Uptake of Lanthanum by a Yeast

Abstract

IN the course of studies of the barium metabolism of larval Drosophila which it is planned to report in full elsewhere, we have found that larvæ on a medium containing barium-140 showed lanthanum-140 enrichment if the medium had been inoculated with Texas Y-2 strain of yeast¹ twenty-four hours before adding the larvæ, but barium-140 enrichment if the larvæ had been placed directly on the sterile food. These enrichments were measured by means of deviations in the shape of the curves of radioactive decay for the chain ¹⁴⁰Ba → ¹⁴⁰La → ¹⁴⁰Ce, as has been clearly described² for the strontium-90–yttrium-90 chain. The observation appeared explicable on the assumption that the yeast cells were selecting lanthanum from the medium, while the larvæ, though preferring to feed on yeast cells, preferentially absorb barium.