Nonspecific and Specific Adhesion of Bacterial Cells to Membranes

细菌细胞对膜的非特异性和特异性粘附

• 批准号: 9216258
• 负责人: Kimberly Anderson
• 金额: $ 4.25万
• 依托单位: University of Kentucky Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-06-15 至 1993-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9216258&HistoricalAwards=false
• 关键词: Nonspecific; Specific; Adhesion; Bacterial; Cells

This proposal is concerned with studying the adhesion of bacterial cells to membranes which are used in a variety of industrial scale separations technologies such as reverse osmosis and desalination. The adhesion of a cell to a membrane surface is a two step process. First, cells in the vicinity of the membrane surface are immobilized by both long- range colloidal forces such as van der Waals attraction, electrostatic attraction, and short range interactions such as hydrogen bonding. Once immobilized, the cells begin to project structures and synthesize extracellular polymeric molecules which bridge the gap between the cells and the membrane, and firmly adhere the cell to the surface. Experiments will be undertaken in a parallel plate flow chamber which is mounted onto the stage of a phase contrast microscope equipped for videomicroscopy and sensitive light intensity measurement via a photomultiplier tube. The bottom plate of the chamber is a glass slide onto which thin polymeric membranes are cast. The membranes will be made of various polymers such as cellulose acetate and polymethyl methacrylate (PMMA), and these will have different surface charges (characterized by zeta potential measurements) and hydrophobicity (characterized by contact angle measurements). Two experiments will be undertaken using the cell. In the first, a dilute suspension of cells wills be slowly perfused through the chamber, and the cells will be allowed to absorb at low density onto the polymeric membrane support. The separation distance between the cell and the membrane will be measured by total internal reflection microscopy. In this technique a laser beam, impinging against the glass slide at a small angle of incidence, is totally reflected off of the glass surface and produces an evanescent wave which propagates normal to the surface and into the chamber. The scattering of the wave by the cell is detected by the photomultiplier tube, and the distance of separation of the cell from the membrane can be obtained from this measurement. The cell separation distance will be measured as a function of both the polymeric membrane surface charge and hydrophobicity, and the charge and hydrophobicity of the bacterial cell. The latter will be correlated with the growth cycle phase. In the second set of experiments, the detachment to attached cells will be measured as a function of applied shear rate by observing the fate of attached cells by video microscopy as the flow rate through the parallel plate chamber is varied. The detachment characteristics will then be correlated with the distance of separation, and ultimately to the hydrophobicity and surface charge characteristics of the membrane and cell.

该建议涉及研究 细菌细胞到膜，用于各种 工业规模的分离技术，例如反相分离技术， 渗透和脱盐。 细胞粘附于 膜表面是两步过程。 首先，细胞在 膜表面附近被长- 范围胶体力，如货车德瓦尔斯吸引力， 静电吸引和短程相互作用，例如 氢键 一旦固定，细胞开始 工程结构和合成胞外聚合物 在细胞和细胞之间的差距的桥梁分子， 膜，并将细胞牢固地粘附到表面。 实验将在平行板流动中进行 安装在相衬物台上的腔室 配有视频显微镜和感光光的显微镜 通过光电倍增管进行强度测量。 底部 腔室的板是玻璃载玻片，薄 浇铸聚合物膜。 这些膜将由 各种聚合物如醋酸纤维素和聚甲基纤维素 甲基丙烯酸酯（PMMA），这些将有不同的表面 电荷（通过zeta电位测量表征）和 疏水性（通过接触角测量表征）。 将使用该电池进行两个实验。 在 首先，将稀释的细胞悬浮液缓慢灌注， 通过小室，细胞将被允许吸收 以低密度附着在聚合物膜载体上。 的 细胞和膜之间的分离距离将是 通过全内反射显微镜测量。 在这 技术的激光束，撞击在载玻片上， 小角度的入射，是完全反射了 玻璃表面，并产生传播的倏逝波 垂直于表面并进入腔室。 的散射 通过光电倍增管检测池的波， 以及细胞与膜的分离距离 可以从这个测量中得到。 细胞分离 距离将被测量为聚合物的 膜表面电荷和疏水性，以及电荷和 细菌细胞的疏水性。 后者将 与生长周期阶段相关。 在第二盘 在实验中，与附着细胞的分离将是 作为施加的剪切速率的函数通过观察 通过视频显微镜观察贴壁细胞的命运， 改变通过平行板室的速率。 的 然后将分离特征与 分离的距离，并最终到疏水性 以及膜和细胞的表面电荷特性。