title: Propulsion of African trypanosomes is driven by bihelical waves with alternating chirality separated by kinks.
abstract: Trypanosoma brucei, a parasitic protist with a single flagellum, is the causative agent of African sleeping sickness. Propulsion of T. brucei was long believed to be by a drill-like, helical motion. Using millisecond differential interference-contrast microscopy and analyzing image sequences of cultured procyclic-form and bloodstream-form parasites, as well as bloodstream-form cells in infected mouse blood, we find that, instead, motility of T. brucei is by the propagation of kinks, separating left-handed and right-handed helical waves. Kink-driven motility, previously encountered in prokaryotes, permits T. brucei a helical propagation mechanism while avoiding the large viscous drag associated with a net rotation of the broad end of its tapering body. Our study demonstrates that millisecond differential interference-contrast microscopy can be a useful tool for uncovering important short-time features of microorganism locomotion.
authors.affiliation: Department of Surgery, Division of Surgical Oncology, Molecular Biology Institute, The David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Rodríguez
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Lopez
authors.forename: Michelle C
authors.initials: MC
authors.lastname: Thayer
authors.forename: Yunzhe
authors.initials: Y
authors.lastname: Zhao
authors.forename: Michael
authors.initials: M
authors.lastname: Oberholzer
authors.forename: Donald D
authors.initials: DD
authors.lastname: Chang
authors.forename: Neville K
authors.initials: NK
authors.lastname: Kisalu
authors.forename: Manuel L
authors.initials: ML
authors.lastname: Penichet
authors.forename: Gustavo
authors.initials: G
authors.lastname: Helguera
authors.forename: Robijn
authors.initials: R
authors.lastname: Bruinsma
authors.forename: Kent L
authors.initials: KL
authors.lastname: Hill
authors.forename: Jianwei
authors.initials: J
authors.lastname: Miao
mesh_terms: D000818:Animals; D002465:Cell Movement; D002478:Cells, Cultured; D005407:Flagella / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008853:Microscopy / Q000379:methods; D014346:Trypanosoma brucei brucei / Q000166:cytology / Q000502:physiology*; D014353:Trypanosomiasis, African / Q000382:microbiology*