Neodymium cations Nd3+ were transported to the interior ofEuglena gracilis 277

Euglena gracilis 277, a unicellular green alga, demonstrated remarkable ability to transport Nd3+ to the cell compartments. For a given amount of Nd3+ and cells, the results of ICP-AES indicated that the cellular uptake of Nd3+ was independent of Nd3+ concentration in the bulk solution. The average uptake of Nd3+ per cell (mNd) is proportional to a parameter ξ — the ratio of neodymium content to the cell counts of the system. A novel approach for probing cellular neodymium by tetraiodotetra chlorofluorescein (I4TCF) has been devised. Data derived from the cryosections of I4TCF-Nd3+ stained cells and EDAX of the fast freezing ultrathin cryosections indicate that Nd3+ is distributed over the cell compartments. Chloroplasts are the major compartments as the residence of Nd3+ in the alga. The transport should be against a concentration gradient of Nd3+ on the order of five, even higher. It is proposed that a calcium ion channel would play an important role in the Nd3+ transportation.