title: 1/f ruffle oscillations in plasma membranes of amphibian epithelial cells under normal and inverted gravitational orientations.
abstract: Membrane ruffle fluctuations of amphibian epithelial cells A6 (CCL102) cultured in normal and upside down oriented plates have been analyzed through video microscopy. Our results reveal that their edge ruffle fluctuations exhibit a stochastic dynamics with 1/f(alpha) power spectrum over at least two decades at low frequencies and long range correlated, self-affine lateral border profiles. In a few and small areas of the membrane, probably nearby focal contacts, we found periodic oscillations which could be induced by myosin driven contraction of stress fibers. Furthermore, whereas the different gravitational orientations had none or little effect on the structure (power spectra and surface roughness) of these membrane ruffle fluctuations, their dynamic parameters were differentially affected. Indeed, the decay time of ruffles remained unchanged, but the period of lamellipodia oscillations near the focal adhesion points was significantly altered in A6 cells cultured upside down.
authors.affiliation: Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife PE, Brazil.
authors.forename: H S
authors.initials: HS
authors.lastname: Silva
authors.forename: M L
authors.initials: ML
authors.lastname: Martins
authors.forename: M J
authors.initials: MJ
authors.lastname: Vilela
authors.forename: Ruy
authors.initials: R
authors.lastname: Jaeger
authors.forename: B
authors.initials: B
authors.lastname: Kachar
mesh_terms: D000663:Amphibians; D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D002460:Cell Line; D002462:Cell Membrane / Q000502:physiology*; D003198:Computer Simulation; D004847:Epithelial Cells / Q000502:physiology*; D006112:Gravitation; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D008560:Membrane Fluidity / Q000502:physiology*; D008954:Models, Biological; D015233:Models, Statistical; D009068:Movement / Q000502:physiology; D013269:Stochastic Processes