Georgia Journal of Science


In amoeboid cells, food particles are engulfed only after receptors on the phagocytic cell’s membrane bind to ligands on a particle’s surface. Ciliates also feed via phagocytosis but, instead of enveloping particles, some ciliates take them up through a complex, permanent, funnel-shaped, feeding apparatus. It is unclear whether receptor-ligand interactions are needed to trigger the process. If ciliates were shown to feed selectively on certain particles over others, based on the particles’ surface properties, then receptor-ligand interactions would likely play a role in phagocytosis. The literature includes few reports of such selectivity. To further investigate this issue, we chose to study feeding preference in the ciliate Tetrahymena pyriformis. We fed Tetrahymena mixtures of orange and green, fluorescent, 3 µm, polystyrene beads at two concentrations. One of the two types of beads was coated with bovine serum albumin. Authors were blinded to experimental conditions. We found no evidence of a preference for coated or uncoated beads at either concentration. We also found no trend toward the development of selective feeding as cells acquired more beads over time. Although we cannot rule out the possibility that Tetrahymena feeds selectively, we did not find convincing evidence of such selectivity when T. pyriformis is given a choice between uncoated beads and those coated with albumin. Our results failed to demonstrate a role for molecular recognition when Tetrahymena engages in phagocytosis.


Funded by UNG’s Department of Biology and Center for Undergraduate Research and Creative Activities. Frank Corotto, the journal’s associate editor, was not involved in the editorial review or decision to publish this article.