Synchronized swimming of algae

Jul 23, 2009

Using high-speed cinematography, scientists at Cambridge University have discovered that individual algal cells can regulate the beating of their flagella in and out of synchrony in a manner that controls their swimming trajectories. Their research was published on the 24th July in the journal Science.

The researchers studied the unicellular organism Chlamydomonas reinhardtii, which has two hair-like appendages known as flagella. The beating of flagella propels Chlamydomonas through the fluid and simultaneously makes it spin about an axis.

The researchers found that cells can beat their flagella in two fundamentally distinct modes: synchronised, with nearly identical frequencies and positions, and unsynchronised, with two rather different frequencies. Using a specialised apparatus to track the swimming trajectories of individual cells, the group showed that the periods of synchrony correspond to nearly straight-line motion, while sharp turns result from the asynchronous beating. Whereas previous studies had suggested that these modes were associated with different subpopulations of cells, the new work shows that the cells actually control the frequencies and thereby switch back and forth between the two modes. In essence, this suggests Chlamydomonas has two 'gears'.

Moreover, the researchers have developed a that describes the two beating flagella as "coupled oscillators," in a way similar to models of synchronised flashing of fireflies and the "Mexican wave" of people in a stadium. Analyzing terabytes of data on the patterns of synchronisation, they showed that the strength of the coupling was consistent with it arising from the fluid flows set up by the beating flagella. These observations constitute the first direct demonstration that hydrodynamic interactions are responsible for synchronisation, which has long been predicted to lead to such coordination.

Professor Raymond E. Goldstein, the Schlumberger Professor of Complex Physical Systems in the Department of Applied Mathematics and Theoretical Physics (DAMTP) and lead author of the study, said: "These results indicate that flagellar synchronization is a much more complex problem than had been appreciated, and involves a delicate interplay of cellular regulation, hydrodynamics, and biochemical noise."

Funded by the Biotechnology and Biological Sciences Research Council (BBSRC), the work is part of a larger effort to improve our knowledge of evolutionary transitions from single-cell organisms (like Chlamydomonas) to multicellular ones. In addition, the flagella of Chlamydomonas cells are nearly identical to the cilia in the human body. In many of life's processes, from reproduction to respiration, coordinated action of cilia plays a crucial role. For this reason, insight into synchronization and its control may have significant implications for human health and disease.

More information: The article 'Chlamydomonas swims with two `gears' in a eukaryotic version of run-and-tumble locomotion' was published Friday 24th July in the journal Science.

Source: University of Cambridge (news : web)

Explore further: Researchers film protein quake for the first time

add to favorites email to friend print save as pdf

Related Stories

Bacteria Take the Path of Least Resistance

Jul 01, 2005

Findings may lead to new nano-devices and understanding of infection Researchers have reported new information about how certain bacteria propel themselves from one place to another. Insight into bacteria ...

Mixing it up with E. coli

Jan 15, 2007

Poetry in motion may seem like an odd way to describe swimming bacteria, but that's what researchers at Drexel University got when they enlisted Escherichia coli (E. coli) in an effort to tackle a major problem in developing ...

Scientists Sequence Genome of Soil-Dwelling Green Alga

Oct 11, 2007

The genome analysis of a tiny green alga has uncovered hundreds of genes that are uniquely associated with carbon dioxide capture and generation of biomass. Among the 15,000-plus genes revealed in the study ...

Algae Provide New Clues to Cancer

Oct 13, 2006

A microscopic green alga helped scientists at the Salk Institute for Biological Studies identify a novel function for the retinoblastoma protein (RB), which is known for its role as a tumor suppressor in mammalian ...

Unicellular microRNA discovery

Apr 30, 2007

In the May 15th issue of Genes & Development, an international collaboration of researchers, led by Dr. Yijun Qi (National Institute of Biological Sciences, China), report on their discovery of microRNAs in the unicellular green ...

Recommended for you

Researchers film protein quake for the first time

6 hours ago

One of nature's mysteries is how plants survive impact by the huge amounts of energy contained in the sun's rays, while using this energy for photosynthesis. The hypothesis is that the light-absorbing proteins ...

Deploying exosomes to win a battle of the sexes

Aug 25, 2014

There are many biological tools that help animals ensure reproductive success. A new study in The Journal of Cell Biology provides further detail into how one such mechanism enables male fruit flies to imp ...

User comments : 0