Axenic growth of Giardia lamblia in Diamond's TPS-1 medium.

A strain of Giardia lamblia was gradually adapted to grow in Diamond's TPS-1 medium. The parasites grew luxuriantly and formed a monolayer on the surface of the culture vessels. When G. lamblia was inoculated into fresh medium, the population of the parasites grew from 22,000 cells/ml to peak numbers of 2.1 X 10(6)/ml in six days with a generation time of 12.2 hours at 37 degrees C. After a few days of incubation a sediment could be seen at the bottom of the tubes which contained a multitude of free-swimming Giardia as well as clumps of them. The sediment sometimes also contained many rings of Giardia. The rings were usually associated with dead Giardia cells containing a large bubble. Two, three and sometimes as many as six Giardia were seen surrounding the bubble. The bubble probably provides additional surface area to which the Giardia may attach.