Malt Layla M, Perrett Charlotte A, Humphrey Suzanne, Jepson Mark A
Department of Biochemistry, School of Medical Sciences, University of Bristol, Tyndall Avenue, Bristol, BS8 1TD, UK.
Methods Mol Biol. 2015;1225:165-98. doi: 10.1007/978-1-4939-1625-2_12.
Salmonella enterica is a Gram-negative enteropathogen that can cause localized infections, typically resulting in gastroenteritis, or systemic infection, e.g., typhoid fever, in humans and many other animals. Understanding the mechanisms by which Salmonella induces disease has been the focus of intensive research. This has revealed that Salmonella invasion requires dynamic cross-talk between the microbe and host cells, in which bacterial adherence rapidly leads to a complex sequence of cellular responses initiated by proteins translocated into the host cell by a type 3 secretion system. Once these Salmonella-induced responses have resulted in bacterial invasion, proteins translocated by a second type 3 secretion system initiate further modulation of cellular activities to enable survival and replication of the invading pathogen. Elucidation of the complex and highly dynamic pathogen-host interactions ultimately requires analysis at the level of single cells and single infection events. To achieve this goal, researchers have applied a diverse range of microscopy techniques to analyze Salmonella infection in models ranging from whole animal to isolated cells and simple eukaryotic organisms. For example, electron microscopy and high-resolution light microscopy techniques such as confocal microscopy can reveal the precise location of Salmonella and its relationship to cellular components. Widefield light microscopy is a simpler approach with which to study the interaction of bacteria with host cells and often has advantages for live cell imaging, enabling detailed analysis of the dynamics of infection and cellular responses. Here we review the use of imaging techniques in Salmonella research and compare the capabilities of different classes of microscope to address specific types of research question. We also provide protocols and notes on some microscopy techniques used routinely in our own research.
肠炎沙门氏菌是一种革兰氏阴性肠道病原体，可导致局部感染，通常引起肠胃炎，或在人类和许多其他动物中引发全身感染，如伤寒。了解沙门氏菌诱发疾病的机制一直是深入研究的重点。这已揭示出沙门氏菌的入侵需要微生物与宿主细胞之间进行动态交互，其中细菌黏附会迅速引发一系列复杂的细胞反应，这些反应由通过III型分泌系统转运到宿主细胞中的蛋白质所启动。一旦这些由沙门氏菌诱发的反应导致细菌入侵，由第二个III型分泌系统转运的蛋白质会启动对细胞活动的进一步调节，以使入侵病原体能够存活和复制。阐明复杂且高度动态的病原体-宿主相互作用最终需要在单细胞和单个感染事件层面进行分析。为实现这一目标，研究人员应用了多种显微镜技术，以分析从全动物到分离细胞及简单真核生物等模型中的沙门氏菌感染情况。例如，电子显微镜以及共聚焦显微镜等高分辨率光学显微镜技术能够揭示沙门氏菌的精确位置及其与细胞成分的关系。宽视野光学显微镜是研究细菌与宿主细胞相互作用的一种更简单的方法，并且在活细胞成像方面通常具有优势，能够对感染动态和细胞反应进行详细分析。在此，我们综述成像技术在沙门氏菌研究中的应用，并比较不同类型显微镜在解决特定类型研究问题方面的能力。我们还提供了一些在我们自己的研究中常规使用的显微镜技术的方案和注意事项。
