Study of the biosynthesis and functionality of polyphosphate in Bifidobacterium longum KABP042

Abstract

Polyphosphate (poly-P) biosynthesis in bacteria has been linked to many physiological processes and has been characterized as an interesting functional molecule involved in intestinal homeostasis. We determined the capacity for poly-P production of 18 probiotic strains mainly belonging to Bifidobacterium and former Lactobacillus genera, showing that poly-P synthesis varied widely between strains and is dependent on the availability of phosphate and the growth phase. Bifidobacteria were especially capable of poly-P synthesis and poly-P kinase (ppk) genes were identified in their genomes together with a repertoire of genes involved in phosphate transport and metabolism. In Bifidobacterium longum KABP042, the strain we found with highest poly-P production, variations in ppk expression were linked to growth conditions and presence of phosphate in the medium. Moreover, the strain produced poly-P in presence of breast milk and lacto-N-tetraose increased the amount of poly-P synthesized. Compared to KABP042 supernatants low in poly-P, exposure of Caco-2 cells to KABP042 supernatants rich in poly-P resulted in decreased epithelial permeability and increased barrier resistance, induction of epithelial protecting factors such as HSP27 and enhanced expression of tight junction protein genes. These results highlight the role of bifidobacteria-derived poly-P as a strain-dependent functional factor acting on epithelial integrity.

Inorganic phosphate modifies stationary phase fitness and metabolic pathways in Lactiplantibacillus paraplantarum CRL 1905

“…Variations in environmental Pi could constitute a simple strategy triggering phenotypical adaptations to improve survival and tolerance to harsh conditions that lactobacilli must thrive. Studies in Pi surplus condition to elucidate regulatory pathways concerning the presented differential phenotypes in L. paraplantarum become of relevance, since there are scarce reports in LAB regarding to the Pi metabolism and the physiological responses to Pi ( Alvarez-Martin et al, 2012 ; Monedero et al, 2017 ; Alcántara et al, 2023 ), focused in Pi deficiency. Further studies should be performed to elucidate the molecular regulatory processes that modify the protein profile and generate the pleiotropic responses presented herein.…”