Protozoans are single-cell eukaryotes and many of the best studied protozoans are parasitic to humans (e.g.,Plasmodium falciparumcausing malaria andTrypanosoma bruceicausing sleeping sickness). These organisms are distantly related to humans but with retained eukaryotic type of cellular processes, making them good model systems for studies of the evolution of basic processes like the cell cycle.Giardia intestinaliscauses 250 million cases of diarrhea yearly and is one of the earliest diverging protozoans. It has recently been possible to synchronize its cell cycle using compounds that inhibit different steps of the cell cycle and the detailed protocol is described here.
