title: Taking Advantage of Electric Field Induced Bacterial Aggregation for the Study of Interactions between Bacteria and Macromolecules by Capillary Electrophoresis.
abstract: The quantification of interaction stoichiometry and binding constant between bacteria (or other microorganism) and (macro)molecules remains a challenging issue for which only a few adapted methods are available. In this paper, a new methodology was developed for the determination of the interaction stoichiometry and binding constant between bacteria and (macro)molecules. The originality of this work is to take advantage of the bacterial aggregation phenomenon to directly quantify the free ligand concentration in equilibrated bacteria-ligand mixtures using frontal analysis continuous capillary electrophoresis. The described methodology does not require any sample preparation such as filtration step or centrifugation. It was applied to the study of interactions between Erwinia carotovora and different generations of dendrigraft poly-L-lysines leading to quantitative information (i.e., stoichiometry and binding site constant). High stoichiometries in the order of 10(6)-10(7) were determined between nanometric dendrimer-like ligands and the rod-shaped micrometric bacteria. The effect of the dendrimer generation on the binding constant and the stoichiometry is discussed. Stoichiometries were compared with those obtained by replacing the bacteria by polystyrene microbeads to demonstrate the internalization of the ligands inside the bacteria and the increase of the specific surface via the formation of vesicles.
authors.affiliation: †Institut des Biomolécules Max Mousseron (IBMM, UMR 5247 CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier), Place Eugène Bataillon, CC 1706, 34095 Montpellier, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Sisavath
authors.forename: Patrice
authors.initials: P
authors.lastname: Got
authors.affiliation: §Interactions Hôtes-Pathogènes-Environnements (IHPE, UMR 5244), CNRS, Ifremer, Université de Perpignan Via Domitia, Université de Montpellier, Place Eugène Bataillon, CC 80, 34095 Montpellier, France.
authors.forename: Guillaume M
authors.initials: GM
authors.lastname: Charrière
authors.affiliation: §Interactions Hôtes-Pathogènes-Environnements (IHPE, UMR 5244), CNRS, Ifremer, Université de Perpignan Via Domitia, Université de Montpellier, Place Eugène Bataillon, CC 80, 34095 Montpellier, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Destoumieux-Garzon
authors.affiliation: †Institut des Biomolécules Max Mousseron (IBMM, UMR 5247 CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier), Place Eugène Bataillon, CC 1706, 34095 Montpellier, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Cottet
mesh_terms: D018407:Bacterial Physiological Phenomena; D004560:Electricity; D019075:Electrophoresis, Capillary