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Dr. Richard Bräucker

Analysis of swimming behaviour

Please note: you will find more informations about the items marked green in the glossar.

  

Examples of superimposed images of swimming tracks of Didinium nasutum.
The cells moved under natural gravity in the vertical plane. The time course is documented by 14 different colours (Start: red, end: grey).
Time of superimposition: 2.7s; the median swimming rate of the cells is about 1.6 mm/s.

Click the image to see an animation (69 kByte)

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Swimming tracks of Paramecium caudatum compared to the image above the time resolution has been considerably increased (256 colours represent the data points; start red, end pink). Recording time:  about 6s; swimming rates: about 680 µm/s. Note the  "kinks" in some tracks, reflecting "reversals" (sudden changes in  swimming direction). Some tracks show a sinusoidal course (which represents the projection of the helical movement).

Click the image to see an animation (44 kByte)

 

Typical polarographic representations of the swimming behaviour of Didinium nasutum in a vertical experimental vessel under natural gravity conditions. The left polarogramm illustrates that the majority of the cells was moving upward. (More than 38% of the cells moved upward with an angular deviation less than 22°; "negative gravitaxis") 

The right polarogramm shows median swimming rates as a function of cell orientation. Downwards swimming cells move faster than upwards or horizontally swimming cells. However, the velocity difference cannot be explained by sedimentation rate alone (refer gravikinesis).

 

Home Gravikinesis Swimming tracks Microgravity Ciliates

Last update: 28.12.2003