Walker Sharon L, Hill Jane E, Redman Jeremy A, Elimelech Menachem
Department of Chemical and Environmental Engineering, University of California, Riverside, B355 Bourns Hall, Riverside, California 92521, USA.
Appl Environ Microbiol. 2005 Jun;71(6):3093-9. doi: 10.1128/AEM.71.6.3093-3099.2005.
The influence of bacterial growth stage and the evolution of surface macromolecules on cell adhesion have been examined by using a mutant of Escherichia coli K-12. To better understand the adhesion kinetics of bacteria in the mid-exponential and stationary growth phases under flow conditions, deposition experiments were conducted in a well-controlled radial stagnation point flow (RSPF) system. Complementary cell characterization techniques were conducted in combination with the RSPF experiments to evaluate the hydrophobicity, electrophoretic mobility, size, and titratable surface charge of the cells in the two growth phases considered. It was observed that cells in stationary phase were notably more adhesive than those in mid-exponential phase. This behavior is attributed to the high degree of local charge heterogeneity on the outer membranes of stationary-phase cells, which results in decreased electrostatic repulsion between the cells and a quartz surface. The mid-exponential-phase cells, on the other hand, have a more uniform charge distribution on the outer membrane, resulting in greater electrostatic repulsion and, subsequently, less adhesion. Our results suggest that the macromolecules responsible for this phenomenon are outer membrane-bound proteins and lipopolysaccharide-associated functional groups.
利用大肠杆菌K-12的一个突变体，研究了细菌生长阶段和表面大分子的演变对细胞黏附的影响。为了更好地理解在流动条件下处于指数中期和稳定期的细菌的黏附动力学，在一个控制良好的径向驻点流（RSPF）系统中进行了沉积实验。结合RSPF实验，采用互补的细胞表征技术，以评估所考虑的两个生长阶段细胞的疏水性、电泳迁移率、大小和可滴定表面电荷。观察到稳定期的细胞比指数中期的细胞黏附性明显更强。这种行为归因于稳定期细胞外膜上高度的局部电荷异质性，这导致细胞与石英表面之间的静电排斥力降低。另一方面，指数中期的细胞在外膜上具有更均匀的电荷分布，导致更大的静电排斥力，进而黏附性更小。我们的结果表明，导致这种现象的大分子是外膜结合蛋白和脂多糖相关官能团。
