English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Pediococcus parvulus  2.6 secretes a 2-substituted (1,3)-β- D -glucan with prebiotic and immunomodulatory properties. It is synthesized by the GTF glycosyltransferase using UDP-glucose as substrate. Analysis of the  P. parvulus  2.6 draft genome revealed the existence of a sorbitol utilization cluster of six genes ( gutFRMCBA ), whose products should be involved in sorbitol utilization and could generate substrates for UDP-glucose synthesis. Southern blot hybridization analysis showed that the cluster is located in a plasmid. Analysis of metabolic fluxes and production of the exopolysaccharide revealed that: (i)  P. parvulus  2.6 is able to metabolize sorbitol, (ii) sorbitol utilization is repressed in the presence of glucose and (iii) sorbitol supports the synthesis of 2-substituted (1,3)-β- D -glucan. The sorbitol cluster encodes two putative regulators, GutR and GutM, in addition to a phosphoenolpyruvate-dependent phosphotransferase transport system and sorbitol-6-phosphate dehydrogenase. Therefore, we investigated the involvement of GutR and GutM in the expression of  gutFRMCBA . The promoter-probe vector pRCR based on the  mrfp  gene, which encodes the fluorescence protein mCherry, was used to test the potential promoter of the cluster (P  gut  ) and the genes encoding the regulators. This was performed by transferring by electrotransformation the recombinant plasmids into two hosts, which metabolize sorbitol:  Lactobacillus plantarum  and  Lactobacillus casei . Upon growth in the presence of sorbitol, but not of glucose, only the presence of P  gut   was required to support expression of  mrfp  in  L. plantarum . In  L. casei  the presence of sorbitol in the growth medium and the pediococcal  gutR  or  gutR  plus  gutM  in the genome was required  for  P  gut   functionality. This demonstrates that: (i) P  gut   is required for expression of the  gut  cluster, (ii) P  gut   is subjected to catabolic repression in lactobacilli, (iii) GutR is an activator, and (iv) in the presence of sorbitol,  trans -complementation for activation of P  gut   exists in  L. plantarum  but not in  L. casei .

frontiers in microbiology

Characterization of the Sorbitol Utilization Cluster of the Probiotic Pediococcus parvulus 2.6: Genetic, Functional and Complementation Studies in Heterologous Hosts