Genome‐wide screening of genes required for swarming motility in Escherichia coli K‐12

Department of Oral Microbiology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, 2-5-1, Shikata, Okayama 700-8525, Japan.
Journal of Bacteriology (Impact Factor: 2.69). 03/2007; 189(3):950-7. DOI: 10.1128/JB.01294-06
Source: PubMed

ABSTRACT Escherichia coli K-12 has the ability to migrate on semisolid media by means of swarming motility. A systematic and comprehensive collection of gene-disrupted E. coli K-12 mutants (the Keio collection) was used to identify the genes involved in the swarming motility of this bacterium. Of the 3,985 nonessential gene mutants, 294 were found to exhibit a strongly repressed-swarming phenotype. Further, 216 of the 294 mutants displayed no significant defects in swimming motility; therefore, the 216 genes were considered to be specifically associated with the swarming phenotype. The swarming-associated genes were classified into various functional categories, indicating that swarming is a specialized form of motility that requires a wide variety of cellular activities. These genes include genes for tricarboxylic acid cycle and glucose metabolism, iron acquisition, chaperones and protein-folding catalysts, signal transduction, and biosynthesis of cell surface components, such as lipopolysaccharide, the enterobacterial common antigen, and type 1 fimbriae. Lipopolysaccharide and the enterobacterial common antigen may be important surface-acting components that contribute to the reduction of surface tension, thereby facilitating the swarm migration in the E. coli K-12 strain.

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    • "After surface attachment, P. aeruginosa moves by surface motility known as twitching (Kearns et al. 2001). E. coli exhibits two flagella-driven motility types, swimming and swarming (Harshey 2003; Go´mez-Go´mez et al. 2007; Inoue et al. 2007). L. monocytogenes can also swim by means of flagella-based motility to access nutrient sources. "
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    ABSTRACT: The activity of two phenolic acids, gallic acid (GA) and ferulic acid (FA) at 1000 μg ml-1, was evaluated on the prevention and control of biofilms formed by Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Listeria monocytogenes. In addition, the effect of the two phenolic acids was tested on planktonic cell susceptibility, bacterial motility and adhesion. Biofilm prevention and control were tested using a microtiter plate assay and the effect of the phenolic acids was assessed on biofilm mass (crystal violet staining) and on the quantification of metabolic activity (alamar blue assay). The minimum bactericidal concentration for P. aeruginosa was 500 μg ml-1 (for both phenolic acids), whilst for E. coli it was 2500 μg ml-1 (FA) and 5000 μg ml-1 (GA), for L. monocytogenes it was >5000 μg ml-1 (for both phenolic acids), and for S. aureus it was 5000 μg ml-1 (FA) and >5000 μg ml-1 (GA). GA caused total inhibition of swimming (L. monocytogenes) and swarming (L. monocytogenes and E. coli) motilities. FA caused total inhibition of swimming (L. monocytogenes) and swarming (L. monocytogenes and E. coli) motilities. Colony spreading of S. aureus was completely inhibited by FA. The interference of GA and FA with bacterial adhesion was evaluated by the determination of the free energy of adhesion. Adhesion was less favorable when the bacteria were exposed to GA (P. aeruginosa, S. aureus and L. monocytogenes) and FA (P. aeruginosa and S. aureus). Both phenolics had preventive action on biofilm formation and showed a higher potential to reduce the mass of biofilms formed by the Gram-negative bacteria. GA and FA promoted reductions in biofilm activity >70% for all the biofilms tested. The two phenolic acids demonstrated the potential to inhibit bacterial motility and to prevent and control biofilms of four important human pathogenic bacteria. This study also emphasizes the potential of phytochemicals as an emergent source of biofilm control products.
    Biofouling 08/2012; 28(7):755-67. DOI:10.1080/08927014.2012.706751 · 3.70 Impact Factor
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    • "However, it should be pointed out that previous data describing the contribution of polysaccharides in swarming motility, associated it mostly with the external part of lipopolysaccharides of Gram-negative bacteria (Toguchi et al. 2000, Izquierdo et al. 2002). On the other hand, the extracellular polysaccharides are not generally considered to be crucial for swarming motility (Wang et al. 2004, Inoue et al. 2007), although their influence on this process has been described in the case of Proteus. mirabilis or Myxococcus xanthus (Gygi et al. 1995, Lu et al. 2005). "
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    ABSTRACT: Unicellular organisms naturally form multicellular communities, differentiate into specialized cells, and synchronize their behaviour under certain conditions. Swarming, defined as a movement of a large mass of bacteria on solid surfaces, is recognized as a preliminary step in the formation of biofilms. The main aim of this work was to study the role of a group of genes involved in exopolysaccharide biosynthesis during pellicle formation and swarming in Bacillus subtilis strain 168. To assess the role of particular proteins encoded by the group of epsI-epsO genes that form the eps operon, we constructed a series of insertional mutants. The results obtained showed that mutations in epsJ-epsN, but not in the last gene of the eps operon (epsO), have a severe effect on pellicle formation under all tested conditions. Moreover, the inactivation of 5 out of the 6 genes analysed caused total inhibition of swarming in strain 168 (that does not produce surfactin) on LB medium. Following restoration of the sfp gene (required for production of surfactin, which is essential for swarming of the wild-type bacteria), the sfp+ strains defective in eps genes (except epsO) generated significantly different patterns during swarming on synthetic B medium, as compared to the parental strain 168 sfp+.
    Journal of applied genetics 09/2010; 51(3):369-81. DOI:10.1007/BF03208867 · 1.90 Impact Factor
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    • "Swarming is a multicellular type of motility and is considered as a model of bacterial social behavior. Recently, it has been shown that swarming motility involves a wide variety of cellular functions (Kim & Surette, 2004; Inoue et al., 2007; Overhage et al., 2007). Thus far, swarming motility has been reported in a wide range of gramnegative bacterial species belonging to the genera Proteus, Vibrio, Aeromonas, Serratia, Salmonella, Escherichia, Yersinia, and Pseudomonas; in some of these species, swarming has been shown to be associated with virulence and resistance to antibiotics (Fraser & Hughes, 1999; Harshey, 2003; Kim et al., 2003; Merino et al., 2006). "
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    ABSTRACT: Pseudomonas aeruginosa is capable of moving by swimming, swarming, and twitching motilities. In this study, we investigated the effects of fatty acids on Pseudomonas aeruginosa PAO1 motilities. A branched-chain fatty acid (BCFA)--12-methyltetradecanoic acid (anteiso-C15:0)--has slightly repressed flagella-driven swimming motility and completely inhibited a more complex type of surface motility, i.e. swarming, at a concentration of 10 microg mL(-1). In contrast, anteiso-C15:0 exhibited no effect on pili-mediated twitching motility. Other BCFAs and unsaturated fatty acids tested in this study showed similar inhibitory effects on swarming motility, although the level of inhibition differed between these fatty acids. These fatty acids caused no significant growth inhibition in liquid cultures. Straight-chain saturated fatty acids such as palmitic acid were less effective in swarming inhibition. The wetness of the PAO1 colony was significantly reduced by the addition of anteiso-C15:0; however, the production of rhamnolipids as a surface-active agent was not affected by the fatty acid. In addition to motility repression, anteiso-C15:0 caused 31% repression of biofilm formation by PAO1, suggesting that BCFA could affect the multiple cellular activities of Pseudomonas aeruginosa.
    FEMS Microbiology Letters 05/2008; 281(1):81-6. DOI:10.1111/j.1574-6968.2008.01089.x · 2.72 Impact Factor
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