Evidence for intercellular cohesion in the septate junction of the protozoon Gregarina

Injection of Lucifer Yellow dye was used to establish whether septate junctions formed a permeability barrier between primite and satellite gamonts in the syzygy of the protozoon Gregarina. The fluorescent dye did not pass from one cell to the other, thus suggesting that the septate junction served only for mechanical adhesion. Later on in development, when the gametocyst had formed, the septate junction vanished and interruptions were observed between opposing cell membranes. At this stage the fluorescent dye was able to pass freely into the conjugated cells.