Effect of Spermidine on Biofilm Formation in Escherichia coli K-12

Abstract

Polyamines are essential for biofilm formation in Escherichia coli, but it is still unclear which polyamines are primarily responsible for this phenomenon. To address this issue, we constructed a series of E. coli K-12 strains with mutations in genes required for the synthesis and metabolism of polyamines. Disruption of the spermidine synthase gene (speE) caused a severe defect in biofilm formation. This defect was rescued by the addition of spermidine to the medium, but not by putrescine or cadaverine. A multidrug/spermidine efflux pump membrane subunit (MdtJ)-deficient strain was anticipated to accumulate more spermidine and result in enhanced biofilm formation than the MdtJ+ strain. However, the mdtJ mutation did not affect intracellular spermidine or biofilm concentrations. E. coli has the spermidine acetyltransferase (SpeG) and glutathionylspermidine synthetase/amidase (Gss) to metabolize intracellular spermidine. Under the biofilm-forming condition, not Gss but SpeG plays a major role in decreasing the too high intracellular spermidine concentrations. Additionally, PotFGHI can function as a compensatory importer of spermidine when PotABCD is absent under the biofilm-forming condition. Lastly, we reported here that, in addition to intracellular spermidine, the periplasmic binding protein (PotD) of the spermidine preferential ABC transporter is essential for stimulating biofilm formation. IMPORTANCE Previous reports have speculated on the effect of polyamines on bacterial biofilm formation. However, the regulation of biofilm formation by polyamines in Escherichia coli has not yet been assessed. The identification of polyamines that stimulate biofilm formation is important for developing novel therapies for biofilm-forming pathogens. This study sheds light on biofilm regulation in E. coli. Our findings provide conclusive evidence that only spermidine can stimulate biofilm formation in E. coli cells, but not putrescine and cadaverine. Lastly, ΔpotD inhibits biofilm formation even though the spermidine is synthesized inside the cells from putrescine. Since PotD is significant for biofilm formation and there is no ortholog of PotABCD transporter in humans, PotD could be a target for the development of biofilm inhibitors.

ABC Transporters are Hub Genes in Response of Resistant E. Coli ST131 to Ciprofloxacin

“…of lptF results in a filamenting phenotype increased sensitivity to hydrophobic antibiotics and an altered form of lipopolysaccharides [28]. The potABCD operon encodes a polyamine (putrescine/spermidine) transport system [29]. In both eukaryotes and prokaryotes, normal growth and multiplication are completely dependent on polyamines [30].…”

Spore-Forming Lactic Acid-Producing Bacterium Bacillus coagulans Synthesizes and Excretes Spermidine into the Extracellular Space

“…The instrument was used as previously described. 28 Values are the averages of three independent cultures ± standard deviations.…”

“…After passing through the Millex-LH filter, the filtrates were subjected to HPLC analysis as described previously. 28,29 Isolation of the Intermediate from the Cells of Strain YF48. For preculture, 10 mL of LB medium containing 100 μg/mL of ampicillin in 100 mL Erlenmeyer flasks was inoculated with a single colony of strain YF48.…”

Improvement of putrescine production through the arginine decarboxylase pathway in Escherichia coli K-12

“…The chromosomal genes speD, and argR were replaced with FRT (FLP recombination target)- kan R -FRT from the Keio gene knockout collection (Baba et al 2006 ) by P1 vir transduction (Miller 1972 ). The disruption of speG , potE, and the ATP binding site of the puuA gene were described previously (Kurihara et al 2008 , 2009b ; Thongbhubate et al 2021 ). The patA and potFGHI genes were disrupted by a method described previously (Datsenko and Wanner 2000 ) using pKD13 as a template for the PCR amplification with delta-ygjG F and delta-ygjG R as primers for patA , and potF-up and potI-down as primers for potFGHI (Additional file 1 : Table S1).…”

“…Two spermidine transporters, PotABCD and MdtJI, and six putrescine transporters, PuuP, YdcSTUV, PlaP, PotE, PotFGHI, and SapBCDF, have been identified (Kashiwagi et al 1992 ; Pistocchi et al 1993 ; Kurihara et al 2009a , b ; Kurihara et al 2011 ; Saier et al 2016 ; Sugiyama et al 2016 ). We recently reported that PotFGHI can import spermidine under biofilm-forming conditions (Thongbhubate et al 2021 ).

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