A pathway of neuregulin-induced activation of cofilin-phosphatase Slingshot and cofilin in lamellipodia

Cofilin mediates lamellipodium extension and polarized cell migration by stimulating actin filament dynamics at the leading edge of migrating cells. Cofilin is inactivated by phosphorylation at Ser-3 and reactivated by cofilin-phosphatase Slingshot-1L (SSH1L). Little is known of signaling mechanisms of cofilin activation and how this activation is spatially regulated. Here, we show that cofilin-phosphatase activity of SSH1L increases ∼10-fold by association with actin filaments, which indicates that actin assembly at the leading edge per se triggers local activation of SSH1L and thereby stimulates cofilin-mediated actin turnover in lamellipodia. We also provide evidence that 14-3-3 proteins inhibit SSH1L activity, dependent on the phosphorylation of Ser-937 and Ser-978 of SSH1L. Stimulation of cells with neuregulin-1β induced Ser-978 dephosphorylation, translocation of SSH1L onto F-actin–rich lamellipodia, and cofilin dephosphorylation. These findings suggest that SSH1L is locally activated by translocation to and association with F-actin in lamellipodia in response to neuregulin-1β and 14-3-3 proteins negatively regulate SSH1L activity by sequestering it in the cytoplasm

キナ植物体内に生息するエンドファイト糸状菌もキナアルカロイドを産生する(発表論文抄録(2011))

We report that the endophytic filamentous fungus Diaporthe sp., isolated from Cinchona ledgeriana and cultivated in a synthetic liquid medium, produces Cinchona alkaloids (quinine, quinidine, cinchonidine, and cinchonine). This shows that Cinchona alkaloids are produced not only in Cinchona plant cells, but also in endophytic microbe cells.We report that the endophytic filamentous fungus Diaporthe sp., isolated from Cinchona ledgeriana and cultivated in a synthetic liquid medium, produces Cinchona alkaloids (quinine, quinidine, cinchonidine, and cinchonine). This shows that Cinchona alkaloids are produced not only in Cinchona plant cells, but also in endophytic microbe cells

Rasio Senyawa Enansiomer sesamin di dalam kulit batang Pentaspadon motleyi (Anacardiaceae)

The barks of Pentaspadon motleyi Hook. f. (Anacardiaceae) were collected from the Poso district in Central Sulawesi, Indonesia, in 1992 which it has been used traditionally as a remedy for malaria and tuberculosis in the local area. It was found that a mixture of (+)-sesamin (1) and (-)-sesamin (2) in a ratio of 100:86 were present together with lupeol in the bark of Pentaspadon motleyi. This was the first evidence of sesamin being isolated in almost equivalent amounts of (+)- and (-)-forms from a single plant species, and indicates that the biosynthetic pathway of sesamin in the plant is not enantioselective or fuzzy.Kulit batang Pentaspadon motleyi Hook. F (Anacardiaceae ) yang dikoleksi dari daerah Poso (Sulawesi Tengah), Indonesia tahun 1992 dan secara tradisional digunakan untuk pengobatan malaria dan tuberkolosis. Senyawa kimia dalam bentuk campuran (+)-sesamin (1) dan (-)-sesamin (2) dengan perbandingan 100:86 bersama dengan senyawa lupeol telah ditemukan dari kulit batang Pentaspadon motleyi. Ini adalah laporan yang pertama kali bahwa sesamin yang diisolasi yang mempunyai jumlah hampir sama antara (+)-sesamin dan (-)-sesamin dari satu spesies tanaman ini, dan ini menunjukkan bahwa jalan biosíntesis sesamin dalam tanaman tersebut tidak enansioselektif atau tidak begitu jelas

Curcuma longaから分離したDiaporthe属エンドファイト糸状菌を用いたcurcuminから無色還元誘導体への微生物変換(発表論文抄録(2011))

We investigated the microbial conversion of curcumin (1) using endophytic fungi associated with the rhizome of Curcuma longa (Zingiberaceae). We found that Diaporthe sp., an endophytic filamentous fungus, converts curcumin (1) into four colorless derivatives, namely (3R,5R)-tetrahydrocurcumin (2), a novel (3R,5S)-hexahydrocurcumin (3) named neohexahydrocurcumin, (3S,5S)-octahydrocurcumin (4) and meso-octahydrocurcumin (5).We investigated the microbial conversion of curcumin (1) using endophytic fungi associated with the rhizome of Curcuma longa (Zingiberaceae). We found that Diaporthe sp., an endophytic filamentous fungus, converts curcumin (1) into four colorless derivatives, namely (3R,5R)-tetrahydrocurcumin (2), a novel (3R,5S)-hexahydrocurcumin (3) named neohexahydrocurcumin, (3S,5S)-octahydrocurcumin (4) and meso-octahydrocurcumin (5)

Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae

We systematically surveyed period variations of superhumps in SU UMa-type dwarf novae based on newly obtained data and past publications. In many systems, the evolution of superhump period are found to be composed of three distinct stages: early evolutionary stage with a longer superhump period, middle stage with systematically varying periods, final stage with a shorter, stable superhump period. During the middle stage, many systems with superhump periods less than 0.08 d show positive period derivatives. Contrary to the earlier claim, we found no clear evidence for variation of period derivatives between superoutburst of the same object. We present an interpretation that the lengthening of the superhump period is a result of outward propagation of the eccentricity wave and is limited by the radius near the tidal truncation. We interpret that late stage superhumps are rejuvenized excitation of 3:1 resonance when the superhumps in the outer disk is effectively quenched. Many of WZ Sge-type dwarf novae showed long-enduring superhumps during the post-superoutburst stage having periods longer than those during the main superoutburst. The period derivatives in WZ Sge-type dwarf novae are found to be strongly correlated with the fractional superhump excess, or consequently, mass ratio. WZ Sge-type dwarf novae with a long-lasting rebrightening or with multiple rebrightenings tend to have smaller period derivatives and are excellent candidate for the systems around or after the period minimum of evolution of cataclysmic variables (abridged).Comment: 239 pages, 225 figures, PASJ accepte

カガク リテラシー ノ シンコウ カツドウ ニ オケル キョウドウ ノ ヒツヨウセイ ニ ツイテ ノ ケントウ

本稿では、科学リテラシーの振興活動における、多様なアクターによる「協働」の必要性およびそのあり方についての検討を行う。第1節では、日本における科学リテラシー振興のための最も規模の大きな協働であった「科学技術の智」プロジェクトを振り返り、第2節以降は、今後の科学リテラシーの振興のためには、社会の様々なアクターによる協働がより一層必要であることを3つの関連する視点から論じる。まず第2節では、科学リテラシー振興活動の目指す社会と科学技術との間の関係性や、それを支える公共的な価値観について、協働で検討する必要性があることについて論じる。第3節では、個人やコミュニティ、社会といった様々な主体が相互補完的な形で科学リテラシー資源へのアクセスを支え合うような協働について論じる。第4節では、科学リテラシー振興活動の掲げる公共的な価値を実現するためには、仕組みや制度、システムを担う人たちと協働し、それらの整備と併せて科学リテラシーを考える必要があることについて論じる。そして最後に第5節では、前節までに述べた協働を推進するための具体的な活動の例について紹介する。In this paper, the authors argue for the necessity of multi-actor collaboration in discussing and promoting science literacy in our society. First we look back at the Science for All Japanese project − the largest national project for presenting a grand picture of science literacy for the Japanese society − and highlight its nature as a large-scale multi-actor collaboration. We then examine the reasons for which such multi-actor collaboration is even more important today in discussing and promoting science literacy from three inter-related perspectives that include: openly deliberating on public values of science communication; sharing science literacy resources in/among individuals, communities and societies; and exercising science literacy to realise desired science-society relations. The paper concludes with some examples of activities from our previous and current projects on science literacy for putting the ideas presented in this paper into practice