Collaborative Research: Vitamin B1 Limitation and Advantageous Use of B1-related Compounds by Marine Bacterioplankton.

浮游海洋细菌显著影响全球元素循环、生产力和水质。最近的证据表明，丰富多样的海洋浮游细菌需要外部维生素B1或前体（这里是B1）才能生存，而这些营养物质的添加会刺激细菌的产生。这表明大多数海洋细菌依赖供应的B1是有利的，使B1动力学成为研究浮游微生物群内营养交换的环境相关试验案例。然而，值得注意的是，细胞外B1可用性与海洋细菌的组成、功能和适应性之间的联系尚不清楚。该项目揭示了1)哪些活动和相互作用是由B1可用性调节的，以及2)普遍存在的海洋浮游细菌使用外源B1的益处。正在进行实验，以解决有关天然浮游细菌B1限制的不确定性，帮助预测浮游生物对自然或人为B1增加的反应，并揭示更多关于浮游生物之间营养交换的规则。更多地了解细菌B1使用的优势将有利于海洋学以外的领域，例如侧重于流线型微生物产品生成的合成生物学。动物b1缺乏症是目前海洋生态系统关注的问题。对微生物水平的成本和配额的更多了解将使更大的群落在其他营养水平上提出缺陷问题。该项目的教学和培训部分包括对研究生和博士后学者的支持。主要的外联部分是新构思的移动水生微生物实验室（MAML），旨在提高公众对水生微生物及其生态系统影响的认识，以及传达营养限制和细胞为什么需要维生素的概念。评估前后和社会距离措施被纳入MAML，鼓励参与者通过社交媒体分享图像并为该计划做出贡献。本项目研究了维生素B1和B1同系物对海洋生态系统中浮游细菌的影响，在这些生态系统中，人们对维生素的限制知之甚少。这项工作是在美国下游第二大河口纽斯河河口和近海沿海进行的。正在进行营养修正实验，以测试B1/同系物是否调节浮游细菌的生长、组成和基因转录（反映假定的功能）。目前正在对野生型和基因工程浮游细菌进行补充性的实验室实验，以测试外源B1/同源物的使用是否能显著提高细胞适应性，并解释为什么对外源B1/同源物的依赖在野生浮游细菌中如此普遍。正在对分离物进行更多的实验室实验，以检查B1从头生物合成与外源B1/同源物使用的蛋白质相关成本，以及使用质谱技术检查B1和前体的细胞配额。这项工作超越了最近基于基因组的推断，解决了外源B1/同系物有效性如何影响浮游细菌代谢、群落结构、微生物相互作用和适应性。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Planktonic marine bacteria significantly impact global elemental cycling, productivity, and water quality. Recent evidence shows that abundant and diverse marine bacterioplankton require external vitamin B1 or precursors (B1 herein) to survive, and addition of these nutrients stimulates bacterial production. This suggests that it is favorable for most marine bacteria to rely on supplied B1, making B1 dynamics an environmentally relevant test case to study nutrient exchanges within the planktonic microbiome. Notably though, links between extracellular B1 availability and the composition, function, and fitness of marine bacteria are poorly understood. This project sheds light on 1) which activities and interactions are modulated by B1 availability, and 2) the benefits of exogenous B1 use by ubiquitous marine bacterioplankton. Experiments are being conducted to address uncertainty regarding B1 limitation of natural bacterioplankton, help predict plankton responses to natural or anthropogenic increases in B1 and reveal more on the rules governing nutrient exchange between plankton. Greater knowledge of the advantages of bacterial B1 use will benefit fields beyond oceanography, such as synthetic biology which focuses on streamlined microbial product generation. B1-deficiency in animals is a current concern in marine ecosystems. Greater knowledge of costs and quotas at the microbial level will position the larger community to ask deficiency questions at other trophic levels. The teaching and training components of this project include support for graduate students and a post-doctoral scholar. The major outreach component is a newly conceived Mobile Aquatic Microbial Laboratory (MAML) that seeks to improve public awareness of aquatic microbes and their ecosystem impact, as well as convey concepts of nutrient limitation and why cells need vitamins. Pre- and post-assessment and social distancing measures are integrated into MAML, as are incentives for participants to share images via social media and contribute to the program.This project investigates the impact of vitamin B1 and B1 congeners on bacterioplankton in marine ecosystems where vitamin limitation is poorly understood. The work is conducted in the Neuse River estuary, the second largest estuary in the lower USA, and in the offshore coastal ocean. Nutrient amendment experiments are being conducted to test whether B1/congeners modulate bacterioplankton growth, composition, and gene transcription (reflecting putative function). Complementary lab-based experiments with wildtype and genetically engineered bacterioplankton are being conducted to test whether use of exogenous B1/congener significantly improves cell fitness and to address why reliance upon exogenous B1/congener is so prevalent among wild bacterioplankton. Additional lab experiments with isolates are being conducted to examine the protein-related cost of B1 de novo biosynthesis versus exogenous B1/congener use as well as cell quotas of B1 and precursors using mass spectrometry techniques. The work reaches beyond recent genome-based extrapolations to address how exogenous B1/congener availability shapes bacterioplankton metabolism, community structure, microbial interactions, and fitness.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.