The ChELSI Institute, Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield, UK.
Proteomics. 2011 Feb;11(3):339-51. doi: 10.1002/pmic.201000386. Epub 2011 Jan 3.
Cell surface physicochemical characterization techniques were combined with quantitative changes in protein expression, to investigate the biological and biophysical changes of Escherichia coli MG1655 cells when grown as a biofilm (BIO). The overall surface charge of BIO cells was found to be less negative, highlighting the need for a lower electrophoretic mobility for attachment to occur. Comparison of the chemical functional groups on the cell surface showed similar profiles, with the absorbance intensity higher for proteins and carbohydrates in the BIO cells. Quantitative proteomic analysis demonstrated that 3 proteins were significantly increased, and 9 proteins significantly decreased in abundance, in cells grown as a BIO compared to their planktonic counterparts, with 7 of these total 12 proteins unique to this study. Proteins showing significant increased or decreased abundance include proteins involved in acid resistance, DNA protection and binding and ABC transporters. Further predictive analysis of the metabolic pathways showed an increased abundance of the amino acid metabolism and tricarboxylic acid (TCA) cycle, with a decrease in expression within the pentose phosphate and glycolysis pathways. It is therefore hypothesized that cells grown as a BIO are still energetically viable potentially using amino acids as an indirect carbon backbone source into the TCA cycle.
采用细胞表面物理化学特性分析技术结合蛋白表达的定量变化，研究了大肠杆菌 MG1655 细胞形成生物膜（BIO）时的生物学和生物物理变化。发现 BIO 细胞的整体表面电荷带负电程度较低，这表明其与附着物的结合需要较低的电泳迁移率。对细胞表面化学功能基团的比较表明，生物膜细胞中蛋白质和碳水化合物的吸收强度更高。定量蛋白质组学分析表明，与浮游细胞相比，生物膜细胞中有 3 种蛋白显著增加，9 种蛋白显著减少，这 12 种蛋白中 7 种是本研究特有的。显示蛋白丰度显著增加或减少的蛋白包括参与耐酸、DNA 保护和结合以及 ABC 转运蛋白的蛋白。对代谢途径的进一步预测分析表明，氨基酸代谢和三羧酸（TCA）循环的丰度增加，而戊糖磷酸和糖酵解途径的表达减少。因此，推测生物膜细胞仍然具有活力，可能将氨基酸作为间接碳骨架来源用于 TCA 循环。
