THE MEASUREMENT OF SWIMMING VELOCITY OF VIBRIO-CHOLERAE AND PSEUDOMONAS-AERUGINOSA USING THE VIDEO TRACKING METHOD

The swimming velocities of two monotrichous flagellated bacteria were measured by a computer-assisted video tracking method. Tracing the mov ing path of the individual bacterium revealed that the bacterial cell did not swim continuously in a straight direction, but frequently chan ged swimming direction and velocity. The average swimming velocities c alculated from the 3-sec path were 75.4 +/- 9.4 mu m/sec in four strai ns of Vibrio cholerae and 51.3 +/- 8.4 mu m/sec in five strains of Pse udomonas aeruginosa. These results suggest that V. cholerae swim faste r than P. aeruginosa at 30 C in nutrient broth. This method is useful for a detailed analysis of bacterial movement and moving patterns in d ifferent environmental conditions.