The Disruption of Dictyosome Structure, Polarity and Secretory Activity in the Scale-producing Green Alga, Pyramimonas inconstans

Domozych, D. S. and Korbusieski, T. J. 1985. The disruptionof dictyosome structure, polarity and secretory activity inthe scale-producing green alga Pyramimonas inconstans.—J.exp.Bot.36: 1304–1312. Dictyosome morphology and scale morphogenesis in the green alga,Pyramimonas inconstans, are well-defined ultrastructurally.By applying the sodium-specific ionophore, monensin, to actively-growingcell cultures, both dictyosome micro-architecture and the scale-basedsecretory pathway can be significantly altered. Applicationof 0.1 mol m³ and 0.01 mol m ^–3monensin for short periods(1 -3 h) results in cisternal curling and the disorientationof dictyosome polarity. Prolonged exposure to the ionophore(4-24 h) results in the complete disruption of dictyosome morphologyand scale morphogenesis with the emergence of irregular vesiclesfrom the maturing face. Removal of monensin by repeated washingreturns dictyosome structure and secretory activity to normal.These results indicate that Golgi apparatus integrity and secretoryactivity in Pyramimonas may be controlled by a localized, cytoplasmicproton gradient Key words: Monensin, Pyramimonas, dictyosome