Polyphosphate in Lactobacillus and Its Link to Stress Tolerance and Probiotic Properties

Abstract

The synthesis of the inorganic polymer polyphosphate (poly-P) in bacteria has been linked to stress survival and to the capacity of some strains to sequester heavy metals. In addition, synthesis of poly-P by certain strains of probiotic lactobacilli has been evidenced as a probiotic mechanism due to the homeostatic properties of this compound at the intestinal epithelium. We analyzed the link between poly-P synthesis, stress response, and mercury toxicity/accumulation by comparing wild-type strains of Lactobacillus and their corresponding mutants devoid of poly-P synthesis capacity (defective in the poly-P kinase, ppk, gene). Results showed that resistance to salt (NaCl) and acidic (pH 4) stresses upon ppk mutation was affected in Lactobacillus casei, while no effect was observed in two different Lactobacillus plantarum strains. Inorganic [Hg(II)] and organic (CH3Hg) mercury toxicity was generally increased upon ppk mutation, but no influence was seen on the capacity to retain both mercurial forms by the bacteria. Notwithstanding, the culture supernatants of ppk-defective L. plantarum strains possessed a diminished capacity to induce HSP27 expression, a marker for cell protection, in cultured Caco-2 cells compared to wild-type strains. In summary, our results illustrate that the role of poly-P in stress tolerance can vary between strains and they reinforce the idea of probiotic-derived poly-P as a molecule that modulates host-signaling pathways. They also question the relevance of this polymer to the capacity to retain mercury of probiotics.

Complex Responses to Hydrogen Peroxide and Hypochlorous Acid by the Probiotic Bacterium Lactobacillus reuteri

“…reuteri against HOCl anaerobically, and more work will be needed to understand the mechanism underlying this effect. PolyP plays a role in stress resistance and probiotic phenotypes in several different Lactobacillus species (85–90). In E.…”

Technological characterization of vaginal probiotic lactobacilli: resistance to osmotic stress and strains compatibility

“…), an increased synthesis of inorganic polymer polyphosphate, the role of Poly‐P as a molecule that modulates host‐signalling pathways (Alcántara et al . ) or the addition of poly‐Ƴ glutamic acid (Bhat et al . ).…”

Lipoteichoic acid depletion in Lactobacillus impacts cell morphology and stress response but does not abolish mercury surface binding

“…Lactobacillus plantarum WCFS1 (Siezen et al, 2012), L. plantarum Lpp+ (Alcántara et al, 2018) and derived mutants were grown in MRS medium at 30 °C under static conditions. Escherichia coli DH10B was used as a cloning host and it was grown in LB medium at 37 °C under aeration.…”

“…However, it has not been clearly determined which cell components are involved in Hg binding. Polyphosphate, an efficient metal chelator, is produced by numerous species of lactobacilli (Alcántara et al, 2014) but has been shown to have no effect in Hg binding (Alcántara et al, 2018). Previous results suggested that Hg mainly bound the cell envelope of Lactobacillus cells (Alcántara et al, 2017).…”