Con A Binds to the Membranellar and Somatic Cilia of Stentor and to the Developing Oral Primordium During Oral Regeneration1

Abstract

ABSTRACTBinding sites for Concanavalin A have been located in the ciliate Stentor coeruleus by utilizing FITC‐Con A and fluorescence microscopy. When both nonregenerating and regenerating Stentor are fixed prior to FITC‐Con A exposure, FITC‐Con A binds intensely to the cilia of the membranellar band and to the somatic cilia that cover much of the cell surface. No binding is observed between the ciliary rows. The FITC‐Con A also binds to the developing oral primordia of regenerating cells. Binding of FITC‐Con A in the early stages of regeneration (prior to stage 4) appears to be less intense than that in the later stages. Additional FITC‐Con A binding appeared as a granular fluorescence in the area of the developing buccal cavity beginning at about stage 4 and disappearing around stages 6–7. The presence of α‐D‐methyl mannoside prevented the binding of FITC‐Con A to either regenerating or nonregenerating cells. If nonregenerating Stentor are exposed to FITC‐Con A prior to fixation, the binding pattern is entirely different with the fluorescence primarily in the form of random, granular patches spread over much of the cell but with no binding to either type of cilia. These results demonstrate that membrane glycoproteins capable of binding Con A are located primarily in the membranellar and somatic cilia and in the developing oral primordia during oral regeneration in Stentor. Concanavalin A binding to these sites may be involved in the Con A‐induced inhibition of oral regeneration observed in earlier studies.