Degradation of Collidal Organic Matter in Seawater

海水中胶体有机物的降解

• 批准号: 08458142
• 负责人: NAGATA Toshi
• 金额: $ 4.35万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08458142/
• 关键词: Ocean; Dissolved Organic Matter; Bacteria; Protein; Carbon Cycle; Hydrolytic Enzyme; Greenhouse Effect; Degradation; 炭素循環; 微生物; アミノ酸; 細胞外酵素

In order to better understand the carbon cycle in the upper oceans, we examined degradation by natural bacterioplankton of membrane and soluble proteins prepared from the marine bacterium, Vibrio alginolyticus, radiolabeled with ^3H-or ^<14>C leucine. First order kinetic constants indicated that proteins in crude mambrane extract are degraded at significantly slower rates than the soluble proteins. Proteins determined to be intimately associated with the membrane were not degraded over two days, while a substantial fraction of soluble proteins was degraded during the same period. The data are consistent with a model that membrane and cell wall materials severely restrict access of bacterial proteases to membrane proteins. Our data support the hypothesis that macromolecular organic complexes play a role in temporary storage of dissolved organic carbon (DOC) in seawater. The results are also consistent with recent finding that bacterial membrane protein accumulates in seawater. The formation of a large pool of refractory DOC in seawater may influence carbon cycling in the ocean and changes in atmospheric concentrations of carbon dioxide, the most important greenhouse gas on our planet.

为了更好地了解上层海洋的碳循环，我们检查了天然浮游细菌对由海洋细菌溶藻弧菌制备的膜和可溶性蛋白质的降解，并用^ 3 H-或^ 14 C亮氨酸进行放射性标记。一级动力学常数表明粗制膜提取物中的蛋白质降解速度明显慢于可溶性蛋白质。确定与膜密切相关的蛋白质在两天内没有降解，而大部分可溶性蛋白质在同一时期内被降解。这些数据与膜和细胞壁材料严重限制细菌蛋白酶接触膜蛋白的模型一致。我们的数据支持这样的假设：大分子有机复合物在海水中溶解的有机碳（DOC）的临时储存中发挥着作用。该结果也与最近发现的细菌膜蛋白在海水中积累的结果一致。海水中大量难降解 DOC 的形成可能会影响海洋中的碳循环以及大气中二氧化碳（地球上最重要的温室气体）浓度的变化。

项目成果

Nagaata, T.: "Roles of submicron Particles and colloids food webs and biogeichemical fluxes within marine enviromments" Advances in Microbial Ecology. 15. 81-103 (1997)

Nagaata, T.：“亚微米颗粒和胶体食物网的作用以及海洋环境中的生物化学通量”微生物生态学进展。

永田 俊: "Roles of submicron particles and colloids in microbial food webs and biogeochemical cycles within marine environments" Advances in Microbial Ecology. 15(印刷中).

Shun Nagata：“亚微米颗粒和胶体在海洋环境中微生物食物网和生物地球化学循环中的作用”微生物生态学进展 15（出版中）。

Nagata, T.: "Degradation by bouteria of miembrane and saluble protein in seawnte" Aquatic Microbial Ecology. 印刷中. (1998)

Nagata, T.：“seawnte 中膜和可溶性蛋白质的降解”水生微生物生态学（1998 年）。

Nagata, T.and Kirchman, D.L.: "Roles of submicron particles and colloids in microbial food webs and biogeochemical cycles within marine environments" Advances in Microbial Ecology. 15. 81-103 (1997)

Nagata, T. 和 Kirchman, D.L.：“亚微米颗粒和胶体在海洋环境中微生物食物网和生物地球化学循环中的作用”微生物生态学进展。

Nagata,T.: "Degradation by bacteria of membrane and soluble protein in seawater" Aquatic Microbial Ecology. (印刷中). (1998)

Nagata, T.：“海水中膜和可溶性蛋白质的细菌降解”水生微生物生态学（出版中）。