Flagellar adhesion ofCrithidia fasciculata to Millipore filters

Summary

Millipore filters composed of mixed cellulose esters have been used to investigate the adhesion of flagella ofCrithidia fasciculata to a non-living substrate. After 4 days on the surface of a culture of the flagellate, one side of the filter was covered with a monolayer of cells. In most cases the flagella penetrated the pores of the filter and at one or more points along their length presumed sites of adhesion were marked by the presence of hemidesmosomes, characterized by a thickened inner leaflet of the flagellar membrane and the presence of large numbers of fine filaments. If the interstitial space of the filter was sufficiently large, the hemidesmosomes occurred at the apex of an evagination of the flagellar membrane. These evaginations are believed to arise by movement of the flagellum relative to the point of adhesion. The addition of distilled water causes de-adhesion of the flagellum and its withdrawal from the filter. The hypothesis that cells adhere to one another and to non-living substrates by different mechanisms is discussed in the light of the results obtained here.