Table 2. Quantification of movement type of live gliding parasites on FBS or Collagen I.

Live parasites of the indicated strain were allowed to glide on substrate coated dishes and gliding modalities were enumerated by observing individual parasites as described in Experimental procedures. The different forms of motility of the Δsub1::ΔGPISUB1 strain could not be reliably assessed on FBS since, rather than actively gliding on the substrate, the parasites frequently moved in the direction of the media flow of the heating element used during the video capture. Parasites that are actively gliding can go against the direction of this flow, and thus Δsub1::FLSUB1 on FBS and collagen, and the Δsub1 and Δsub1::ΔGPISUB1 on collagen (and even the Δsub1 on FBS, those few that did glide) could be scored. The Δsub1::ΔGPISUB1 on FBS moved mostly in one direction, although they were able to glide circularly against the flow. The weak adhesion of the Δsub1::ΔGPISUB1 parasites may make them more susceptible to transient attachment and displacement in media compared to Δsub1 parasites, complicating enumeration of the different gliding modes. ND-not determined.

Parasite Strain (on FBS) (on Collagen)	Helical % FBS % Collagen	Twirling % FBS % Collagen	Circular % FBS % Collagen	Inactive % FBS % Collagen	Non-Productive % FBS % Collagen
Δsub1:: FLSUB1
(211 parasites)	33.2%	17.1%	14.7%	20.0%	15.2%
(128 parasites)	38.2%	21.9%	3.1%	23.4%	13.3%
Δsub1
(190 parasites)	4.7%	15.3%	8.9%	54.0%	17.4%
(181 parasites)	23.2%	19.3%	1.1%	40.8%	15.5%
Δsub1::ΔGPISUB1
(205 parasites)	ND	ND	ND	ND	ND
(180 parasites)	42.7%	9.4%	1.7%	32.2%	13.9%