Lipids trigger changes in the elasticity of the cytoskeleton in plant cells: a cell optical displacement assay for live cell measurements.

Abstract

Abstract. An assay has been developed to quantitatively measure the tension and elasticity of the cytoskeleton in living plant cells. The cell optical displacement assay (CODA) uses a focused laser beam to optically trap and displace transvacuolar and cortical strands through a defined distance within the cell. Results from these experiments provide evidence for the classification of at least two rheologically distinct cytoskeletal assemblies, cortical and transvacuolar, that differ in their tension and response to both signaling molecules and reagents that perturb the cytoskeleton. It is further demonstrated that the tension of the transvacuolar strands can be significantly decreased by the addition of either linoleic acid, 1,2 dioctanoylsn-glycerol, or 1,3 dioctanoylglycerol. These decreases in tension could also be induced by lowering the cytoplasmic pH. In contrast, addition of Ca 2+, Mg 2+, or the ionophore A23187 to the cells caused a considerable increase in the tension of the transvacuolar strands. The data provides evidence that: (a) linoleic acid may be a signaling molecule in plant cells; (b) diacylglycerol functions as a signaling molecule through a protein kinase C-independent pathway mediated by PLA2; and (c) Ca 2+ and pH have regulatory roles for controlling cytoskeleton tension and organization.

Aluminum Induces Rigor within the Actin Network of Soybean Cells

“…Cells were permeabilized and stained with Bodipy-phallacidin (F-actin-specific fluorescent probe) (Molecular Probes, Eugene, OR) as described (Grabski et al, 1994). A total of 25 sections (at 0.5-pm intervals) were accumulated and examined.…”

“…CODA was performed as described by Grabski et al (1994) and Schindler (1995). Briefly, a soybean (Glycine max [L.] Merr.…”

“…A total of 25 sections (at 0.5-pm intervals) were accumulated and examined. An InSight Bilateral Laser Scanning Confocal Microscope (Meridian Instruments) was utilized as described (Grabski et al, 1994).…”

Identification and Characterization of Linoleic Acid as an Endogenous Modulator of in Vitro N-1-Naphthylphthalamic Acid Binding

“…Both linoleic and linolenic acids stimulate the abscission of bean petiole explants (Ueda et al, 1991). Recently, it has been shown that treatments of soybean cells with linoleic acid results in pronounced changes in cytoskeletal organization (Grabski et al, 1994). In vitro, free fatty acids elicit a number of effects.…”

Changes in Hechtian Strands in Cold-Hardened Cells Measured by Optical Microsurgery

“…Optical tweezers use laser light to produce non-contact forces in the piconewton range, and are capable of positioning small particles with submicrometer accuracy (for reviews, see Svoboda and Block, 1994;Hoffmann, 1996;Sheetz, 1998). Intracellular forces have previously been indirectly measured using organelles trapped in a focused laser beam (Ashkin and Dziedzic, 1989;Grabski et al, 1994;Schindler, 1995;Felgner et al, 1996), but the force was not calibrated.…”