水圏基礎生産者の増殖と代謝

1989 Fiscal Year Annual Research Report

• Project/Area Number: 63304002
• Research Institution: The University of Tokyo
• Principal Investigator: 高橋 正征 東京大学, 理学部, 助教授 (50111357)
• Co-Investigator(Kenkyū-buntansha): 猪川 倫好 筑波大学, 生物科学系, 教授 (50015541) ; 渡辺 泰徳 東京都立大学, 理学部, 助手 ; 尊 慶明 筑波大学, 生物科学系, 助教授 (60111358) ; 濱 健夫 名古屋大学, 水圏科学研究所, 助手 (30156385) ; 加藤 憲二 信州大学, 医療短期大学部, 助教授 (70169499)
• Keywords: 基礎生産 / 藻類 / 増殖 / 代謝 / 光 / 栄養物質

Research Abstract

昨年度実施した藻類株の単離作業にもとづいて、中心珪藻類Chaetoceros pseudocurvisetus、藍藻類Synechococcus,Synechocystis Trichodesmium、ラフィド藻類Heterosigma akashiwoを研究材料に選び、バッチおよびケモスタット培養により栄養物質又は光強度を制御して、それぞれの藻類種の代謝と増殖応答を生理生態学的に検討した。実験が年度末まで続いたため実験結果は整理中のものもあり、まだ全体の研究概要の提出できる状況ではなく、以下に整理の済んだ分を報告する。
富栄養フラックスを生育場とする種類では、富栄養フラックス下では葉緑体内のチラコイド・ラメラ相が厚く充実し、光合成産物もタンパク質合成を盛んに行なったのに対し、貧栄養フラックス下におくとチラコイド・ラメラ相が貧弱化し、貧合成産物も種が大部分になった。極端に原栄養フラックスにちると休眠細胞、休眠胞子を形成した。これに対し貧栄養フラックスを生育場にする種類では、栄養フラックスに対応した変化が前者のように顕著ではなかった。細胞生長・分裂時の核DNA量の挙動を把握するたるために、DNAをDAPI染色して顕微分光定量する際のクロロフィル蛍光によるクエンチングを、予じめ細胞をメタノ-ル処理してクロロフイルを抽出除去する方法を工夫して分析精度を向上させた。光合成系の明・暗調節誘導信号がチトクロムb_6-fの状態から発せられたことを明らかにした。貧栄養フラックス状態で栄養塩類濃縮能をもつ種類のいることを単雑株の実験で確認した。trichodesmiumの窒素固定能の発現と窒素源環境との関係を完全人工培地を用いて調べ、NO_3^-NH_3尿素のいづれもが低濃度で窒素固定活性を抑制し、尿素以外ではニトロゲナ-ゼタンパク質の合成は抑制せず、不活性型で存在し、従って窒素源の存在による窒素固定活性の発現がニトロゲナ-ゼ遺伝子の発現と活性化の2段階の制御によることが判明した。

Research Products

• [Publications] Takahashi,K.and T.Ikawa: "The characteristics of photosynthesis and carbon metabolism in Heterosigma akashiwo(Raphidophyceae)" Japanese Journal of Phycology. 36. 202-211 (1988)
• [Publications] Takahashi,K.and T.Ikawa: "Effect of nitrogen starvation on photosynthetic carbon metabolism in Heterosigma akashiwo(Raphidophyceae)" Japanese Journal of Phycology. 36. 212-220 (1988)
• [Publications] Takahashi,K.and T.Ikawa: "Effect of nitrogen starvationon on the diurnal variations of photosynthetic CO_2 fixation in Heterosigma akashiwo(Raphidophyceae)"
• [Publications] Suzuki,K.,Iwamoto,K.and t.Ikawa: "The occurrence of glycolate dehydrogenase and glycolate oxidase in Chromophyte"
• [Publications] Amemiya.Y.,K.Kato,T.Okino and O.Nakayama: "Changes in the chemical composition of carbohydrates and proteins in surface water during the bloom of microcystis in Lake suwa" Ecological Research. (1990)
• [Publications] Fujita,Y.,Y.Iwama,K.Ohki,A.Murakami and N.Hagiwara: "Regulation of the size of light-harvesting anthennae in resonse to light intensity in the green algae Chlorella pyrenoidosa" Plant and Cell Physiology. 30. 1029-1037 (1989)
• [Publications] Fujita,Y.: "Regulation of stoichiometry among thylakoid components in response to light regime:a story on a dynamic nature of cyanobacterial thylakoid system" In Regulation of Photosynthetic Responses,a special issue of Botanical Magazine,Tokyo(R.Kanai,S,Miyachi and S.Katoh,eds.). (1990)
• [Publications] Reuter,J.G.,K.Ohki: "The effect of iron nutrition on photosynthesis and nitrogen fixation in cultures of Trichodesmium(Cyanophyceae)" Journal of Phycology. (1990)
• [Publications] Takahashi,M.and Y.Hara: "Control of diel vertical migration and cell division rhythm of Heterosigma akashiwo by day and night cycle" In Red tides:biology,environmental science,and tosxicology(T.Okaichi,D M.Andeson and T,Nemoto,eds.). 265-268 (1989)
• [Publications] Takahashi,M.,S.Ichimura,M.Kishino and N.Okami: "Shade and chromatic adaptation of phytoplnkton photosynthesis in a thermally stratified sea" Marine Biology. 100. 401-409 (1990)
• [Publications] Kudoh,s.and M.Takahashi: "Physico-chemical control of the growth of a diatom,Asterionella formosa Hass.,in a shallow eutrophic lake" Journal of Plankton Research. 11. 1001-1019 (1990)
• [Publications] Kudoh,s.and M.takahashi: "Fungal control of Population changes of the planktonic diatom Asterionella formosa in a shallow eutrophic lake" Journal of Phycology. (1990)
• [Publications] Kudoh,S.,J.Kanda and M.Takahashi: "Specific growth rates and grazing mortality of chroococcoid cyanobacteria(Synechococcus spp.)in pelagic surface waters in the sea" Journal of the Experimental Marine Biology and Ecology.
• [Publications] Fujita,Y.,A.Murakami and K.Ohki: "Regulation of stoichiometry of thlakoid components in the photosynthetic system of cyanophytes:model experiments showing that control of the synthesis or supply of Chla can chang the stoichiometric relationship" Plant and Cell Physiology. 31. (1990)
• [Publications] K.Ohki,J.P.Zehr,P.G.Falkowski and Y.Fujita: "Regulation of nitrogenase by different nitrogen source in the marine, non-heterocystous syanobacterium Trichodesmium sp." Archives of Microbiology.
• [Publications] Adhikary,S.P.,A.Murakami,K.Ohki and Y.Fujita: "Photoragulation of respiratory activity in the cyanophyte synechocystic PCC6714:a possibility of a simultaneous regulation of content of PS I complex and functional size of resiratory terminal oxidase" Plant and Cell Physiology.
• [Publications] Hama,T.,K.Matsunaga,N.Handa and M.Takahashi: "Composition of photosynthetic products in Lake Biwa,Japan:vertical and seasonal changes and their relation to environmental factors" Journal of Plankton Research. 12. 113-147 (1990)
• [Publications] Hama,T.: "Primary productivity and photosynthetic products around the Kuroshio warm-core ring" Deep-Sea Reserch. (1990)
• [Publications] Hama,T.: "Application of ^<13>C-GC-MS method to the determination of fatty acid composition of photosynthetic products"
• [Publications] Hama,T.,K.Matsunaga,N.Handa and M.Takahashi: "Seasonal change in the fatty acid composition of photosynthetic products in Lake biwa"
• [Publications] Tsuji,T.and K.Ohki: "Analysis of phtosynthetic pigment of individual phytoplankton cells in seas and lakes by microscope spectrofluorometry" InProceedings in the 5th International Symposium on Microbial Ecology. 702-706 (1989)
• [Publications] Hama,T.,K.Matsunaga,N.Handa and M.Takahashi: "Nitrogen budget in the euphotic zone of Lake Biwa from spring to summer,1986" Journal of plankton Research. 12. 125-131 (1990)