caa a22 4500 445890851 CHVBK 20180317145615.0 cr unu---uuuuu 170323e20110601xx s 000 0 eng 10.1007/s10750-011-0642-3 doi (NATIONALLICENCE)springer-10.1007/s10750-011-0642-3 A novel growth-promoting protein in the conditioned media from the rotifer Brachionus plicatilis at an early exponential growth phase [Elektronische Daten] [Fumito Ohmori, Gen Kaneko, Toshio Saito, Shugo Watabe] We confirmed the existence of growth-promoting substances in the conditioned media (CM) from the rotifer Brachionus plicatilis at an early exponential growth phase and isolated a novel protein with a growth-promoting activity from the crude extract (CE) of rotifer cells. CM was prepared from the culture media where rotifers had been cultured at an early exponential growth phase and filtered through a 0.22-μm filter membrane. The growth-promoting activity was determined using rotifers in CM for 5days. As a result, the increase of rotifers added with CM was significantly higher than that of the control in artificial seawater (P<0.001). Moreover, the growth-promoting activity of CM was dose-dependent and inactivated by heat treatment at 80°C for 60min. Meanwhile, CM filtered through a <10kDa ultrafiltration membrane showed a low activity, whereas proteinase K treatment resulted in a complete inactivation. These results suggest that the rotifer secrets growth-promoting proteins into CM. CE also contained a protein with the activity and properties similar to those found in CM. Then, CE was subjected to purification of a growth-promoting protein for convenience using various types of chromatography after fractionation with 30-80% saturated ammonium sulfate. Subsequently, a protein with an approximate molecular weight of 25000 was isolated, and its N-terminal amino acid sequence was determined to be PAVVDFTAVWFGPLQMIKP. An orthologue was found in the EST database of B. plicatilis, the full sequence of which showed about 50% identity to the corresponding regions of thioredoxins from other organisms. Springer Science+Business Media B.V., 2011 Brachionus plicatilis nationallicence Conditioned media nationallicence Early exponential phase nationallicence Growth-promoting substance nationallicence Rotifer nationallicence Thioredoxin nationallicence Ohmori Fumito Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 113-8657, Bunkyo, Tokyo, Japan aut Kaneko Gen Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 113-8657, Bunkyo, Tokyo, Japan aut Saito Toshio Department of Marine Biology, School of Marine Science and Technology, Tokai University, 424-8610, Shimizu, Shizuoka, Japan aut Watabe Shugo Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 113-8657, Bunkyo, Tokyo, Japan aut Hydrobiologia Springer Netherlands 667/1(2011-06-01), 101-117 0018-8158 667:1<101 2011 667 10750 https://doi.org/10.1007/s10750-011-0642-3 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10750-011-0642-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ohmori Fumito Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 113-8657, Bunkyo, Tokyo, Japan aut NATIONALLICENCE 700 1- Kaneko Gen Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 113-8657, Bunkyo, Tokyo, Japan aut NATIONALLICENCE 700 1- Saito Toshio Department of Marine Biology, School of Marine Science and Technology, Tokai University, 424-8610, Shimizu, Shizuoka, Japan aut NATIONALLICENCE 700 1- Watabe Shugo Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 113-8657, Bunkyo, Tokyo, Japan aut NATIONALLICENCE 773 0- Hydrobiologia Springer Netherlands 667/1(2011-06-01), 101-117 0018-8158 667:1<101 2011 667 10750 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer