The Chemical Ecology of Marine Sediment Bacteria

海洋沉积物细菌的化学生态学

• 批准号: 1235142
• 负责人: Paul Jensen
• 金额: $ 70.84万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1235142&HistoricalAwards=false
• 关键词: Chemical; Ecology; Marine; Sediment; Bacteria

Intellectual Merit: This project explores the ecological functions of bacterial secondary metabolites as agents of chemical defense. It targets marine sediments, a major and poorly explored marine biome. The aims are to test three hypotheses related to the effects of bacterial secondary metabolites on co-occurring microorganisms and protistan grazers. The focus is on the bacterial genus Salinispora, which is well defined in terms of its diversity and distributions in marine sediments, and well characterized at the genomic level and in terms of secondary metabolite production. A genetic system recently developed for these bacteria will be employed to establish links between biological activities and specific secondary metabolites. By employing a variety of innovative methodologies including imaging mass spectrometry, it will be possible for the first time to gain insight into the potential roles of Salinispora secondary metabolites in structuring marine sediment microbial communities. The results will have broad implications for our understanding of the factors that regulate the diversity and distributions of bacteria in the marine environment. They will additionally address the supplemental hypothesis that secondary metabolites represent ecotype-defining traits that delineate Salinispora species.The hypotheses to be tested are:H1: Secondary metabolites inhibit microbial competitors,H2: Secondary metabolites affect bacterial community composition, andH3: Secondary metabolites function as invertebrate feeding deterrents. A large collection of diverse, co-occurring microbes will be tested for sensitivity to Salinispora secondary metabolites using a direct challenge assay. These types of assays are highly informative in that they can detect behavioral and morphological responses in addition to toxicity. A recently developed imaging mass spectrometry technique will be used to visualize secondary metabolites associated with any observed biological activities. The results will be linked to existing genome sequences and used to aide in compound identification. The associated pathways will be knocked out to provide experimental support for the biological activities of specific compounds.Given that most marine bacteria are not readily cultured, these experiments will additionally address the effects of secondary metabolites on the sediment bacterial community by employing culture independent techniques. In situ growth chambers and next generation sequencing technologies will be used to test extracts and pure compounds against a natural assemblages of sediment bacteria. The results will inform future cultivation efforts and provide a more comprehensive assessment of the organisms targeted by native chemical defenses. Finally, a robust feeding assay using two model protists will be developed and used to test the roles of bacterial secondary metabolites as invertebrate feeding deterrents. In situ experiments will provide insight into the natural assemblage of invertebrates affected by these defenses. The overall results of these studies have the potential to profoundly impact our understanding of the ecological functions of microbial secondary metabolites and the extent to which these compounds affect community composition.Broader Impacts: This research presents the opportunity to fundamentally advance our understanding of the ecological roles of microbial secondary metabolites in a major marine biome. The activities are highly interdisciplinary and bring together aspects of microbiology, ecology, and marine natural products chemistry in unprecedented ways. It strengthens international collaborations with colleagues in Mexico and includes student and postdoctoral training and outreach to under-represented groups. The later includes participation in the anticipated UCSD/HBCU (Historically Black College and University) program and the UCSD Summer Training Academy for Research in the Sciences (STARS) program. Separate NIH funding will be leveraged to explore the medicinal potential of any new secondary metabolites discovered. These compounds will also be provided to the NIH Molecular Libraries program where they will be made broadly available to the scientific community. The project leverages existing NSF-funded ship time and has the potential to yield new assay models that will be broadly applicable to the chemical ecology research community.

学术成就：本研究项目探讨细菌次级代谢物作为化学防御剂的生态功能。它的目标是海洋沉积物，这是一个主要的海洋生物群落，但勘探不足。其目的是测试三个假设有关的影响细菌次生代谢产物的共生微生物和原生生物食草动物。重点是细菌属Salinispora，这是很好地定义在海洋沉积物中的多样性和分布，以及在基因组水平和次级代谢产物的生产方面的特点。最近为这些细菌开发的遗传系统将用于建立生物活性和特定次级代谢产物之间的联系。通过采用包括成像质谱法在内的各种创新方法，将有可能首次深入了解盐孢菌次级代谢产物在构建海洋沉积物微生物群落中的潜在作用。这些结果将对我们理解调节海洋环境中细菌多样性和分布的因素产生广泛的影响。他们还将讨论补充假设，即次级代谢产物代表生态类型定义的特征，描绘Salinispora species.The假设进行测试：H1：次级代谢产物抑制微生物的竞争对手，H2：次级代谢产物影响细菌群落组成，和H3：次级代谢产物的功能作为无脊椎动物的摄食威慑。将使用直接挑战试验测试大量不同的共存微生物对盐孢菌次级代谢产物的敏感性。这些类型的测定是高度信息化的，因为它们可以检测除了毒性之外的行为和形态学反应。最近开发的成像质谱技术将用于可视化与任何观察到的生物活性相关的次级代谢物。结果将与现有的基因组序列相关联，并用于辅助化合物鉴定。由于大多数海洋细菌不易培养，这些实验将采用非培养技术，额外研究次级代谢物对沉积物细菌群落的影响。原位生长室和下一代测序技术将用于测试提取物和纯化合物对沉积物细菌的自然组合。研究结果将为未来的培养工作提供信息，并对天然化学防御所针对的生物体进行更全面的评估。最后，一个强大的喂养试验，使用两个模式原生生物将开发和用于测试细菌的次级代谢产物作为无脊椎动物摄食威慑的作用。原位实验将提供洞察自然组合的无脊椎动物受这些防御。这些研究的总体结果有可能深刻影响我们对微生物次级代谢产物的生态功能的理解，以及这些化合物影响群落组成的程度。更广泛的影响：这项研究提供了从根本上推进我们对微生物次级代谢产物在主要海洋生物群落中的生态作用的理解的机会。这些活动是高度跨学科的，以前所未有的方式将微生物学、生态学和海洋天然产品化学的各个方面结合在一起。它加强了与墨西哥同事的国际合作，包括学生和博士后培训以及对代表性不足群体的宣传。后者包括参加预期的UCSD/HBCU（历史上的黑人学院和大学）计划和UCSD夏季培训学院的科学研究（STARS）计划。另外，NIH的资金将用于探索发现的任何新的次级代谢产物的药用潜力。这些化合物也将提供给NIH分子图书馆计划，在那里它们将被广泛提供给科学界。该项目利用现有的NSF资助的船舶时间，并有可能产生新的分析模型，将广泛适用于化学生态学研究界。