An Inducible Operon Is Involved in Inulin Utilization in Lactobacillus plantarum Strains, as Revealed by Comparative Proteogenomics and Metabolic Profiling

Abstract

Inulin is a long-chain carbohydrate that may act as a prebiotic, which provides many health benefits to the host by selectively stimulating the growth and activity of beneficial bacteria in the colon. While certain lactobacilli can catabolize inulin, this has not yet been described for Lactobacillus plantarum, and an associated putative inulin operon has not been reported in this species. By using comparative and functional genomics, we showed that two L. plantarum strains utilized inulin and identified functional inulin operons in their genomes. The proteogenomic data revealed that inulin degradation and uptake routes, which related to the fosRABCDXE operon and pstBCA genes, were widely expressed among L. plantarum strains. The present work provides a novel understanding of gene regulation and mechanisms of inulin utilization in probiotic L. plantarum generating opportunities for synbiotic product development.

Development of omics‐based protocols for the microbiological characterization of multi‐strain formulations marketed as probiotics: the case of VSL#3

“…Urease-encoding sequences were only identified in S. thermophilus, thus confirming that this enzymatic activity is uniquely present in this species among those constituting the VSL#3 product. A putative L. paracasei levanase coding sequence was also identified, thus suggesting the potential ability of VSL#3 L. paracasei BP07 to hydrolyse inulin, as recently demonstrated in for an L. plantarum strain carrying this conserved gene (Buntin et al, 2017).…”

“…Subsequently, aliquots containing 40 µg of protein were prepared in triplicate for denaturing polyacrylamide gel electrophoresis on a pre‐cast Invitrogen Bolt 4–12% Bis‐Tris Plus gel after heating for 5 min at 95°C. Protein separation, excision of gel slices (four per loaded sample), reduction and alkylation, tryptic digestion and analysis by nLC (Proxeon EASY) connected to a LTQ‐Orbitrap XL (Thermo Electron) were performed as described previously (Oosterkamp et al , ; Buntin et al , ). Spectra were analysed using MaxQuant 1.5.2.8 and a database of common contaminants, next to protein databases of the reported genomes of the VSL#3 strains, which were used as input (Douillard et al , , 16.468 sequences) and those of Escherichia coli K12 and BL21‐DE3 as possible contaminants.…”

The local transcriptional regulators SacR1 and SacR2 act as repressors of fructooligosaccharides metabolism in Lactobacillus plantarum

“…When combining the predicted TFBSs of SacR1 and SacR2 with our present results, we deduced a consensus sequence for the SacR1 and SacR2 binding sites, WNNNNNAACGNNTTNNNNNW, which is also similar to the consensus sequence of cre sites [19,26]. Many studies revealed a double effect of global and local regulation on carbohydrate metabolism in LAB [39,40]. In contrast to these global regulators, local regulators regulate only one or a few genes that are often linked genetically to the gene encoding the regulator itself [41].…”

Metabolic diversity of bacteria and yeast from commercial probiotic products illustrated by phenotypic profiling

“…Lactobacillus plantarum strains showed a very consistent pattern 444 of sugar utilization, with 14 sugar wells having a positive reaction for all five of the strains tested. These 445 results correlate with comparative functional genomics and metabolic profiling studies on L. plantarum 446 [30] [45]. L. plantarum probiotic strains, but not L. rhamnosus, utilized the complex polysaccharide, 447 pectin (Well F1), found in the skins of many fruits.…”