Role of Nonadsorbing Polymers in Bacterial Aggregation

Abstract

Bacteria exhibit properties similar to those of nonbiological colloids and can display pairwise attractions when in close proximity. This interaction is governed by the surface chemistry of the cells. We seek to understand bacterial aggregation at the cellular level using Escherichia coli (E. coli) AB1157. Aggregation studies were carried out using 0.5 to 2.5 wt% E. coli AB1157 harvested in different growth phases with varying concentrations of a nonadsorbing polymer, sodium polystyrene sulfonate (SPS). The electrophoretic mobility of E. coli AB1157 in different growth phases was determined using phase-amplitude light scattering. E. coli AB1157 was found to be negatively charged, and the cell surface properties changed in different growth phases. The electrokinetic results correlated well with the different concentrations of nonadsorbing polymer needed to induce depletion aggregation. This shows that a difference in aggregation properties is due to changes in the bacteria electrokinetic properties during their growth.

<em>Vibrio fischeri</em> and <em>Escherichia coli</em> adhesion tendencies towards photolithographically modified nanosmooth poly (<em>tert</em>-butyl methacrylate) polymer surfaces

“…Electrophoretic mobility (EPM) is a commonly used technique for surface characterization of nonbiological colloids and, more recently, bacterial cells (Tsuneda et al 2003;de Kerchove and Elimelech 2005;Eboigbodin et al 2005Eboigbodin et al , 2006. Cell surface electrokinetic properties are implied from the measurement of the movement of the charged particles eg, cell, in an external electric fi eld to obtain the EPM.…”

“…Cell surface electrokinetic properties are implied from the measurement of the movement of the charged particles eg, cell, in an external electric fi eld to obtain the EPM. The magnitude of the EPM gives an indication of the overall net charge on the surface of a particle where; a negative EPM value indicates that a particle has a negative charge, while a positive EPM value indicates that the particle has a net positive charge (de Kerchove and Elimelech 2005;Eboigbodin et al 2005). Through the application of Smoluchowski's equation EPM is related to the zeta potential, where zeta potential is assumed to be equal to the cellular surface charge (Masliyah 1994;Hunter 1995).…”

“…Hydrophobicity (Reynolds and Wong 1983;Pringle and Fletcher 1986) and simple surface roughness or physical confi guration have also been identifi ed as infl uential factors. Electrokinetic properties have previously been shown to play a fundamental role in bacterial aggregation (Eboigbodin et al 2005). Marshall (1984) proposed that electrokinetic properties were a major factor in the attraction or repulsion of bacterial cells to surfaces.…”

“…Marshall (1984) proposed that electrokinetic properties were a major factor in the attraction or repulsion of bacterial cells to surfaces. Several studies have indicated that bacterial adhesion negatively correlated with bacterial zeta potentials (van Loosdrecht et al 1989;Tsuneda et al 2003;Li and Logan 2004;Tsuneda et al 2004;Eboigbodin et al 2005), conversely, other studies have been reported that there are no relationship between the two parameters (Abbot et al 1983;Hogt et al 1985;Harkes et al 1991). A review by Donlan (2002) has discussed the contribution of bacterial fi mbriae in the surface attachment mechanism.…”

Rapid Determination of Quinoline and 2-Hydroxyquinoline in Quinoline Biodegradation Process by Tri-Wavelength UV/Vis Spectroscopy

“…4) due to the light-scattering effect. 19 Although such effect can be minimized by the sample centrifugation, filtration, or ultra-filtration, it makes the testing more complicated and limits its applications for rapid or on-line measurements of Q and HQ during their conversion process. Figure 4 illustrates that the absorbance at 380 nm was due only to EPS and its absorptions at 326 and 289 nm, overlapped with Q and HQ, are higher than that of 380 nm.…”