Swarming motility in Bacillus cereus and characterization of a fliY mutant impaired in swarm cell differentiation The EMBL accession number for the sequence reported in this paper is Y08031.

Abstract

This report describes a new behavioural response of Bacillus cereus that consists of a surface-induced differentiation of elongated and hyperflagellated swarm cells exhibiting the ability to move collectively across the surface of the medium. The discovery of swarming motility in B. cereus paralleled the isolation of a spontaneous non-swarming mutant that was found to carry a deletion of fliY, the homologue of which, in Bacillus subtilis, encodes an essential component of the flagellar motor-switch complex. However, in contrast to B. subtilis, the fliY mutant of B. cereus was flagellated and motile, thus suggesting a different role for FliY in this organism. The B. cereus mutant was completely deficient in chemotaxis and in the secretion of the L 2 component of the tripartite pore-forming necrotizing toxin, haemolysin BL, which was produced exclusively by the wild-type strain during swarm-cell differentiation. All the defects in the fliY mutant of B. cereus could be complemented by a plasmid harbouring the B. cereus fliY gene. These results demonstrate that the activity of fliY is required for swarming and chemotaxis in B. cereus, and suggest that swarm-cell differentiation is coupled with virulence in this organism.

FlhF, a signal recognition particle-like GTPase, is involved in the regulation of flagellar arrangement, motility behaviour and protein secretion in Bacillus cereus

“…6). This finding is in agreement with a robust literature demonstrating that deletions in flagellar genes severely impair or abolish the ability to undergo swarming differentiation in swarming-proficient species (Gygi et al, 1995;Harshey & Matsuyama, 1994;O'Rear et al, 1992;Senesi et al, 2002;Young et al, 1999b). In addition, flhF has been recently demonstrated to be required for swarming motility in the Gram-negative species P. aeruginosa (Murray & Kazmierczak, 2006).…”

“…For several flagellated bacteria, surface sensing is an environmental signal inducing swarming differentiation, a specialized form of flagellum-driven motility that is exhibited by a wide range of species when transferred from liquid to solid growth media (Allison & Hughes, 1991;Ghelardi et al, 2002;Kearns & Losick, 2003;McCarter, 1999;Senesi et al, 2002). This surface-induced motility is dependent on the production of differentiated swarm cells that are aseptate, multinucleate and elongated, and express a higher number of peritrichously placed flagella than the corresponding oligoflagellated swimmer cells (for a review see Fraser & Hughes, 1999).…”

Inorganic polyphosphate in Bacillus cereus : Motility, biofilm formation, and sporulation

“…B. cereus has alternative forms of flagella-driven motility, such as swimming by individual cells with short and few flagella and swarming by collective swarm cells with long and many flagellae (23). Each of the mutants (ppk, ppx, and pap) showed impairment in both types (Fig.…”

Quorum signal molecules as biosurfactants affecting swarming in Rhizobium etli

“…This process and other forms of surface motility (reviewed in ref. 9) are found in many bacterial genera (11)(12)(13)(14)(15). Swarmer cells are often hyperflagellated, elongated, and multinucleated.…”