Search

平成26年度宇宙輸送シンポジウム（2015年1月15日-16日. 宇宙航空研究開発機構宇宙科学研究所（JAXA)(ISAS)）, 相模原市, 神奈川県, Space Transportation Symposium FY2014 (January 15-16, 2015. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan, 資料番号: SA6000036053, レポート番号: STCP-2014-053

Studies on chemical structures, metabolisms and physiological significances of food and bioactive natural products are currently being addressed in our laboratory to explain their health effects in humans. Some novel molecules and functions of food and nutrients were discovered, and new foodstuffs and products were developed. The researches were carried out on stable authentic phosphatidylcholine hydroperoxide; membrane lipid glycation and its inhibitors; cancer growth suppression by conjugated triene fatty acids; antiangiogenicity of rice bran tocotrienol; glucosidase inhibition by mulberry 1-deoxynojirimycin; and high quality broccoli products regarding hepatoprotective sulforaphane contents.

Kenaf (Hibiscus cannabinus L.), which can grow rapidly and maintain high primary production, was examined for its ability to decontaminate cadmium ions (Cd) from polluted soil. Although its germination and growth were not affected at first, its photosynthesis dependent growth was disturbed by Cd in the soil. No growth after expanding the true leaves was observed at above 111ppm Cd. At 74.1ppm Cd, kenaf could acclimate and began to grow after a few weeks lag. The biomass increased by 2.4 times from 4 to 6 weeks after sawing. Higher accumulation rates were observed in the plant body at below 74.1ppm Cd. The rate increased to 6.4 times in the plant body at 1.48ppm Cd. Assuming the same productions of kenaf as on the soil without Cd, it could decontaminate 1.48ppm Cd from the polluted soil for ca. 16 years and could more efficiently from the soil containing lower concentrations of Cd. These results suggested the possible phytoremediation with kenaf applied to the polluted soil with lower concentrations of Cd.

Seeds of kenaf(H.cannabinus) could germinate and grow in the soil polluted with 5310 ppm Pb, although their growth was strongly inhibited at first. After the expansion of the third and fourth leaves, older leaves died and fell, followed by the expanding new leaves. During the first 30 days, the numbers of leaves did not increase at a same rate as the control plants growing in soil without pollution. The numbers of leaves were only 9.0 after 30 days and the dry weight of the leaves and stems (upper ground biomass hereafter) was 0.26 g, which was 3.3% of the biomass of the control plants. After the first 30 days, the plants on the polluted soil did not lose their older leaves and began to increase the numbers of leaves. The plants then increased their upper ground biomass rapidly. The upper ground biomass was 59 g after 69 days, which was 32% of the control biomass. These results strongly suggest that seedlings of kenaf can tolerate and acclimate to soils highly polluted with Pb. Although their acclimations took a long period of time, 30 days, kenaf plants could grow normally after the acclimations. The concentrations of Pb in leaves, barks of stems and cores of stems measured by atomic absorption spectrometry were 0.204, 0.211 and 0.407 ppm, respectively. After the acclimations, kenaf accumulated Pb at concentrations lower than 1.0 ppm. Phytoremediation with kenaf is necessary to research acclimations.

Kenaf(British great Kenaf, scientific name Hibiscus cannabinus L) is an annual plant of Malvaceae Hibiscus L. of West African origin, and is remarkable as a new pulp resource. Its ability to fix carbon dioxide is excellent because growth is rapid, and it is reported that its ability equals that of tropical forests. In addition, it is possible to use it for soil cleaning and water quality purification. This research, focussed on kenaf's high water absorption capacity from the soil and its ability., to remove heavy metals from the soil, especially lead, and to reduce ground water pollution. Kenaf was grown in Hyogo Prefectur and kenaf and sorghum were grown in the tropical simulation room in our campus. These plants were burnt to ash, and the total quantity of absorbed lead was measured by atomic absorption spectrometry. Lead absorbed from the soil by kenaf vegetation was also clarified in samples processed with nitric acid. A large amount of lead was accumulated in the wood part but not so much was accumulated in the back or the living parts of the plant. It is recommended that you should harvest to absorb the heavy metal efficiently while growing up.

A fiber optics spectrophotometer (USB2000, OceanOptics, USA) was applied to measure light conditions under sea ice at Saroma-ko Lagoon, Hokkaido Japan, in February and March 2005. One end of a 10 m quartz fiber optics (QP200-2-UV-VIS, OceanOptics, USA) fixed under sea ice led light to the other end, and the spectrophotometer determined the spectrum of the light at the other end on the sea ice. Signals from the spectrophotometer were normalized with the calibration light source (DH2000CAL, OceanOptics, USA) and a program (OOIBase, OOIIrad, OceanOptics, USA) and were determined as irradiance (w m^ mn^). Without the cosine-collector for collecting the light from 180 degrees in front, the fiber optics collected light from a narrow range and showed quite different spectrums from those determined with the cosine-collector. Spectrums with a peak at 570 nm were determined with the cosine-collector and corresponded well with the spectrums often determined at near coastal areas. Photon flux densities (μmol photons s^m^ nm^) were estimated from spectrums determined with the cosine-collector and correlated well (R^2=0.98) with those determined with the quantum sensor (LI-193, LI-COR, USA). These results showed that fiber optics spectrophotometer could determine the light conditions under sea ice both qualitatively and quantitatively.

From cultured cells of micro algal species of Thalassiosira nordenskioeldii Cleve, total DNA was extracted with a buffer containing a chelating agent, Chelex 100. Each DNA fragment for 18s rDNA, 16s rDNA and coxI in nuclear, chloroplastic and mitochondrial genomes, respectively, were amplified from the DNA extracts by polymerase chain reactions, and their sequences were determined. This protocol for determining DNA sequences, was scaled down for the DNA extracts from small amounts of cells. Finally, DNA sequences in genomes were determined with 10 cells collected by a micromanipulation technique. The quantity of cells corresponded to an individual colony of this species. With this protocol, DNA sequences in various regions in genomes of each individual micro algal species living in natural environments can be determined directly, without isolation of strains and cultures.

Diatom species of Coscinodiscus centralis Ehrenberg was widely distributed in North Water Polynya in April and May 1998. This species often showed maximum cell densities near to the sea surfaces. Its photosynthetic rates did not show any photoinhibition up to 475 μmol photons m^s^ and an index of onset of light saturation represented as I_K was 115 μmol photons m^s^. Responses of this species to the strong light intensity at low temperature should be supported both by an initial slope of α and by a maximum rates of p_s^b in photosynthetic rate-light intensity curve (P-I curve). Its a and p_s^b at 0℃ were not similar to those estimated in the past studies in polar sea and were 3.35 × 10^ (mgC mgChla^ hour^)/(μmol photons m^s^) and 3.84 mgC mg Chla^ hour^, respectively. Its higher p_s^b was maintained against suppression of electron transport rates and carboxylation rates by Ribulose bisphosphate carboxylase/oxygenase (RuBisCO) at low temperatures. Relative electron transport rates (ETR) and carboxylation rates by RuBisCO decreased by 60 and 47% with temperature decrease form 10 to 0℃, respectively, although photochemical reactions of quantum yield of photosystem II decreased only by 12%.

平成25年度宇宙輸送シンポジウム（2014年1月16日-17日. 宇宙航空研究開発機構宇宙科学研究所（JAXA)(ISAS)）, 相模原市, 神奈川県, Space Transportation Symposium FY2013 (January 16-17, 2014. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan, 資料番号: SA6000016027, レポート番号: STCP-2013-027

第4回極域科学シンポジウム個別セッション：[OB] 生物圏11月13日（水）13:00-14:15 国立国語研究所 ２階ラウンジ

第4回極域科学シンポジウム個別セッション：[OB] 生物圏11月12日（火）13:00-14:00 国立国語研究所 ２階ラウンジ