Flagellar adhesion and deadhesion in Chlamydomonas gametes: effects of tunicamycin and observations on flagellar tip morphology.

The aggregation-dependent loss of flagellar adhesiveness in chlamydomonas reinhardi has been correlated with changes in flagellar tip morphology during adhesion and deadhesion. As aggregating mt- and impotent (able to adhere, but not fuse) mt+ gametes begin to disaggregate in the presence of the protein synthesis inhibitor cycloheximide, there is a concomitant change in flagellar tip morphology from the activated bulbous form to the nonactivated tapered shape. the requirement of protein-synthetic activity for the maintenance of flagellar adhesiveness during aggregation may be due in part to turnover of proteins involved in formation or stabilization of activated flagellar tips. Incubation of aggregating gametes with tunicamycin indicates that, like protein synthesis inhibitors, this inhibitor of glycosylation also causes adhering gametes to deadhere. The results suggest that protein glycosylation may be essential for maintenance of adhesiveness during aggregation.