Structural Biology of Bacillus subtilis Biofilms

微生物形成表面附着的群落，称为生物膜，它促进一种协同的生活方式，其中细胞外基质(ECM)提供对环境应激的保护，包括宿主免疫反应或抗生素治疗。显然，它们的发生可能会产生健康并发症，例如与植入物或牙齿有关的并发症。理解ECM的形成原则是很重要的，特别是因为它的组成部分不仅服务于结构功能，而且还可以参与信号传递过程。对ECM结构和功能的了解的改进可以开发新的和更好地量身定做的抗菌治疗，特别是针对生物被膜形成(抗药性)病原体的治疗。然而，缺乏从分子水平上研究体内情况的方法学方法。固体核磁共振、电子显微镜和质谱学成像技术的最新发展为研究ECM，特别是单个组分的分布及其相互作用提供了前所未有的视角。在这里，革兰氏阳性菌枯草杆菌的生物膜作为一个模型系统。他们是有吸引力的目标，因为有一些机械研究可以推动后续调查。首先，我们测定了TASA纤维的体内结构，利用生物物理技术和结构方法研究了它们与TAPA和EPS在体外和生物膜中的相互作用，并研究了整体生物膜的组成。该项目的长期目标是全面、充分地分辨不同尺度上的生物膜结构。一个长期的目标是检测整个生物膜或ECM内大小成分的梯度。这些结果对了解炭疽杆菌和金黄色葡萄球菌的存活率和感染性具有重要意义。

Microorganisms form surface-attached communities, termed biofilms, which promote a synergistic lifestyle where an extracellular matrix (ECM) provides protection against environmental stress, including host immune reactions or antibiotic treatment. Evidently, their occurrence may produce health complications, for example in connection with implants or on teeth. The principles according to which the ECM is formed are important to understand, especially as its components do not only serve structural functions but can also be involved in signalling processes. An improved knowledge on the structure and function of the ECM could allow the development of new and better tailored antibacterial treatments, particularly those directed against biofilm forming (antibiotic-resistant) pathogens. Yet, there is a lack of methodological approaches for investigating the in vivo situation on the molecular level. Recent developments in solid-state NMR, electron microscopy and imaging by mass spectrometry promise access to unprecedented views into the ECM and in particular into the distribution of individual components and their interactions. Here, biofilms of the gram-positive organism B. subtilis serve as a model system. They are attractive targets, since a number of mechanistic studies are available that fuel follow-up investigations. As a start, we determine the in-vivo structure of TasA fibrils, investigate their interactions with TapA and EPS in vitro and in biofilms by biophysical techniques and structural methods, and study overall biofilm composition. The long-term goal of this project is a comprehensive, sufficiently resolved representation of biofilm structure at various scales. A long-term aim is the detection of gradients of large or small components over an entire biofilm or within the ECM. The results are relevant for understanding B.anthracis and B.aureus survival and infectivity.