The sulphation inhibitor sodium selenate arrests the growth ofDictyostelium discoideum

Abstract

Sulphate incorporation into glycopeptides appears to be a key event in the development of a number of organisms. An inhibitor of sulphation, sodium selenate, has been used in this study to examine the possibility that sulphation has a comparable role in the development of Dictyostelium discoideum. At concentrations of 0.1 mM and 1.0 mM, exogenously supplied selenate reversibly arrested the growth of bacterially grown amoebae of D. discoideum. In contrast, the effect of selenate on development was minimal. In the presence of 1.0 mM selenate, aggregation and tip formation were delayed 2–3 h and aggregates were slightly smaller; exogenous 0.1 mM selenate had no visible effect on development. However, the possibility that starved amoebae are impermeable to selenate was not excluded. The vegetative growth and development of an axenic strain in the presence of selenate closely resembled that of the bacterially grown strain. Since an inhibitory effect of 1.0 mM selenate on [35S]sulphate incorporation into acetone precipitable protein was also demonstrated, these results suggest that sulphation is necessary for the growth of D. discoideum.