title: Anomalies in the motion dynamics of long-flagella mutants of Chlamydomonas reinhardtii.
abstract: Chlamydomonas reinhardtii has long been used as a model organism in studies of cell motility and flagellar dynamics. The motility of the well-conserved '9+2' axoneme in its flagella remains a subject of immense curiosity. Using high-speed videography and morphological analyses, we have characterized long-flagella mutants (lf1, lf2-1, lf2-5, lf3-2, and lf4) of C. reinhardtii for biophysical parameters such as swimming velocities, waveforms, beat frequencies, and swimming trajectories. These mutants are aberrant in proteins involved in the regulation of flagellar length and bring about a phenotypic increase in this length. Our results reveal that the flagellar beat frequency and swimming velocity are negatively correlated with the length of the flagella. When compared to the wild-type, any increase in the flagellar length reduces both the swimming velocities (by 26-57%) and beat frequencies (by 8-16%). We demonstrate that with no apparent aberrations/ultrastructural deformities in the mutant axonemes, it is this increased length that has a critical role to play in the motion dynamics of C. reinhardtii cells, and, provided there are no significant changes in their flagellar proteome, any increase in this length compromises the swimming velocity either by reduction of the beat frequency or by an alteration in the waveform of the flagella.
authors.affiliation: UM-DAE-Centre for Excellence in Basic Sciences, Biological Sciences, Kalina campus, Santacruz (E), Mumbai, 400 098, India.
authors.forename: Dolly K
authors.initials: DK
authors.lastname: Khona
authors.forename: Venkatramanan G
authors.initials: VG
authors.lastname: Rao
authors.forename: Mustafa J
authors.initials: MJ
authors.lastname: Motiwalla
authors.forename: P C Sreekrishna
authors.initials: PC
authors.lastname: Varma
authors.forename: Anisha R
authors.initials: AR
authors.lastname: Kashyap
authors.forename: Koyel
authors.initials: K
authors.lastname: Das
authors.forename: Seema M
authors.initials: SM
authors.lastname: Shirolikar
authors.forename: Lalit
authors.initials: L
authors.lastname: Borde
authors.forename: Jayashree A
authors.initials: JA
authors.lastname: Dharmadhikari
authors.forename: Aditya K
authors.initials: AK
authors.lastname: Dharmadhikari
authors.forename: Siuli
authors.initials: S
authors.lastname: Mukhopadhyay
authors.forename: Deepak
authors.initials: D
authors.lastname: Mathur
authors.forename: Jacinta S
authors.initials: JS
authors.lastname: D'Souza
mesh_terms: D016825:Chlamydomonas reinhardtii / Q000166:cytology* / Q000235:genetics* / Q000378:metabolism; D004398:Dyneins / Q000378:metabolism; D005407:Flagella / Q000378:metabolism*; D009068:Movement; D009154:Mutation
chemical_list: D004398:Dyneins