Structure and Function of Bacterial Nanowires

细菌纳米线的结构和功能

• 批准号: RGPIN-2020-04837
• 负责人: Strauss, Mike
• 金额: $ 2.99万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=740246
• 关键词: Structure; Function; Bacterial; Nanowires

Bacterial nanowires are naturally occurring electrically conductive extensions produced by some anaerobic bacteria, including Geobacter sulfurreducens. They are primarily used to find electron acceptors in the environment so the bacteria can shed excess electrons produced during respiration, which is particularly relevant when oxygen is not available. These same bacterial strains can also form biofilms, and in these biofilms the nanowires link into a large network of nanowires. Networks can in some cases include nanowires from bacteria of a different species, which increases the likelihood of finding an electron acceptor. This network of natural electron-emitting bacterial nanowires has great potential for use as a microbial fuel cells, where we can gain electrical energy directly from the organisms. The goal of the proposed research is to elucidate the mechanism of electrical conduction through bacterial nanowires in biofilms. Our recent publication on a previously unknown cytochrome-based nanowire (OmcS) demonstrates how much is to be learned about the molecular mechanisms of conduction in protein filaments. Key questions we will address include: How many different types of conductive filaments exist? How is electricity conducted along a pilus? Is the regular array within the pilus disrupted when a neighbouring pilus makes contact, and if so, how is conductivity maintained? Do biofilms produce thick cables of conductive nanowires, or is the network delocalised? We will study nanowires from G. sulfurreducens as a representative system of bacterial nanowires using cryoelectron microscopy and single particle analysis for isolated nanowires, as well as focused ion beam (FIB)-milled biofilms and electron tomography for in situ studies of biofilms. This work will help us understand how bacteria work together in a network, and what limitations are inherent to the function of a biofilm. We expect that with some modifications to the structure of the nanowires, we can improve efficiency of electric conduction, leading to the design of an improved microbial fuel cell. Additionally, this research will help establish an important scientific method in Canada for the first time, in situ imaging of cells and cellular networks with molecular detail. The combination of FIB milling and cryo-electron tomography is proving to be very powerful, and its introduction into the Canadian research community is likely to have a strong impact and augment the work of many groups across the country.

细菌纳米线是一些厌氧细菌产生的自然导电延伸，包括硫还原地杆菌。它们主要用于在环境中寻找电子受体，这样细菌就可以释放在呼吸过程中产生的多余电子，这在氧气不可用的情况下尤其相关。这些细菌菌株也可以形成生物膜，在这些生物膜中，纳米线连接到一个巨大的纳米线网络。在某些情况下，网络可能包括来自不同物种细菌的纳米线，这增加了找到电子受体的可能性。这种天然发射电子的细菌纳米线网络具有作为微生物燃料电池的巨大潜力，在那里我们可以直接从生物体中获得电能。这项研究的目的是阐明细菌纳米线在生物膜中的导电机制。我们最近发表的一种以前未知的基于细胞色素的纳米线(OMCs)展示了对蛋白质细丝传导的分子机制有多少需要了解。我们将解决的关键问题包括：有多少种不同类型的导电丝？电流是如何沿着皮卢斯传导的？当邻近的菌毛接触时，菌毛内的规则阵列会被破坏吗？如果是，如何保持导电性？生物膜会产生粗大的导电纳米线电缆，还是网络会错位？我们将使用冷冻电子显微镜和单粒子分析对分离的纳米线进行研究，并使用聚焦离子束(FIB)球磨生物膜和电子断层扫描对生物膜进行原位研究，以研究硫还原菌纳米线作为细菌纳米线的代表系统。这项工作将帮助我们了解细菌如何在网络中共同工作，以及生物膜的功能固有的限制。我们希望通过对纳米线的结构进行一些修改，可以提高导电效率，从而设计出一种改进的微生物燃料电池。此外，这项研究将有助于在加拿大首次建立一种重要的科学方法，即用分子细节对细胞和细胞网络进行原位成像。事实证明，FIB球磨和冷冻电子断层扫描的结合非常强大，它引入加拿大研究界可能会产生强大的影响，并加强全国许多小组的工作。