TABLE 1.

Motility parameters.

Temperature (°C)	Fraction of cells motile ± SD	Total # tracks analyzed (# replicates)	# fast runs/tumbles/helices/circles	Mean ± SD speed (μm/s) (range)	Mean ± SD acceleration (μm/s2)	Mean ± SD displacement (μm/s) (range)
28	20 ± 1	36 (2)	10/8/10/8	16 ± 7 (3–32)	150 ± 70	5 ± 4 (0.2–16)
34	24 ± 2	66 (2)	24/26/8/8	23 ± 6 (12–42)*	200 ± 60*	9 ± 5 (0.7–21)
44	61 ± 2*	57 (2)	18/30/5/4	24 ± 7 (8–45)*	210 ± 90*	10 ± 6 (0.1–25)*
61	6 ± 2*	16 (2)	10/5/1/0	24 ± 7 μm/s (14–38)*	230 ± 90*	10 ± 7 (1.3–27)
66	<1*	35 (2)	18/13/2/0	23 ± 6 (12–41)*	220 ± 70*	8 ± 5 (1.3–26)
51 heat shock	Not done	21 (1)	2/2/10/7	28 ± 6 (15–47)*	250 ± 110*	10 ± 7 (2–24)
60 heat shock	Not done	24 (1)	2/12/8/2	22 ± 6 (13–37)*	160 ± 70	8 ± 5 (1.1–18)

“Replicates” represent independent experiments done on different days with fresh cultures of B. subtilis. Tracks were characterized according to Figure 6 by visual inspection and correlation with parameters as in Figure 7. SD, standard deviation. (*), significantly different from value at 28°C (p < 0.01).