Interestingly, G9241 did not display motility when grown planktonically in CO2/bicarbonate, but rather appeared to be upregulating capsule production in this putatively host-like environment.
Motility of both of these strains was highly impaired in the presence of 500 μg/ml polymyxin B. Swarming motility results in the absence of polymyxin B for RSF44 are similar to those reported for a Pseudomonas aeruginosa mutant lacking both flagella and the type IV pili, which began to undergo sliding motility when grown under conditions required for swarming motility [ 33].
Although L. monocytogenes has been reported to show flagellar motility only when grown at ≤ 30°C [ 50, 51], our results are consistent with the observation that strain 10403S, which was used in this study, has been shown to express flagellin at 37°C [ 51].
B. cereus strains exhibit a range of motility behavior [3], and both G9241 and 10987 displayed observable motility by microscopy when grown in rich broth.
AltDE and AltDE1 genomes differed with regard to their flagellar operons and that AltDE1 displayed significantly higher motility than AltDE when grown in RM at 25°C [ 3].
When grown on soft surfaces, the collective motility is reflected by the formation of foraging swarms [ 14] that act as arms sent out in search for food (Additional file 1 section I and Additional files 2, 3, 4, 5, 6).
However, SdiA is slightly active when grown in liquid broth, and is highly active when grown in motility agar [2].
Our observations showed that the transcriptomes of Hvo and NRC-1 regulated stress, motility, and ABC transporters in a similar manner, which is in line with previous reports from other prokaryotes when grown in an acidic environment.
When grown in NBG medium containing 0.5-1.0 0.5-1.0agar, S. typhimurium undergoes swarmer differentiation and exhibits surface motility (Fig. 1).
Loss of csA did not affect development in the mutant cells under laboratory conditions, however when grown on soil plates which resembles natural conditions the mutant cells displayed reduced cell-cell adhesion, increased adhesiveness to the substratum, and slower motility, which led to their sorting out from aggregating wild-type cells [26] [26].
They may weight 1-3 pounds when grown.
