Ref ID : 4945
Tom Fenchel; Orientation in two dimensions: chemosensory motile behaviour of Euplotes vannus. Europ.J.Protistol. 40:49-55, 2004
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Notes : Most studies on chemosensory motile behaviour of protists apply to free-swimming species moving in 3-dimensional space. But many protists are associated with surfaces and this excludes the use of helical klinotaxis for orientation in chemical gradients. It is here shown that the predominantly surface-dwelling ciliated protozoon Euplotes vannus orients itself in chemical gradient by simple temporal gradient sensing (equivalent to the run and tumble mechanism described for bacteria) and they react only to a temporal decrease in attractant concentration. The motility of Euplotes can be described as a classical 2-dimensional random walk with Poisson distribution of run lengths punctuated by random changes in walking direction. The chemosensory motile behaviour allows cells that are distributed within about 1 cm2 to accumulate at point sources of an attractant with in 3-4 min.