Coordination Funds

协调基金

• 批准号: 321538268
• 负责人: Professor Dr. Thomas Schweder
• 金额: --
• 依托单位: Institut für Pharmazie
• 依托单位国家: 德国
• 项目类别: Research Units
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/321538268?language=en
• 关键词: Coordination; Funds

Marine bacteria play an essential role in global carbon cycling: Whilst algae convert carbon dioxide into carbohydrates at a rate of 50 gigatons per year, it is bacterial enzymes that degrade the algal biomass and recycle this carbon – in hitherto unknown quantities. Bacterial action thus dictates how much carbon dioxide is removed from the atmosphere and stored in the ocean (carbon sink) and how much is rechannelled into the carbon cycle. Shedding light on this black box, i.e., elucidating the underlying mechanisms, genes and enzyme repertoires that determine the fate of algal glycans is therefore mandatory for our overall understanding of the ocean’s role in the climate emergency. With these premisses in mind, we bundled our synergistic expertise in bacterial diversity, microbial ecology, (meta)genomics, (meta)proteomics, biochemistry, enzymology, and structural biology, and set out to unravel the physiologies and functions of key bacterial populations during spring phytoplankton blooms. Our studies revealed that algal polysaccharides are degraded by the successive action of numerous highly specialized bacterial strains, each of which targets a different subset of sugar intermediates. We could demonstrate that hundreds of carbohydrate-active enzymes are involved in the cycling of individual algal glycans. Moreover, we recently discovered specific intricate algal glycan structures which, unlike less complex polysaccharides, are difficult to digest and therefore hardly degraded by bacteria during algal blooms. These research efforts of FOR 2406 resulted in more than 25 joint peer-reviewed publications to date. In the third and final phase of the research unit POMPU we will strengthen our focus on protein functions involved in central polysaccharide utilization mechanisms of marine Bacteroidetes. In-depth molecular biological analyses of so-called polysaccharide utilization loci (PULs) and biochemical characterizations of identified key proteins will allow us to determine marine strategies of alpha-mannan-, sulfated xylan- and laminarin utilization. These proteogenomic analyses of cultivable, environmentally relevant key bacteria under defined in vitro conditions will complement our comparative in situ studies on particle-associated and free-living bacteria during phytoplankton blooms. We will elucidate the composition, interaction and function of complex microbiomes of marine particles and their specific glycan-cycling processes. Our interdisciplinary and holistic approach in FOR 2406 is crucial to unravel fundamental molecular mechanisms of marine polysaccharide utilization and will thus ultimately enable us to decipher hitherto unknown facets of global carbon cycling.

海洋细菌在全球碳循环中发挥着至关重要的作用：虽然藻类每年以500亿吨的速度将二氧化碳转化为碳水化合物，但细菌酶能降解藻类的生物量，并以迄今未知的数量回收这些碳。因此，细菌的作用决定了多少二氧化碳从大气中被清除并储存在海洋(碳汇)中，以及有多少二氧化碳被重新引导到碳循环中。因此，阐明这个黑匣子，即阐明决定藻类多糖命运的潜在机制、基因和酶系，对于我们全面了解海洋在气候紧急情况中的作用是必不可少的。考虑到这些前提，我们捆绑了我们在细菌多样性、微生物生态学、(Meta)基因组学、(Meta)蛋白质组学、生物化学、酶学和结构生物学方面的协同专业知识，并着手揭示春季浮游植物水华期间关键细菌种群的生理和功能。我们的研究表明，藻类多糖是通过大量高度专门化的细菌菌株的连续作用而降解的，每一种细菌菌株都针对不同的糖中间体亚群。我们可以证明，数百种碳水化合物活性酶参与了单个藻类多聚糖的循环。此外，我们最近发现了特定的错综复杂的藻类多糖结构，与不太复杂的多糖不同，这种结构很难被消化，因此在藻类水华期间很难被细菌降解。到目前为止，2406年度的这些研究工作产生了25多份联合同行评议出版物。在POMPU研究单元的第三阶段，也是最后阶段，我们将加强对海洋拟杆菌中心多糖利用机制所涉及的蛋白质功能的关注。对所谓的多糖利用位点(Puls)的深入分子生物学分析和已鉴定的关键蛋白质的生化特征将使我们能够确定α-甘露聚糖、硫酸木聚糖和海带多糖的海洋利用策略。这些在确定的体外条件下对可培养的、与环境相关的关键细菌的蛋白质基因组分析将补充我们对浮游植物水华期间颗粒相关细菌和自由生活细菌的比较现场研究。我们将阐明海洋颗粒的复杂微生物群的组成、相互作用和功能及其特定的糖链循环过程。我们在FOR2406中的跨学科和整体方法对于揭开海洋多糖利用的基本分子机制至关重要，因此最终将使我们能够破译迄今未知的全球碳循环方面。