Molecular Analysis of Metabolites and Signaling Networks in Microbial Symbioses

微生物共生中代谢物和信号网络的分子分析

• 批准号: 8164434
• 负责人: Mohammad R Seyedsayamdost
• 金额: $ 9万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-25 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8164434
• 关键词: Address; Agriculture; Algae; Anabolism; Anti-Bacterial Agents; Area; Bacteria; Biochemical; Biological; Biological Assay; Biological Models; Biological Process; Biology; Carbon; Cell Wall; Chemicals; Chemistry; Cues; Data; Doctor of Philosophy; Educational workshop; Enzymatic Biochemistry; Enzymes; Gene Cluster; Gene Deletion; Gene Fusion; Generations; Genetic; Genetic Screening; Goals; Hybrids; In Vitro; Institution; Interdisciplinary Study; Isotopes; Lead; Learning; Libraries; Lignin; Mediating; Mentors; Methods; Microscopic; Modeling; Molecular; Molecular Analysis; Mutagenesis; Natural Products Chemistry; Nature; Oceans; Oxygen; Pathway interactions; Pharmaceutical Preparations; Pharmacologic Substance; Phase; Plants; Play; Process; Production; Property; Regulation; Research; Role; Roseobacter; Screening procedure; Signal Transduction; Signaling Molecule; Source; Structure; Sulfur; Symbiosis; System; Techniques; Testing; The Sun; Time; Training; Virulence; Work; bacterial genetics; base; homoserine lactone; improved; killings; medical schools; member; microbial; microorganism; mutant; novel; pathogen; programs; quorum sensing; research study; response; senescence; skills; small molecule; symposium; tool

DESCRIPTION (provided by applicant): Symbiotic interactions among microorganisms are abundant in nature. The unusual combination of genetic, biochemical and chemical techniques required to study these interactions has hampered their detailed analysis, and therefore most remain poorly-examined. One of the most abundant and environmentally important symbioses occurs in the oceans between microscopic alga, like Emiliania huxleyi, and bacteria of the roseobacter clade, such as Phaeobacter gallaeciensis. E. huxleyi occupies all sun-lit ocean layers and plays an important role in global oxygen and carbon cycles. It forms massive seasonal blooms, where it intermittently associates with members of the roseobacter clade. Roseobacter are ubiquitous in coastal areas and play a major role in global sulfur cycles. While roseobacter-algal symbioses drive numerous biogeochemical processes, the molecular principles underlying these interactions remain unknown. Our preliminary results have shown that P. gallaeciensis, depending on circumstances, produces a potent, novel metabolite that kills E. huxleyi. The proposed research plan aims to 1) discover global regulators and small molecule signals that mediate or modulate roseobacter-algal interactions, 2) use NMR-based methods to characterize the structures of secondary metabolites produced by roseobacter in response to algal signals, and use bioassays to determine their functions, 3) delineate the biosynthetic pathway of these metabolites by transposon mutagenesis, gene deletions, and enzymatic studies, and 4) uncover how metabolite production is regulated using a combination of genetic and biochemical approaches. Subsequently, these studies will be extended to other roseobacter to examine the generality of the principles uncovered with E. huxleyi and P. gallaeciensis. This research plan will generate the tools needed to characterize many similar environmentally important interactions. Because symbioses contain a poorly-explored reservoir of metabolites with potential pharmaceutical and/or agricultural applications, this proposal could also identify novel and useful molecules. Harvard Medical School offers an intellectual niche and an established research program in this area or work. It consists of leaders in the fields of natural products chemistry and bacterial genetics who will serve as my mentors in the proposed project. Having obtained my PhD in mechanistic enzymology, my short-term goals are to acquire the skills necessary to examine the various aspects of microbial symbioses. In the mentored phase, I will be trained in bacterial genetics, small molecule characterization and relevant bioassays. During this time, I will also attend an advanced bacterial genetics course and other workshops/conferences to learn the scientific techniques and management skills required to be a successful PI. In the independent phase, these methods will be used to uncover the regulation of metabolite production and to examine the biosynthetic enzymes. In the long-term, I plan to lead a multidisciplinary research program in an academic institution to study the underlying chemistry, enzymology and biology of environmentally important symbioses. PUBLIC HEALTH RELEVANCE: A majority of today's pharmaceutical drugs were isolated from natural sources, such as plants and bacteria. To address the need to discover new molecules with improved properties, we will explore the compounds produced by ocean bacteria in response to the algae they interact with, and we will also address the chemical and biological mechanisms through which this interaction occurs. The studies will reveal the general principles governing these unexplored bacterial-algal symbioses and will hopefully yield novel compounds with pharmaceutical value.

描述（由申请人提供）：微生物之间的共生相互作用在自然界中非常丰富。研究这些相互作用所需的遗传、生物化学和化学技术的不寻常组合阻碍了对它们的详细分析，因此大多数仍然没有得到很好的研究。最丰富和对环境最重要的共生体之一发生在海洋中，在微生物之间，如Emiliania huxleyi，和玫瑰花分支的细菌，如Phaeoptera gallaeciensis。E. huxleyi占据了所有阳光照射的海洋层，在全球氧和碳循环中发挥着重要作用。它形成大规模的季节性开花，在那里它间歇地与蔷薇属分支的成员联系在一起。玫瑰花在沿海地区无处不在，在全球硫循环中发挥着重要作用。虽然玫瑰杆菌-藻类共生体驱动了许多生物地球化学过程，但这些相互作用背后的分子原理仍然未知。我们的初步结果表明，根据不同的环境，加拉茨青霉产生一种有效的、新的代谢产物，可以杀死E。huxleyi。拟开展的研究计划旨在：1）发现调控蔷薇杆菌-藻类相互作用的全局调节因子和小分子信号，2）利用基于NMR的方法表征蔷薇杆菌响应藻类信号产生的次级代谢产物的结构，并利用生物测定确定其功能，3）通过转座子诱变、基因缺失、和酶的研究，和4）揭示如何代谢产物的生产是调节使用遗传和生物化学方法的组合。随后，这些研究将扩展到其他玫瑰花，以检查E。huxleyi和加来西赤藓（P. gallaeciensis）。这项研究计划将产生所需的工具来描述许多类似的环境重要的相互作用。由于共生体含有具有潜在的药物和/或农业应用的代谢物的未充分开发的储库，因此该提议还可以鉴定新颖且有用的分子。哈佛医学院在这一领域或工作中提供了一个智力利基和一个既定的研究计划。它由天然产物化学和细菌遗传学领域的领导者组成，他们将在拟议的项目中担任我的导师。在获得机械酶学博士学位后，我的短期目标是获得必要的技能，以研究微生物共生的各个方面。在指导阶段，我将接受细菌遗传学，小分子表征和相关生物测定的培训。在此期间，我还将参加先进的细菌遗传学课程和其他研讨会/会议，学习成为一名成功的PI所需的科学技术和管理技能。在独立阶段，这些方法将用于揭示代谢产物产生的调节，并检查生物合成酶。从长远来看，我计划在一个学术机构领导一个多学科的研究项目，研究环境重要共生体的基础化学，酶学和生物学。 公共卫生相关性：当今的大多数药物都是从植物和细菌等天然来源中分离出来的。为了满足发现具有改进特性的新分子的需求，我们将探索海洋细菌响应与它们相互作用的藻类而产生的化合物，我们还将解决这种相互作用发生的化学和生物机制。这些研究将揭示这些未探索的细菌-藻类共生的一般原理，并有望产生具有药用价值的新型化合物。