Cytoskeleton fluorescent probes

A sample purified of an Ostreopsis ovata extract was lately assayed on actin cytoskeleton of isolated rabbit intestinal cells by Botana s group. The measure of a fluorescent dye bound specifically to actin filaments (Oregon green 514-phalloidin) showed that Ostreopsis ovata toxin also interfered the cytoskeleton as occurred in the two previous cases (Table 6.4). In addition, activity on membrane potential of neuroblastoma cells was studied through the fluorescent probe bis-oxonol. The purified extract displayed a depolarizing effect (the value of relative fluorescence obtained at 350 seconds for cells exposed to the sample was 1.49 0.12 versus control) also similar to palytoxin and ostreocin-D. Therefore, although these studies only shed very preliminary information abont the toxic compound produced by Ostreopsis ovata, they appear to point out some link between its cellular targets and those identified for palytoxin and ostreocin-D in these studies. 

The cytoskeleton is a cellular scaffold within the cytoplasm of the cell or within structures such as flagella, cilia, and lamellipodia. The cytoskeleton plays a crucial role in cellular integrity/structural support, cell division, cell motility, and intracellular transport. Staining of the cytoskeleton may be achieved by immunofluorescence in fixed cells however there are also dyes available, such as fluorescently labelled phalloidin, which directly labels actin filaments, as well as tubulin tracker which labels microtubules (Molecular Probes). Phalloidin is poorly permeable to living cells however, phalloidin derivatives with improved permeability properties are also available. Although both phalloidin derivatives and microtubule tracker can be used in live cells, it should be noted that both dyes are toxic as they inhibit cell division, and therefore limits their applications. 

Evangelio JA, Abal M, Barasoain I, Souto AA, Lillo MP, Acuna AU, Amat-Guerri F, Andreu JM (1998) Fluorescent Taxoids as Probes of the Microtubule Cytoskeleton. Cell Motility and the Cytoskeleton 39 73... 

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