Regulation of amino acid uptake in marine unicellular cyanobacteria: light sensing and circadian clocks.

海洋单细胞蓝细菌氨基酸摄取的调节：光传感和生物钟。

• 批准号: NE/C514723/1
• 负责人: Mikhail Zubkov
• 金额: $ 3.89万
• 依托单位: NATIONAL OCEANOGRAPHY CENTRE
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FC514723%2F1
• 关键词: Regulation; amino; acid; uptake; marine

Cyanobacteria numerically dominate the tropical and subtropical regions of the world's oceans with Prochlorococcus being the dominant photosynthetic organism of the open ocean and Synechococcus dominating in oceanic boundaries at low latitudes. Recently it was observed that Prochlorococcus shows a pronounced diel (day-night) periodicity in uptake of dissolved amino acids compared to Synechococcus. These field observations have important ecological implications. For example in the tropical Atlantic Ocean the Prochlorococcus population contributes around 10% and 40% to the total bacterioplankton uptake of amino acids at midday and after dusk, respectively and therefore exerts a considerable pressure on other bacterioplankton populations by consuming a significant proportion of organic nitrogen in already nutrient-depleted oceanic waters. However, field observations alone are insufficient to understand the mechanism regulating organic nutrient uptake. To address this we propose to study this process using cyanobacterial cultures grown in controlled laboratory conditions and to test the hypothesis that the uptake of amino acids, and possibly other organic nitrogen containing compounds, by Prochlorococcus could be regulated either by light and/or a circadian clock. To do this we will use a combination of isotopic tracer and flow cytometric techniques. The cyanobacterial strains will be exposed to various light regimes (varying in quality, quantity, periodicity), loaded with isotopically-labelled precursor molecules, and the cells at various cell cycle stages will be flow sorted to determine cellular uptake rates of the isotopic tracers. The research team for this project will have a unique combination of expertise with marine skills in microbial biogeochemistry, flow cytometry, molecular ecology of cyanobacteria combined with terrestrial background skills in plant photobiology. All necessary capital equipment is available.

蓝细菌在数值上占据了世界海洋的热带和亚热带区域，而氯环球菌是开阔海洋的主要光合生物，而在低纬度地区海洋边界中占主导地位的synechococcus。最近，观察到与综合型相比，甲氯环球菌显示出溶解氨基酸的摄取时明显的二二（昼夜）周期性。这些现场观察具有重要的生态意义。例如，在热带大西洋中，促氯环球菌在中午和黄昏之后分别对氨基酸的总细菌量占10％和40％的贡献，因此，通过在已经营养不良的大量牛油中消耗了大量的有机氮基因，对其他细菌群人群施加了相当大的压力。但是，仅现场观察就不足以了解调节有机营养吸收的机制。为了解决这个问题，我们建议使用在受控实验室条件下生长的蓝细菌培养物研究这一过程，并检验以下假设：氨基酸的摄取，可能是通过二氯环菌的摄入氨基酸，可能是通过光和/或昼夜节律调节的。为此，我们将使用同位素示踪剂和流式细胞仪技术的组合。蓝细菌菌株将暴露于各种光制状态（质量，数量，周期性不同），加载带有同位素标记的前体分子，并且各个细胞周期阶段的细胞将被分类以确定同位素示踪剂的细胞摄取速率。该项目的研究团队将具有独特的专业知识与微生物生物地球化学，流式细胞术，蓝细菌的分子生态学以及植物光生物学中的陆地背景技能相结合的独特组合。所有必要的资本设备都可以使用。