Comparative studies of the actin cytoskeleton response to maitotoxin and okadaic acid.

The specific cytotoxic effects of phycotoxins on BHK 21 C13 fibroblasts in culture were studied with maitotoxin (MTX), okadaic acid (OA) and crude extracts from Gambierdiscus toxicus Adachi and Fukuyo and Prorocentrum lima Ehrenberg. These dinoflagellates produce MTX and OA respectively. MTX and G.

Differential effects of maitotoxin on calcium entry and ciliary beating in the rabbit ciliated tracheal epithelium.

The marine toxin maitotoxin (MTX) induces stimulation of ciliary beating in primary cultures of rabbit tracheal epithelial cells. The response is time- and concentration-dependent. External calcium is an absolute requirement, although at a very low concentration (50 microM for maximal effect).

Modulation of fibroblast response to maitotoxin along the cell division cycle.

Maitotoxin (MTX) induces an increase of [Ca2+]i and of phosphoinositide breakdown in various cell types. The [Ca2+]i increase followed with fluorescent probes on cell suspensions has been described as slow and lasting, in contrast to the "signal" induced by calcium ionophores such as ionomycin. MTX effects have been studied on two fibroblastic cell lines, BHK21 C13 and FR 3T3, synchronized by serum deprivation treatment performed in an isoleucine-free medium for BHK21 C13 cells.

Cytotoxic quantification of maitotoxin-like activity from the dinoflagellate Gambierdiscus toxicus.

Gambierdiscus toxicus is a marine dinoflagellate involved in the food-borne disease ciguatera. Its toxicity is mainly due to maitotoxin, a hydrophilic toxin, the chemical structure of which has recently been described. This toxin increases internal Ca(2+) concentration and triggers phosphoinositide breakdown.

Selection of cytotoxic responses to maitotoxin and okadaic acid and evaluation of toxicity of dinoflagellate extracts.

The cytotoxicity of maitotoxin (MTX) and okadaic acid (OA) was studied on three mammalian fibroblast cell lines. Neutral red uptake (NRU), which measures cell viability, and morphological alterations were selected as rapid suitable responses. NRU allowed a precise toxicity quantification while the observations of morphological damage revealed differences specific to MTX (cell blebbing) and OA (cell rounding).