title: Synchronization of Dictyostelium discoideum adhesion and spreading using electrostatic forces.
abstract: Synchronization of cell spreading is valuable for the study of molecular events involved in the formation of adhesive contacts with the substrate. At a low ionic concentration (0.17 mM) Dictyostelium discoideum cells levitate over negatively charged surfaces due to electrostatic repulsion. First, a two-chamber device, divided by a porous membrane, allows to quickly increase the ionic concentration around the levitating cells. In this way, a good synchronization was obtained, the onsets of cell spreading being separated by less than 5 s. Secondly applying a high potential pulse (2.5 V/Ref, 0.1s) to an Indium Tin Oxide surface attracts the cells toward the surface where they synchronously spread as monitored by LimE(Deltacoil)-GFP. During spreading, actin polymerizes in series of active spots. On average, the first spot appears 8-11s after the electric pulse and the next ones appear regularly, separated by about 10s. Synchronized actin-polymerization activity continues for 40s. Using an electric pulse to control the exact time point at which cells contact the surface has allowed for the first time to quantify the cellular response time for actin polymerization. Electrochemical synchronization is therefore a valuable tool to study intracellular responses to contact.
authors.affiliation: Laboratoire d'Electrochimie et de Physico-chimie des Matériaux et des Interfaces (LEPMI), Grenoble Institute of Technology, 1130 Rue de la Piscine, BP 75, 38402 Saint-Martin d'Hères Cedex, France. m_socol2000@yahoo.com
authors.forename: Marius
authors.initials: M
authors.lastname: Socol
authors.forename: Christine
authors.initials: C
authors.lastname: Lefrou
authors.forename: Franz
authors.initials: F
authors.lastname: Bruckert
authors.forename: Didier
authors.initials: D
authors.lastname: Delabouglise
authors.forename: Marianne
authors.initials: M
authors.lastname: Weidenhaupt
mesh_terms: D000199:Actins / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology; D002465:Cell Movement / Q000502:physiology*; D004023:Dictyostelium / Q000166:cytology* / Q000502:physiology*; D004563:Electrochemistry; D055724:Electrophysiological Phenomena; D005453:Fluorescence; D049452:Green Fluorescent Proteins / Q000032:analysis; D007425:Intracellular Membranes / Q000378:metabolism; D008857:Microscopy, Interference; D055672:Static Electricity; D017971:Tin Compounds / Q000737:chemistry
chemical_list: D000199:Actins; D017971:Tin Compounds; D049452:Green Fluorescent Proteins; C109984:indium tin oxide