Inducement of wound motility in intact giant algal cells.

The cytoplasm (with its organelles) of intact cells of Ernodesmis verticillata (Chlorophyta) can be induced to contract in the presence of calcium ionophores and phenothiazine antipsychotics. The cell contents mimic wound-healing contraction if a combination of 10 microM A23187 and 10 microM chlorpromazine (or trifluoperazine) is present in a Ca2+-containing medium. The average incubation time is approx. 50 min for contraction. It is imperative that only fresh solutions of ionophores and phenothiazines are used, because stock solutions only 3 h old virtually double the response time of these cells. Separately, neither the ionophore nor the phenothiazines will induce contraction. The addition of 1.0 mM La3+ completely prevents induction of motility. With trifluoperazine, equimolar X-537A will substitute for A23187, but it takes three times as long to induce contraction. Motility cannot be induced in Ca2+-free media (containing 5.0 mM EGTA). It therefore appears that Ca2+ fluxes are responsible for triggering wound contraction in these giant algal cells. An influx of calcium ions from the external medium is suggested as being at least partially involved.