Roles for flagellar stators in biofilm formation by Pseudomonas aeruginosa.

While Pseudomonas aeruginosa has only a single flagellum, its genome encodes two flagellar stators, called MotAB and MotCD. Here we report that despite no apparent alterations in swimming motility, mutations in either the MotAB or the MotCD stator render the strains defective for biofilm formation in both static and flow cell systems. Our data suggest distinct roles for the stators in early biofilm formation, with both the MotAB and MotCD stators playing a role in initial polar attachment of the bacterial cell to the surface (reversible attachment) and the MotAB stator also participating in the downstream adherence event of irreversible attachment.

Saccharomyces cerevisiae-based molecular tool kit for manipulation of genes from gram-negative bacteria.

A tool kit of vectors was designed to manipulate and express genes from a wide range of gram-negative species by using in vivo recombination. Saccharomyces cerevisiae can use its native recombination proteins to combine several amplicons in a single transformation step with high efficiency. We show that this technology is particularly useful for vector design.

An increased level of alternative sigma factor RpoS partially suppresses drug hypersensitivity associated with inactivation of the multidrug resistance pump AcrAB in Escherichia coli.

Constitutive expression of stationary phase alternative sigma factor RpoS in Escherichia coli during the exponential phase was found to partially suppress drug sensitivity associated with an acrAB mutation that inactivates the major multidrug resistance pump, suggesting that Rpos might significantly contribute to multidrug resistance, underscoring yet another role for this important stress-related transcription factor.

Evidence for two flagellar stators and their role in the motility of Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a ubiquitous bacterium capable of twitching, swimming, and swarming motility. In this study, we present evidence that P. aeruginosa has two flagellar stators, conserved in all pseudomonads as well as some other gram-negative bacteria.

Role of CysE in production of an extracellular signaling molecule in Providencia stuartii and Escherichia coli: loss of CysE enhances biofilm formation in Escherichia coli.

A mini-Tn5Cm insertion has been identified that significantly reduced the amount of an extracellular activating signal for a lacZ fusion (cma37::lacZ) in Providencia stuartii. The transposon insertion was located immediately upstream of an open reading frame encoding a putative CysE ortholog. The CysE enzyme, serine acetyltransferase, catalyzes the conversion of serine to O-acetyl-L-serine (OAS).