Graham Robert Leslie James, Sharma Mohit K, Ternan Nigel G, Weatherly D Brent, Tarleton Rick L, McMullan Geoff
School of Biomedical Sciences, University of Ulster, Coleraine, County Londonderry BT52 1SA, UK.
Genome Biol. 2007;8(6):R110. doi: 10.1186/gb-2007-8-6-r110.
The alpha-Proteobacteria are capable of interaction with eukaryotic cells, with some members, such as Ochrobactrum anthropi, capable of acting as human pathogens. O. anthropi has been the cause of a growing number of hospital-acquired infections; however, little is known about its growth, physiology and metabolism. We used proteomics to investigate how protein expression of this organism changes with time during growth.
This first gel-based liquid chromatography-mass spectrometry (GeLC-MS) temporal proteomic analysis of O. anthropi led to the positive identification of 131 proteins. These were functionally classified and physiochemically characterized. Utilizing the emPAI protocol to estimate protein abundance, we assigned molar concentrations to all proteins, and thus were able to identify 19 with significant changes in their expression. Pathway reconstruction led to the identification of a variety of central metabolic pathways, including nucleotide biosynthesis, fatty acid anabolism, glycolysis, TCA cycle and amino acid metabolism. In late phase growth we identified a number of gene products under the control of the oxyR regulon, which is induced in response to oxidative stress and whose protein products have been linked with pathogen survival in response to host immunity reactions.
This study identified distinct proteomic profiles associated with specific growth points for O. anthropi, while the use of emPAI allowed semi-quantitative analyses of protein expression. It was possible to reconstruct central metabolic pathways and infer unique functional and adaptive processes associated with specific growth phases, thereby resulting in a deeper understanding of the physiology and metabolism of this emerging pathogenic bacterium.
α-变形菌能够与真核细胞相互作用，其中一些成员，如嗜人苍白杆菌，可作为人类病原体。嗜人苍白杆菌已成为越来越多医院获得性感染的病因；然而，人们对其生长、生理学和代谢了解甚少。我们利用蛋白质组学研究了该生物体在生长过程中蛋白质表达如何随时间变化。
这是首次对嗜人苍白杆菌进行基于凝胶的液相色谱-质谱联用（GeLC-MS）的时间蛋白质组学分析，成功鉴定出131种蛋白质。对这些蛋白质进行了功能分类和理化特性表征。利用emPAI协议估计蛋白质丰度，我们为所有蛋白质确定了摩尔浓度，从而能够鉴定出19种表达有显著变化的蛋白质。通路重建导致鉴定出多种中心代谢途径，包括核苷酸生物合成、脂肪酸合成代谢、糖酵解、三羧酸循环和氨基酸代谢。在生长后期，我们鉴定出一些受oxyR调控子控制的基因产物，该调控子在氧化应激反应中被诱导，其蛋白质产物与病原体在宿主免疫反应中的存活有关。
本研究确定了与嗜人苍白杆菌特定生长点相关的独特蛋白质组图谱，同时使用emPAI实现了蛋白质表达的半定量分析。重建中心代谢途径并推断与特定生长阶段相关的独特功能和适应性过程成为可能，从而更深入地了解这种新兴病原菌的生理学和代谢。
