An electro-optic monitor of the behavior of Chlamydomonas reinhardtii cilia

Keith Josef, Jureepan Saranak, Kenneth W. Foster

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


The unicellular green alga Chlamydomonas reinhardtii steers through water with a pair of cilia (eukaryotic flagella). Long-term observation of the beating of its cilia with controlled stimulation is improving our understanding of how a cell responds to sensory inputs. Here we describe how to record ciliary motion continuously for long periods. We also report experiments on the network of intracellular signaling that connects the environment inputs with response outputs. Local spatial changes in ciliary response on the time scale of the underlying biochemical dynamics are observed. Near-infrared light monitors the cells held by a micropipette. This condition is tolerated well for hours, not interfering with ciliary beating or sensory transduction. A computer integrates the light stimulation of the eye of Chlamydomonas with the ciliary motion making possible long-term correlations. Measures of ciliary responses include the beating frequency, stroke velocity, and stroke duration of each cilium, and the relative phase of the cis and trans cilia. The stationarity and dependence of the system on light intensity was investigated. About 150,000,000 total beat cycles and up to 8 h on one cell have been recorded. Each beat cycle is resolved so that each asynchronous beat is detected. Responses extend only a few hundred milliseconds, but there is a persistence of momentary changes that last much longer. Interestingly, we see a response that is linear with absolute light intensity as well as different kinds of response that are clearly non-linear, implying two signaling pathways from the cell body to the cilia.

Original languageEnglish (US)
Pages (from-to)83-96
Number of pages14
JournalCell Motility and the Cytoskeleton
Issue number2
StatePublished - Jun 2005


  • Eukaryotic flagella
  • Motility
  • Nonlinear dynamic network
  • Phototaxis
  • Signal integration

ASJC Scopus subject areas

  • Structural Biology
  • Cell Biology


Dive into the research topics of 'An electro-optic monitor of the behavior of Chlamydomonas reinhardtii cilia'. Together they form a unique fingerprint.

Cite this