Attachment of <i>Giardia</i> - A Hydrodynamic Model Based on Flagellar Activity

Abstract

ABSTRACT The attachment of Giardia trophozoites can be modelled by viscous-flow equations demonstrating that a suction pressure arises from the viscous stress of a fluid flow led beneath the cell by flagellar activity. Changing fluid velocity is less significant in generating suction. Over the range of flagellar wave parameters observed from cells attached to glass, suction pressure may reach io2 dynes cm-2. Expressions for the bending of a thick disc under normal load allow an estimate of suction pressure in situ from its deforming effect on the gut-cell cortex. Allowing for alternative boundary states, calculations suggest that suction pressures close to 102 dynes cm-2 account for the deformations measured from electron micrographs. The shape assumed by a ventro-lateral flange determines the magnitude of the developed suction pressure and may constitute a control mechanism of attachment and detachment.