| High-throughput Microscopic Analysis of Salmonella Invasion of Host Cells
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Author:
Date:
2018-09-20
[Abstract] Salmonella is a Gram-negative bacterium causing a gastro-enteric disease called salmonellosis. During the first phase of infection, Salmonella uses its flagella to swim near the surface of the epithelial cells and to target specific site of infection. In order to study the selection criteria that determine which host cells are targeted by the pathogen, and to analyze the relation between infecting Salmonella (i.e., cooperation or competition), we have established a high-throughput microscopic assay of HeLa cells sequentially infected with fluorescent bacteria. Using an automated pipeline of image analysis, we quantitatively characterized a multitude of parameters of infected and non-infected cells. Based on this, we established a predictive model that ...
[摘要] 沙门氏菌是革兰氏阴性细菌，引起称为沙门氏菌病的胃肠疾病。在感染的第一阶段，沙门氏菌使用其鞭毛在上皮细胞表面附近游泳并靶向特定的感染部位。为了研究确定哪种宿主细胞被病原体靶向的选择标准，并分析感染沙门氏菌（ ie ，合作或竞争）之间的关系，我们有建立了对荧光细菌依次感染的HeLa细胞的高通量显微镜检测。使用自动化图像分析管道，我们定量表征了感染和未感染细胞的众多参数。基于此，我们建立了一个预测模型，使我们能够识别宿主细胞易受感染的参数。我们发现宿主细胞易损性有两个来源：病原体诱导的细胞易感性从沙门氏菌摄取中出现并持续存在于感染过程的后期阶段;以及与细胞固有属性相关的宿主细胞固有的脆弱性，例如局部细胞拥挤和胆固醇含量。我们的方法基于形态学或分子宿主细胞参数预测单层上皮细胞中沙门氏菌感染的概率。在这里，我们提供了工作流程的详细描述，包括基于计算机的分析管道。我们的方法有可能应用于研究宿主 - 病原体相互作用的其他组合。
【背景】鼠伤寒沙门氏菌血清型鼠伤寒沙门氏菌通过摄入受污染的食物或水感染宿主，引起沙门氏菌病。一旦细菌到达肠道的远端回肠，它们就会侵入广泛的宿主细胞，包括肠上皮细胞（Watson和Holden，2010）。在宿主细胞入侵的第一阶段，沙门氏菌选择其目标，使用其鞭毛游泳并扫描上皮表面（Misselwitz et ...
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| Flow Cytometric Quantification of Fatty Acid Uptake by Mycobacterium tuberculosis in Macrophages
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Author:
Date:
2018-02-20
[Abstract] Mycobacterium tuberculosis (Mtb) has evolved to assimilate fatty acids from its host. However, until recently, there was no reliable way to quantify fatty acid uptake by the bacteria during host cell infection. Here we describe a new method to quantify fatty acid uptake by intracellular bacilli. We infect macrophages with Mtb constitutively expressing mCherry and then metabolically label them with Bodipy-palmitate. Following the labeling procedure, we isolate Mtb-containing phagosomes on a sucrose cushion and disrupt the phagosomes with detergent. After extensive washes, the isolated bacteria are analyzed by flow cytometry to determine the level of Bodipy-palmitate signal associated with the bacteria. Using a Mtb mutant strain defective in fatty acid uptake in liquid culture we ...
[摘要] 结核分枝杆菌（Mtb）已经发展为从其宿主吸收脂肪酸。然而，直到最近，还没有可靠的方法来量化宿主细胞感染期间细菌对脂肪酸的摄取。在这里，我们描述了一种新的方法来量化细胞内杆菌对脂肪酸的摄取。我们用Mtb组成性表达mCherry感染巨噬细胞，然后用Bodipy-palmitate代谢标记它们。标记程序后，我们在蔗糖垫上分离含有Mtb的吞噬体，并用去污剂破坏吞噬体。大量洗涤后，通过流式细胞术分析分离的细菌以确定与细菌相关的Bodipy-棕榈酸酯信号的水平。使用液体培养物中脂肪酸摄取缺陷的Mtb突变株，我们确定该突变体在巨噬细胞感染期间同化比野生型菌株少10倍的Bodipy-棕榈酸酯。脂肪酸摄取的这种定量方法可用于进一步鉴定参与细胞内Mtb和可能的其他细菌的脂质摄取的途径。
【背景】结核分枝杆菌（Mtb）同化宿主来源的脂质（脂肪酸和胆固醇）的能力使得病原体能够在其宿主内存活（Russell等人，2010; Lovewell 等人，2016）。在小鼠感染期间和在人肺组织中，通过巨噬细胞内的Mtb上调胆固醇和脂肪酸代谢相关基因来支持该想法（Schnappinger等人，2003; Rachman等人，2006; Rohde等人，2007;Fontán等人，2008; Tailleux等人，2008; Homolka et al。，2010; Rohde et ...
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