Revised Aspects into the Molecular Bases of Hydroxycinnamic Acid Metabolism in Lactobacilli.

Hydroxycinnamic acids (HCAs) are phenolic compounds produced by the secondary metabolism of edible plants and are the most abundant phenolic acids in our diet. The antimicrobial capacity of HCAs is an important function attributed to these phenolic acids in the defense of plants against microbiological threats, and bacteria have developed diverse mechanisms to counter the antimicrobial stress imposed by these compounds, including their metabolism into different microbial derivatives. The metabolism of HCAs has been intensively studied in spp.

Non-redundant functionality of Lactiplantibacillus plantarum phospho-β-glucosidases revealed by carbohydrate utilization signatures associated to pbg2 and pbg4 gene mutants.

Aim: To increase our knowledge on the functionality of 6-phospho-β-glucosidases linked to phosphoenolpyruvate-dependent phosphotransferase systems (PTS) that are encountered in high redundancy in the Lactiplantibacillus plantarum WCFS1 genome.

Methods And Results: Two L. plantarum WCFS1 gene mutants that lacked one of the 6-phospho-β-glucosidases, ∆pbg2 (or ∆lp_0906) or ∆pbg4 (or ∆lp_2777) were constructed and the metabolic impact of these mutations assessed by high-throughput phenotyping (Omnilog).

Molecular Responses of Lactobacilli to Plant Phenolic Compounds: A Comparative Review of the Mechanisms Involved.

Lactobacilli are well-studied bacteria that can undergo oxidative selective pressures by plant phenolic compounds (PPCs) in plants, during some food fermentations or in the gastrointestinal tract of animals via dietary inputs. Lactobacilli are known to be more tolerant to PPCs than other bacterial groups and, therefore, must have mechanisms to cope with the effects of these metabolites. In this review, we intend to present what is currently known about the basics beyond the responses of spp.

Transcriptomic Evidence of Molecular Mechanisms Underlying the Response of Lactobacillus Plantarum WCFS1 to Hydroxytyrosol.

: This study was aimed to gain new insights into the molecular mechanisms used by WCFS1 to respond to hydroxytyrosol (HXT), one of the main and health-relevant plant phenolics present in olive oil. To this goal, whole genome transcriptomic profiling was used to better understand the contribution of differential gene expression in the adaptation to HXT by this microorganism. The transcriptomic profile reveals an HXT-triggered antioxidant response involving genes from the ROS (reactive oxygen species) resistome of , genes coding for HS-producing enzymes and genes involved in the response to thiol-specific oxidative stress.

Oleuropein Transcriptionally Primes to Interact With Plant Hosts.

Oleuropein (OLE) is a secoiridoid unique to known to play a role in the plant-herbivore interaction. However, it is not clear how this molecule is induced to mediate plant responses to microbes and how microbes, in turn, withstand with OLE. To better understand how OLE affects the plant-microbe interaction, the contribution of differential gene expression in the adaptation to OLE was characterized by whole genome transcriptional profiling in , a bacterium associated to the olive.

Ethylphenol Formation by Lactobacillus plantarum: Identification of the Enzyme Involved in the Reduction of Vinylphenols.

Ethylphenols are strong odorants produced by microbial activity that are described as off flavors in several foods. is a lactic acid bacterial species able to produce ethylphenols by the reduction of vinylphenols during the metabolism of hydroxycinnamic acids. However, the reductase involved has not been yet uncovered.

Unravelling the Reduction Pathway as an Alternative Metabolic Route to Hydroxycinnamate Decarboxylation in Lactobacillus plantarum.

is the lactic acid bacterial species most frequently found in plant-food fermentations where hydroxycinnamic acids are abundant. efficiently decarboxylates these compounds and also reduces them, yielding substituted phenylpropionic acids. Although the reduction step is known to be induced by a hydroxycinnamic acid, the enzymatic machinery responsible for this reduction pathway has not been yet identified and characterized.

Transcriptome-Based Analysis in Lactobacillus plantarum WCFS1 Reveals New Insights into Resveratrol Effects at System Level.

Scope: This study was undertaken to expand our insights into the mechanisms involved in the tolerance to resveratrol (RSV) that operate at system-level in gut microorganisms and advance knowledge on new RSV-responsive gene circuits.

Methods And Results: Whole genome transcriptional profiling was used to characterize the molecular response of Lactobacillus plantarum WCFS1 to RSV. DNA repair mechanisms were induced by RSV and responses were triggered to decrease the load of copper, a metal required for RSV-mediated DNA cleavage, and H S, a genotoxic gas.

Transcriptional Reprogramming at Genome-Scale of WCFS1 in Response to Olive Oil Challenge.

Dietary fats may exert selective pressures on species, however, knowledge on the mechanisms of adaptation to fat stress in these organisms is still fragmentary. This study was undertaken to gain insight into the mechanisms of adaptation of WCFS1 to olive oil challenge by whole genome transcriptional profiling using DNA microarrays. A set of 230 genes were differentially expressed by WCFS1 to respond to this vegetable oil.

Differential Gene Expression by Lactobacillus plantarum WCFS1 in Response to Phenolic Compounds Reveals New Genes Involved in Tannin Degradation.

is a lactic acid bacterium that can degrade food tannins by the successive action of tannase and gallate decarboxylase enzymes. In the genome, the gene encoding the catalytic subunit of gallate decarboxylase (, or ) is only 6.5 kb distant from the gene encoding inducible tannase ( [ ], or ).

Molecular adaptation of Lactobacillus plantarum WCFS1 to gallic acid revealed by genome-scale transcriptomic signature and physiological analysis.

Background: Gallic acid (GA) is a model hydroxybenzoic acid that occurs esterified in the lignocellulosic biomass of higher plants. GA displays relevant biological activities including anticancer properties. Owing to its antimicrobial and cellulase-inhibiting activities, GA also imposes constraints to the fermentability of lignocellulosic hydrolysates.

Bioactive compounds produced by gut microbial tannase: implications for colorectal cancer development.

The microorganisms in the human gastrointestinal tract have a profound influence on the transformation of food into metabolites which can impact human health. Gallic acid (GA) and pyrogallol (PG) are bioactive compounds displaying diverse biological properties, including carcinogenic inhibiting activities. However, its concentration in fruits and vegetables is generally low.

Genetic and biochemical approaches towards unravelling the degradation of gallotannins by Streptococcus gallolyticus.

Background: Herbivores have developed mechanisms to overcome adverse effects of dietary tannins through the presence of tannin-resistant bacteria. Tannin degradation is an unusual characteristic among bacteria. Streptococcus gallolyticus is a common tannin-degrader inhabitant of the gut of herbivores where plant tannins are abundant.

Characterization of a bacterial tannase from Streptococcus gallolyticus UCN34 suitable for tannin biodegradation.

The gene in the locus GALLO_1609 from Streptococcus gallolyticus UCN34 was cloned and expressed as an active protein in Escherichia coli BL21 (DE3). The protein was named TanSg1 since it shows similarity to bacterial tannases previously described. The recombinant strain produced His-tagged TanSg1 which was purified by affinity chromatography.

Tannic acid-dependent modulation of selected Lactobacillus plantarum traits linked to gastrointestinal survival.

Background: Owing to its antimicrobial properties dietary tannins may alter the functional efficacy of probiotic lactobacilli in the gastrointestinal (GI)-tract influencing their growth, viability and molecular adaptation to the intestinal environment.

Methods And Findings: The effects of tannic acid on Lactobacillus plantarum WCFS1 were studied by in vitro growth monitoring and visualizing the morphological alteration on the cell wall using transmission electron microscopy. Growth upon tannic acid was characterized by dose-dependent reductions of initial viable counts and extended lag phases.

Genome-wide transcriptomic responses of a human isolate of Lactobacillus plantarum exposed to p-coumaric acid stress.

Scope: To advance knowledge of the stress tolerance mechanisms of a probiotic Lactobacillus plantarum strain to dietary hydroxycinnamic acids and the role of gut commensal microorganisms in the bioactivation of polyphenols.

Methods And Results: To understand how gut commensal microorganisms tolerate toxicity of hydroxycinnamic acids and bioactivate these compounds, we used whole genome transcriptional profiling to characterize the response of a L. plantarum human isolate during challenge with p-coumaric acid (p-CA).

Response of a Lactobacillus plantarum human isolate to tannic acid challenge assessed by proteomic analyses.

Scope: To gain insight on the mechanisms used by intestinal bacteria to adapt and resist the antimicrobial action of dietary tannins and identify targets for tannic acid in Lactobacillus plantarum.

Methods And Results: A proteomic analysis of an L. plantarum human isolate exposed to the tannic acid challenge was undertaken.

Delaying effect of a wine Lactobacillus plantarum strain on the coloration and xanthylium pigment formation occurring in (+)-catechin and (-)-epicatechin wine model solutions.

This article reports for the first time on the capacity of a wine Lactobacillus plantarum strain to alter the oxidative coloration of (+)-catechin and (-)-epicatechin hydroethanolic wine model solutions in the presence of Fe(2+) as catalyst. The time course of color development and pigment formation in the solutions was tracked over 42 days. The pigments formed were characterized as xanthylium structures regardless of the flavanol isomer present in the solution.

Food phenolics and lactic acid bacteria.

Phenolic compounds are important constituents of food products of plant origin. These compounds are directly related to sensory characteristics of foods such as flavour, astringency, and colour. In addition, the presence of phenolic compounds on the diet is beneficial to health due to their chemopreventive activities against carcinogenesis and mutagenesis, mainly due to their antioxidant activities.

Multiple control of the acetate pathway in Lactococcus lactis under aeration by catabolite repression and metabolites.

To explore the factors controlling metabolite formation under aeration in Lactococcus lactis, metabolic patterns, enzymatic activities, and transcriptional profiles of genes involved in the aerobic pathway for acetate anabolism were compared between a parental L. lactis strain and its NADH-oxidase-overproducer derivative. Deregulated catabolite repression mutans in the ccpA or pstH genes, encoding CcpA or its co-activator HPr, respectively, were compared with a parental strain, as well.