Individual flagellar waveform affects collective behavior of Chlamydomonas reinhardtii

Azusa Kage, Yoshihiro Mogami

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Bioconvection is a form of collective motion that occurs spontaneously in the suspension of swimming microorganisms. In a previous study, we quantitatively described the "pattern transition," a phase transition phenomenon that so far has exclusively been observed in bioconvection of the unicellular green alga Chlamydomonas. We suggested that the transition could be induced by changes in the balance between the gravitational and shear-induced torques, both of which act to determine the orientation of the organism in the shear flow. As both of the torques should be affected by the geometry of the Chlamydomonas cell, alteration in the flagellar waveform might change the extent of torque generation by altering overall geometry of the cell. Based on this working hypothesis, we examined bioconvection behavior of two flagellar mutants of Chlamydomonas reinhardtii, ida1 and oda2, making reference to the wild type. Flagella of ida1 beat with an abnormal waveform, while flagella of oda2 show a normal waveform but lower beat frequency. As a result, both mutants had swimming speed of less than 50% of the wild type. ida1 formed bioconvection patterns with smaller spacing than those of wild type and oda2. Two-axis view revealed the periodic movement of the settling blobs of ida1, while oda2 showed qualitatively similar behavior to that of wild type. Unexpectedly, ida1 showed stronger negative gravitaxis than did wild type, while oda2 showed relatively weak gravitaxis. These findings suggest that flagellar waveform, not swimming speed or beat frequency, strongly affect bioconvection behavior in C. reinhardtii.

Original languageEnglish
Pages (from-to)396-404
Number of pages9
JournalZoological Science
Volume32
Issue number4
DOIs
Publication statusPublished - 2015 Aug 1

Keywords

  • bioconvection
  • collective motion
  • eukaryotic flagella
  • gravitaxis
  • gyrotaxis

ASJC Scopus subject areas

  • Animal Science and Zoology

Fingerprint Dive into the research topics of 'Individual flagellar waveform affects collective behavior of Chlamydomonas reinhardtii'. Together they form a unique fingerprint.

Cite this