Poly-γ-glutamic acid (γ-PGA) is an important natural biopolymer that is used widely in fields of foods, medicine, cosmetics, and agriculture. Several B. amyloliquefaciens LL3 mutants were constructed to improve γ-PGA synthesis via single or multiple marker-less in-frame deletions of four gene clusters (itu, bae, srf, and fen) encoding antibiotic substances. γ-PGA synthesis by the Δsrf mutant sh...

Low-temperature ecosystems represent the largest biosphere on Earth, and yet our understanding of the roles of bacteriophages in these systems is limited. Here, the influence of the cold-active filamentous phage SW1 on the phenotype and gene transcription of its host, Shewanella piezotolerans WP3 (WP3), was investigated by construction of a phage-free strain (WP3ΔSW1), which was compared with t...

AlgR is a key Pseudomonas aeruginosa transcriptional response regulator required for virulence. AlgR activates alginate production and twitching motility but represses the Rhl quorum-sensing (QS) system, including rhamnolipid production. The role of AlgR phosphorylation is enigmatic, since phosphorylated AlgR (AlgR-P) is required for twitching motility through the fimU promoter but is not requi...

Swarming is a mode of translocation dependent on flagellar activity that allows bacteria to move rapidly across surfaces. In several bacteria, swarming is a phenotype regulated by quorum sensing. It has been reported that the swarming ability of the soil bacterium Sinorhizobium meliloti Rm2011 requires a functional ExpR/Sin quorum-sensing system. However, our previous published results demonstr...

Bacterial swarming is a type of motility characterized by a rapid and collective migration of bacteria on surfaces. Most swarming species form densely packed dynamic clusters in the form of whirls and jets, in which hundreds of rod-shaped rigid cells move in circular and straight patterns, respectively. Recent studies have suggested that short-range steric interactions may dominate hydrodynamic...

Bacteria can coordinate several multicellular behaviors in response to environmental changes. Among these, swarming and biofilm formation have attracted significant attention for their correlation with bacterial pathogenicity. However, little is known about when and where the signaling occurs to trigger either swarming or biofilm formation. We have previously identified an RssAB two-component s...

Swarming motility of Serratia liquefaciens MG1 requires the expression of two genetic loci, flhDC and swrI. Here we demonstrate that the products of the flhDC operon (the flagellar master regulator) and the swrI gene (the extracellular signal molecule N-butanoyl-L-homoserine lactone) are global regulators which control two separate regulons.