Extending the new respiratory paradigm in Bacteroides

扩展拟杆菌的新呼吸范式

• 批准号: 10884591
• 负责人: Blanca Barquera
• 金额: $ 72.21万
• 依托单位: RENSSELAER POLYTECHNIC INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-18 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10884591
• 关键词: Address; Affect; Bacteria; Bacteroides; Bacteroides fragilis; Bile Acids; Biochemical; Biochemistry; Cell Respiration; Cell physiology; Code; Color; Communities; Complex; Consumption; Couples; Cytoplasm; Data; Dependence; Development; Developmental Process; Dietary Polysaccharide; Digestion; Drug Metabolic Detoxication; Ecosystem; Electron Transport; Electrons; Environment; Enzymatic Biochemistry; Enzymes; Fermentation; Food; Formulation; Funding; Generations; Genes; Genetic; Gnotobiotic; Growth; Health; Health Benefit; Human; In Vitro; Industrialization; Inflammation; Intestines; Ion Pumps; Knowledge; Metabolism; Molecular; Monosaccharides; Multienzyme Complexes; NADH; Nitric Oxide; Nitrites; Nutrient; Operon; Oxidants; Pathway interactions; Phenotype; Physiology; Polysaccharides; Population; Probiotics; Process; Production; Protons; Quinones; Regulation; Respiration; Respiratory Chain; Role; Source; Toxic effect; Translating; Variant; Vitamin K 2; Volatile Fatty Acids; Work; antiporter; bacterial fitness; design; dietary; electron donor; experience; experimental study; fitness; gut inflammation; gut microbiota; immunoregulation; improved; in vivo; isoprenoid; member; men; metabolomics; microbial; microbiota; mouse model; nitric oxide reductase; patient population; respiratory; respiratory enzyme; transcription factor; transcriptomics

Project Summary/Abstract Despite the tremendous amount of data that has been generated over the last 15 years regarding the human intestinal microbiota, we still know relatively little about energy generation processes of most of the abundant members of this ecosystem, including the Bacteroides. Our gap in this fundamental knowledge hinders our understanding of interactions between microbial members, how certain conditions in the gut environment affect microbial compositional changes, and how we may appropriately alter the composition of the ecosystem to improve human health. Bacteroides is one of the most abundant and stable bacterial genera of the human intestinal microbiota with strains colonizing their hosts for decades. During the first funding cycle of this project, we demonstrated that Bacteroides have a complex respiratory chain that provides substantial energy during both anaerobic and nanaerobic (0.1-0.15% O2) growth. Our studies revealed complexity at many steps in the respiration pathway and unexpected differences between Bacteroides species that will be pursued in this renewal application. These new aspects of respiration will be addressed in three specific aims. In Aim 1, we will study the important NUO complex that couples the transfer of electrons to menaquinone with creation of the proton gradient. The Bacteroides NUO complex is different than in most studied bacteria. In this aim, we will use genetics and biochemical analyses to conclusively identify the electron donor to NUO, determine the importance of NUO and Na+/H+ antiporters in maintaining the essential proton gradient, and determine the contribution of NUO and Na+/H+ antiporters to bacterial fitness in the mammalian gut. In Aim 2, we will study the acquisition and remodeling of the essential respiration component, menaquinone (MK). Most Bacteroides have all the genes necessary for the de novo synthesis of MK; however, certain Bacteroides species lack the primary men genes and must obtain and remodel dietary and/or microbial sources. We will explore unknown features of MK synthesis including how the isoprenoid chain is cleaved and remodeled, how Bacteroides species without the men operon obtain MK precursors, and the dietary and/or microbiota sources of these precursors. In Aim 3, we will study the NrfHA complex, the genes of which are among the most upregulated during nanaerobic growth. We predict NrfHA is an additional terminal electron donor that functions under nanaerobic conditions and donates electrons to both nitrite and nitric oxide (NO), detoxifying these molecules. We will study the regulation of the nrfHA operon revealing transcriptional factors that upregulate genes during nanaerobic growth, study its ability to donate electrons to both nitrite and NO, and determine if this complex allows Bacteroides to reduce host inflammation and better survive in the inflamed gut. The experiments of this proposal will reveal numerous aspects of basic physiology of the Bacteroides that can be translated for human health benefits.

项目概要/摘要 尽管在过去 15 年中产生了大量关于人类的数据 肠道微生物群，我们对大多数丰富微生物的能量产生过程仍然知之甚少 该生态系统的成员，包括拟杆菌。我们在这一基础知识上的差距阻碍了我们 了解微生物成员之间的相互作用，肠道环境中的某些条件如何影响 微生物组成的变化，以及我们如何适当地改变生态系统的组成 改善人类健康。拟杆菌属是人类最丰富、最稳定的细菌属之一 肠道微生物群及其在宿主体内定殖数十年的菌株。在该项目的第一个资助周期内， 我们证明了拟杆菌有一个复杂的呼吸链，可以在呼吸过程中提供大量能量 厌氧和纳氧（0.1-0.15% O2）生长。我们的研究揭示了许多步骤的复杂性 拟杆菌属物种之间的呼吸途径和意想不到的差异将在 此续订申请。呼吸的这些新方面将通过三个具体目标来解决。瞄准 1，我们将研究重要的 NUO 络合物，该络合物将电子转移与甲基萘醌耦合起来 质子梯度的创建。拟杆菌 NUO 复合体与大多数研究的细菌不同。在 为了实现这一目标，我们将利用遗传学和生化分析来最终确定 NUO 的电子供体， 确定 NUO 和 Na+/H+ 反向转运蛋白在维持基本质子梯度方面的重要性，以及 确定 NUO 和 Na+/H+ 逆向转运蛋白对哺乳动物肠道细菌适应性的贡献。瞄准 2、我们将研究呼吸必需成分甲萘醌（MK）的获取和重塑。 大多数拟杆菌具有从头合成 MK 所需的所有基因；然而，某些 拟杆菌缺乏主要的男性基因，必须获得并重塑饮食和/或微生物 来源。我们将探索 MK 合成的未知特征，包括类异戊二烯链如何裂解 并改造，没有男性操纵子的拟杆菌属如何获得 MK 前体，以及饮食 和/或这些前体的微生物群来源。在目标 3 中，我们将研究 NrfHA 复合体，即 它们是纳米厌氧生长过程中表达最上调的。我们预测 NrfHA 是一个附加终端 在厌氧条件下发挥作用并向亚硝酸盐和硝酸盐提供电子的电子供体 氧化物（NO），对这些分子进行解毒。我们将研究nrfHA操纵子的调控揭示 在厌氧生长过程中上调基因的转录因子，研究其捐赠电子的能力 亚硝酸盐和一氧化氮，并确定该复合物是否允许拟杆菌减少宿主炎症和 更好地在发炎的肠道中生存。该提案的实验将揭示基本的许多方面 拟杆菌的生理学可以转化为人类健康益处。