TABLE 2.

Swarming rates of S. meliloti RMB7201 and Tn5 FS mutants in various media

Medium	Swarming rate (avg change in colony radius [mm/h] ± SD)a
	RMB7201	FS1	FS7	FS44
TY (1/20), 0.3% agar	0.50 ± 0.019	1.0 ± 0.018	1.0 ± 0.018	1.0 ± 0.012
Soil extract,b 0.3% agar	0.35 ± 0.022	0.50 ± 0.00	0.50 ± 0.00	NDc
CB, 0.3% agar	0.29 ± 0.00	0.40 ± 0.036	0.40 ± 0.031	0.37 ± 0.036
TY (1/20), moist sand	0.64 ± 0.039	1.2 ± 0.076	1.1 ± 0.073	0.92 ± 0.14
TY (1/20) in 0.2% CMC	3.0 ± 0.43	4.6 ± 0.46	4.6 ± 0.29	3.6 ± 0.31

^aValues are averages taken from replicate plates in a representative experiment after 40 h, except for CMC-amended 1/20 TY, liquid medium, where rates were determined 6 to 9.5 h after inoculation. 

^bSoil extract solution was obtained by adding 1 liter of tap water to 500 g of soil (Crosby silt loam), mixing it, and centrifuging it at 5,800 × g and 35,000 × g for 15 min each to remove particles. The soil solution was then concentrated ninefold in a rotary evaporator and filter sterilized through 0.2-μm-pore-size membranes. 

^cND, not determined.