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Megafauna are important seed dispersers because they can disperse large quantities of seeds over long distances. In Hokkaido, Japan, the largest terrestrial animal is the brown bear (Ursus arctos) and other megafauna seed dispersers are lacking. Thus, brown bears are expected to have an important function as seed dispersers in Hokkaido. In this study, we, for the first time, evaluated the seed dispersal function of brown bears in Hokkaido using three fleshy-fruited trees and studied: (1) gut passage time (GPT) in feeding experiments, (2) seed dispersal distance using tracking data of wild bears, and (3) the effect of gut passage and pulp removal on germination rate. Most seeds were defecated intact, and less than 6% were broken. The average GPT without pulp was 3 h and 56 min to 6 h and 13 min, depending on the plant and trial. Each plant's average simulated seed dispersal distance was 202–512 m. The dispersal distance of Actinidia arguta seeds with pulp was significantly longer than those without pulp because of their longer GPT. The germination rate of defecated seeds without pulp was 19–51%, depending on the plant, and was significantly higher or not different comparing with that of seeds with pulp. We concluded that brown bears in Hokkaido are effective seed dispersers. In managing brown bears in Hokkaido, such ecological functions should be considered along with conserving the bear population and reducing human–bear conflicts. [ABSTRACT FROM AUTHOR]

Two East Asian grape species Vitis amurensis and Vitis coignetiae have been investigated for their increased cold and drought tolerance and high level of resistance to infections. Nowadays, the grape species attract attention due to their capability to produce a group of valuable plant secondary metabolites named stilbenes. The basic stilbene, t-resveratrol, is known to demonstrate a high bioactivity and is synthesized by stilbene synthase (STS) in grape cells. In order to find the suitable biological model for t-resveratrol production, 12 cell culture lines derived from the leaf, petiole and stem explants of the East Asian grape species were tested for their ability to produce t-resveratrol and other stilbenes. The comparative analysis showed that the V. coignetiae cell culture lines were the most productive in terms of stilbene content. This observation was confirmed by the increased level of STS expression in V. coignetiae cells in comparison to V. amurensis. The expression analysis of the genes encoding transcription factors potentially involved in regulation of STS genes revealed the significant species-specific differences, suggesting the molecular basis underlying the observed differences in stilbene biosynthetic potential of V. amurensis and V. coignetiae. Key message: The comparative analysis revealed the greater stilbene production potential for cells of V. coignetiae due to enhanced STS expression determinated by Myb1/15, Myb40 and Myb60 transcription factors. [ABSTRACT FROM AUTHOR]

The methanol extract of the Oriental medicinal plant Vitis coignetiae (Vitaceae) showed hepatoprotective activity in the in vitro assay method using primary cultured rat hepatocytes. Activity-guided fractionation of the extract afforded ɛ-viniferin as an active principle. The protective effect of ɛ-viniferin against mice carbon tetrachloride-induced hepatic injury in mice was shown by serum enzyme assay as well as by pathological examination. In addition to ɛ-viniferin, plant oligostilbenes, ampelopsins A, C, F and the mixture of vitisin A and cis-vitisin A were also present in the extract. Among them, ampelopsin C and the mixture of vitisin A and cis-vitisin A were found to be powerful hepatotoxins. [ABSTRACT FROM AUTHOR]