MECHANISM OF STRONTIUM UPTAKE AND TRANSPORT IN NEUROSPORA CRASSA

Anupama M., Ashok Kumar K., and Naveena Lavanya Latha J.

ABSTRACT

Strontium uptake and sub cellular compartmentation were investigated in the model filamentous fungus Neurospora crassa. Sr2+ uptake by the mycelium was found to be a function of time involving three compartments corresponding in series to cell wall (52%), cytoplasm (19%) and vacuole (25%), when mycelia were exposed to a 10 mM Sr2+ concentration. At 4 ˚C, and in alkali killed biomass only ~50% of the Sr2+ taken up by the mycelia was recovered in cell wall-bound fraction, suggesting it is a metabolically mediated process. Inhibitors of IP3 pathway and CaM pathway inhibited Sr2+ accumulation in N.crassa mycelia by up to 88%. Sr2+ uptake into cytoplasm is through the Ca2+ transporters. Binding of Sr2+ onto cell walls, accumulation of into the cell and displacement of calcium by strontium reveals the ability of the organism to substantiate Ca2+ by Sr2+. These data represent a first step towards the understanding role of Sr2+ as a substituent in place of Ca2+ in fungi.

Keywords: Sr2+ uptake, Sr2+ transport, cell wall bound, filamentous fungi, Neurospora crassa.