one-year span before and after getting through winterer, Prunus persia was proven to be the most cold-tolerant species.