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

2018 ◽  
Vol 84 (15) ◽  
Author(s):  
Laura Santamaría ◽  
Inés Reverón ◽  
Félix López de Felipe ◽  
Blanca de las Rivas ◽  
Rosario Muñoz
Keyword(s):  
Lactic Acid ◽  
Lactobacillus Plantarum ◽  
Metabolic Response ◽  
Reductase Activity ◽  
Bacterial Species ◽  
Hydroxycinnamic Acids ◽  
Hydroxyl Group ◽  
Transcriptomic Response ◽  
Content Type

ABSTRACT Lactobacillus plantarum is the lactic acid bacterial species most frequently found in plant-food fermentations where hydroxycinnamic acids are abundant. L. plantarum 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. A previous study on the transcriptomic response of L. plantarum to p-coumaric acid revealed a marked induction of two contiguous genes, lp_1424 and lp_1425, encoding putative reductases. In this work, the disruption of these genes abolished the hydroxycinnamate reductase activity of L. plantarum, supporting their involvement in such chemical activity. Functional in vitro studies revealed that Lp_1425 (HcrB) exhibits hydroxycinnamate reductase activity but was unstable in solution. In contrast, Lp_1424 (HcrA) was inactive but showed high stability. When the hcrAB genes were co-overexpressed, the formation of an active heterodimer (HcrAB) was observed. Since L. plantarum reductase activity was only observed on hydroxycinnamic acids (o-coumaric, m-coumaric, p-coumaric, caffeic, ferulic, and sinapic acids), the presence of a hydroxyl group substituent on the benzene ring appears to be required for activity. In addition, hydroxycinnamate reductase activity was not widely present among lactic acid bacteria, and it was associated with the presence of hcrAB genes. This study revealed that L. plantarum hydroxycinnamate reductase is a heterodimeric NADH-dependent coumarate reductase acting on a carbon-carbon double bond. IMPORTANCE Lactobacillus plantarum is a bacterial species frequently found in the fermentation of vegetables where hydroxycinnamic acids are present. The bacterial metabolism on these compounds during fermentation plays a fundamental role in the biological activity of hydroxycinnamates. L. plantarum strains exhibit an as yet unknown reducing activity, transforming hydroxycinnamates to substituted phenylpropionic acids, which possess higher antioxidant activity than their precursors. The protein machinery involved in hydroxycinnamate reduction, HcrAB, was genetically identified and characterized. The heterodimeric NADH-dependent coumarate reductase HcrAB described in this work provides new insights on the L. plantarum metabolic response to counteract the stressful conditions generated by food phenolics.

scholarly journals Enantioselective Regulation of Lactate Racemization by LarR in Lactobacillus plantarum

2014 ◽  
Vol 197 (1) ◽  
pp. 219-230 ◽  
Author(s):  
Benoît Desguin ◽  
Philippe Goffin ◽  
Nordine Bakouche ◽  
Aurélie Diman ◽  
Eric Viaene ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactobacillus Plantarum ◽  
Point Mutations ◽  
Racemic Mixture ◽  
Content Type ◽  
Sugar Fermentation ◽  
Gel Retardation ◽  
Positive Effect

Lactobacillus plantarumis a lactic acid bacterium that produces a racemic mixture ofl- andd-lactate from sugar fermentation. The interconversion of lactate isomers is performed by a lactate racemase (Lar) that is transcriptionally controlled by thel-/d-lactate ratio and maximally induced in the presence ofl-lactate. We previously reported that the Lar activity depends on the expression of two divergently oriented operons: (i) thelarABCDEoperon encodes the nickel-dependent lactate racemase (LarA), its maturases (LarBCE), and a lactic acid channel (LarD), and (ii) thelarR(MN)QOoperon encodes a transcriptional regulator (LarR) and a four-component ABC-type nickel transporter [Lar(MN), in which the M and N components are fused, LarQ, and LarO]. LarR is a novel regulator of the Crp-Fnr family (PrfA group). Here, the role of LarR was further characterizedin vivoandin vitro. We show that LarR is a positive regulator that is absolutely required for the expression of Lar activity. Using gel retardation experiments, we demonstrate that LarR binds to a 16-bp palindromic sequence (Lar box motif) that is present in thelarR-larAintergenic region. Mutations in the Lar box strongly affect LarR binding and completely abolish transcription from thelarApromoter (PlarA). Two half-Lar boxes located between the Lar box and the −35 box of PlarApromote LarR multimerization on DNA, and point mutations within one or both half-Lar boxes inhibit PlarAinduction byl-lactate. Gel retardation and footprinting experiments indicate thatl-lactate has a positive effect on the binding and multimerization of LarR, whiled-lactate antagonizes the positive effect ofl-lactate. A possible mechanism of LarR regulation by lactate enantiomers is proposed.

scholarly journals Interactions between Cooccurring Lactic Acid Bacteria in Honey Bee Hives

2015 ◽  
Vol 81 (20) ◽  
pp. 7261-7270 ◽  
Author(s):  
Z. P. Rokop ◽  
M. A. Horton ◽  
I. L. G. Newton
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Honey Bee ◽  
Bacterial Species ◽  
Antibiotic Sensitivity ◽  
Community Members ◽  
Carbohydrate Utilization ◽  
Content Type ◽  
Operational Taxonomic Units

ABSTRACTIn contrast to the honey bee gut, which is colonized by a few characteristic bacterial clades, the hive of the honey bee is home to a diverse array of microbes, including many lactic acid bacteria (LAB). In this study, we used culture, combined with sequencing, to sample the LAB communities found across hive environments. Specifically, we sought to use network analysis to identify microbial hubs sharing nearly identical operational taxonomic units, evidence which may indicate cooccurrence of bacteria between environments. In the process, we identified interactions between noncore bacterial members (FructobacillusandLactobacillaceae) and honey bee-specific “core” members. BothFructobacillusandLactobacillaceaecolonize brood cells, bee bread, and nectar and may serve the role of pioneering species, establishing an environment conducive to the inoculation by honey bee core bacteria. Coculture assays showed that these noncore bacterial members promote the growth of honey bee-specific bacterial species. Specifically,Fructobacillusby-products in spent medium supported the growth of the Firm-5 honey bee-specific cladein vitro. Metabolic characterization ofFructobacillususing carbohydrate utilization assays revealed that this strain is capable of utilizing the simple sugars fructose and glucose, as well as the complex plant carbohydrate lignin. We testedFructobacillusfor antibiotic sensitivity and found that this bacterium, which may be important for establishment of the microbiome, is sensitive to the commonly used antibiotic tetracycline. Our results point to the possible significance of “noncore” and environmental microbial community members in the modulation of honey bee microbiome dynamics and suggest that tetracycline use by beekeepers should be limited.

scholarly journals Enhancing Terpene Yield from Sugars via Novel Routes to 1-Deoxy-d-Xylulose 5-Phosphate

2014 ◽  
Vol 81 (1) ◽  
pp. 130-138 ◽  
Author(s):  
James Kirby ◽  
Minobu Nishimoto ◽  
Ruthie W. N. Chow ◽  
Edward E. K. Baidoo ◽  
George Wang ◽  
...  
Keyword(s):  
Bacterial Species ◽  
Xylose Reductase ◽  
Pentose Phosphate ◽  
Terpene Biosynthesis ◽  
Content Type ◽  
E Coli ◽  
Pathway Expression ◽  
Terpene Synthesis ◽  
Selection For

ABSTRACTTerpene synthesis in the majority of bacterial species, together with plant plastids, takes place via the 1-deoxy-d-xylulose 5-phosphate (DXP) pathway. The first step of this pathway involves the condensation of pyruvate and glyceraldehyde 3-phosphate by DXP synthase (Dxs), with one-sixth of the carbon lost as CO2. A hypothetical novel route from a pentose phosphate to DXP (nDXP) could enable a more direct pathway from C5sugars to terpenes and also circumvent regulatory mechanisms that control Dxs, but there is no enzyme known that can convert a sugar into its 1-deoxy equivalent. Employing a selection for complementation of adxsdeletion inEscherichia coligrown on xylose as the sole carbon source, we uncovered two candidate nDXP genes. Complementation was achieved either via overexpression of the wild-typeE. coliyajOgene, annotated as a putative xylose reductase, or via various mutations in the nativeribBgene.In vitroanalysis performed with purified YajO and mutant RibB proteins revealed that DXP was synthesized in both cases from ribulose 5-phosphate (Ru5P). We demonstrate the utility of these genes for microbial terpene biosynthesis by engineering the DXP pathway inE. colifor production of the sesquiterpene bisabolene, a candidate biodiesel. To further improve flux into the pathway from Ru5P, nDXP enzymes were expressed as fusions to DXP reductase (Dxr), the second enzyme in the DXP pathway. Expression of a Dxr-RibB(G108S) fusion improved bisabolene titers more than 4-fold and alleviated accumulation of intracellular DXP.

scholarly journals Probiotic Potential of a Novel Vitamin B2-Overproducing Lactobacillus plantarum Strain, HY7715, Isolated from Kimchi

2021 ◽  
Vol 11 (13) ◽  
pp. 5765
Author(s):  
Joo-Yun Kim ◽  
Eun-Jung Choi ◽  
Jae-Ho Lee ◽  
Myeong-Seok Yoo ◽  
Keon Heo ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Lactobacillus Plantarum ◽  
Probiotic Strain ◽  
Optimal Growth ◽  
Control Group ◽  
High Survival ◽  
Vitamin B2 ◽  
Riboflavin Deficiency

Vitamin B2, also known as riboflavin, is essential for maintaining human health. The purpose of this study was to isolate novel lactic acid bacteria that overproduce vitamin B2 and to validate their potential as probiotics. In this study, Lactobacillus plantarum HY7715 (HY7715) was selected among lactic acid bacteria isolated from Kimchi. HY7715 showed a very high riboflavin-producing ability compared to the control strain due to the high expression of ribA, ribB, ribC, ribH, and ribG genes. HY7715 produced 34.5 ± 2.41 mg/L of riboflavin for 24 h without consuming riboflavin in the medium under optimal growth conditions. It was able to produce riboflavin in an in vitro model of the intestinal environment. In addition, when riboflavin deficiency was induced in mice through nutritional restriction, higher levels of riboflavin were detected in plasma and urine in the HY7715 administration group than in the control group. HY7715 showed high survival rate in simulated gastrointestinal conditions and had antibiotic resistance below the cutoff MIC value suggested by the European Food Safety Authority; moreover, it did not cause hemolysis. In conclusion, HY7715 could be considered a beneficial probiotic strain for human and animal applications, suggesting that it could be a new alternative to address riboflavin deficiency.

Cell-free supernatants produced by lactic acid bacteria reduce Salmonella population in vitro

Microbiology ◽  
2021 ◽  
Vol 167 (11) ◽  
Author(s):  
Alberto Gonçalves Evangelista ◽  
Jessica Audrey Feijó Corrêa ◽  
João Vitor Garcia dos Santos ◽  
Eduardo Henrique Custódio Matté ◽  
Mônica Moura Milek ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Lactic Acid ◽  
Antimicrobial Resistance ◽  
Lactic Acid Bacteria ◽  
Type Species ◽  
Feed Additives ◽  
Poultry Feed ◽  
Content Type ◽  
Link Type

The genus Salmonella is closely associated with foodborne outbreaks and animal diseases, and reports of antimicrobial resistance in Salmonella species are frequent. Several alternatives have been developed to control this pathogen, such as cell-free supernatants (CFS). Our objective here was to evaluate the use of lactic acid bacteria (LAB) CFS against Salmonella in vitro. Seventeen strains of LAB were used to produce CFS, and their antimicrobial activity was screened towards six strains of Salmonella . In addition, CFS were also pH-neutralized and/or boiled. Those with the best results were lyophilized. MICs of lyophilized CFS were 11.25–22.5 g l–1. Freeze-dried CFS were also used to supplement swine and poultry feed (11.25 g kg–1) and in vitro simulated digestion of both species was performed, with Salmonella contamination of 5×106 and 2×105 c.f.u. g−1 of swine and poultry feed, respectively. In the antimicrobial screening, all acidic CFS were able to inhibit the growth of Salmonella . After pH neutralization, Lactobacillus acidophilus Llorente, Limosilactobacillus fermentum CCT 1629, Lactiplantibacillus plantarum PUCPR44, Limosilactobacillus reuteri BioGaia, Lacticaseibacillus rhamnosus ATCC 7469 and Pediococcus pentosaceus UM116 CFS were the only strains that partially maintained their antimicrobial activity and, therefore, were chosen for lyophilization. In the simulated swine digestion, Salmonella counts were reduced ≥1.78 log c.f.u. g–1 in the digesta containing either of the CFS. In the chicken simulation, a significant reduction was obtained with all CFS used (average reduction of 0.59±0.01 log c.f.u. ml–1). In general, the lyophilized CFS of L. fermentum CCT 1629, L. rhamnosus ATCC 7469 and L. acidophilus Llorente presented better antimicrobial activity. In conclusion, CFS show potential as feed additives to control Salmonella in animal production and may be an alternative to the use of antibiotics, minimizing problems related to antimicrobial resistance.

scholarly journals Analysis of Transcriptomic Response to SO 2 by Oenococcus oeni Growing in Continuous Culture

2021 ◽  
Author(s):  
Cristobal A. Onetto ◽  
Peter J. Costello ◽  
Radka Kolouchova ◽  
Charlotte Jordans ◽  
Jane McCarthy ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacterium ◽  
High Sensitivity ◽  
Malolactic Fermentation ◽  
Oenococcus Oeni ◽  
Low Ph ◽  
Transcriptomic Response ◽  
Content Type ◽  
Bacterium Species ◽  
High Ethanol

Malolactic fermentation is an indispensable step in the elaboration of most wines and is generally performed by Oenococcus oeni , a Gram-positive heterofermentative lactic acid bacterium species. While O. oeni is tolerant to many of the wine stresses, including low pH and high ethanol concentrations, it has high sensitivity to SO 2 , an antiseptic and antioxidant compound regularly used in winemaking.

Lactobacillus plantarum ZJ316 improves the quality of Stachys sieboldii Miq. pickle by inhibiting harmful bacteria growth and degrading nitrite, promoting the gut microbiota health in vitro

2022 ◽  
Author(s):  
Shu Ting Hang ◽  
Ling zhou Zeng ◽  
Jia run Han ◽  
Zhong qin Zhang ◽  
Qingqing Zhou ◽  
...  
Keyword(s):  
Quality Control ◽  
Lactic Acid ◽  
Lactobacillus Plantarum ◽  
Microbial Contamination ◽  
Nitrite Accumulation ◽  
Bacteria Growth ◽  
Lactobacillus Plantarum Zj316 ◽  
Stachys Sieboldii

Microbial contamination and nitrite accumulation are two major concerns on the quality control of fermented vegetables. In the present study, a lactic acid bacteria strain Lactobacillus plantarum ZJ316 (ZJ316) was...

scholarly journals In Vitro Evaluation of Probiotic Properties of Lactic Acid Bacteria Isolated from Some Traditionally Fermented Ethiopian Food Products

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Guesh Mulaw ◽  
Tesfaye Sisay Tessema ◽  
Diriba Muleta ◽  
Anteneh Tesfaye
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Bile Salt ◽  
Lactobacillus Plantarum ◽  
Pathogenic Bacteria ◽  
Survival Rates ◽  
Lactobacillus Paracasei ◽  
Probiotic Properties ◽  
Sequence Comparisons

Probiotics are live microorganisms which when consumed in large number together with a food promote the health of the consumer. The aim of this study was to evaluate in vitro probiotic properties of lactic acid bacteria (LAB) isolated from traditional Ethiopian fermented Teff injera dough, Ergo, and Kocho products. A total of 90 LAB were isolated, of which 4 (4.44%) isolates showed 45.35–97.11% and 38.40–90.49% survival rates at pH values (2, 2.5, and 3) for 3 and 6 h, in that order. The four acid-tolerant isolates were found tolerant to 0.3% bile salt for 24 h with 91.37 to 97.22% rate of survival. The acid-and-bile salt-tolerant LAB isolates were found inhibiting some food-borne test pathogenic bacteria to varying degrees. All acid-and-bile-tolerant isolates displayed varying sensitivity to different antibiotics. The in vitro adherence to stainless steel plates of the 4 screened probiotic LAB isolates were ranged from 32.75 to 36.30% adhesion rate. The four efficient probiotic LAB isolates that belonged to Lactobacillus species were identified to the strain level using 16S rDNA gene sequence comparisons and, namely, were Lactobacillus plantarum strain CIP 103151, Lactobacillus paracasei subsp. tolerans strain NBRC 15906, Lactobacillus paracasei strain NBRC 15889, and Lactobacillus plantarum strain JCM 1149. The four Lactobacillus strains were found to be potentially useful to produce probiotic products.

scholarly journals RNA G-Quadruplex Structures Mediate Gene Regulation in Bacteria

mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiaolong Shao ◽  
Weitong Zhang ◽  
Mubarak Ishaq Umar ◽  
Hei Yuen Wong ◽  
Zijing Seng ◽  
...  
Keyword(s):  
Gene Regulation ◽  
Cell Envelope ◽  
Bacterial Species ◽  
Virulence Gene ◽  
Content Type ◽  
Cellular Processes ◽  
Wide Range ◽  
G Quadruplex ◽  
Eukaryotic Organisms

ABSTRACT Guanine (G)-rich sequences in RNA can fold into diverse RNA G-quadruplex (rG4) structures to mediate various biological functions and cellular processes in eukaryotic organisms. However, the presence, locations, and functions of rG4s in prokaryotes are still elusive. We used QUMA-1, an rG4-specific fluorescent probe, to detect rG4 structures in a wide range of bacterial species both in vitro and in live cells and found rG4 to be an abundant RNA secondary structure across those species. Subsequently, to identify bacterial rG4 sites in the transcriptome, the model Escherichia coli strain and a major human pathogen, Pseudomonas aeruginosa, were subjected to recently developed high-throughput rG4 structure sequencing (rG4-seq). In total, 168 and 161 in vitro rG4 sites were found in E. coli and P. aeruginosa, respectively. Genes carrying these rG4 sites were found to be involved in virulence, gene regulation, cell envelope synthesis, and metabolism. More importantly, biophysical assays revealed the formation of a group of rG4 sites in mRNAs (such as hemL and bswR), and they were functionally validated in cells by genetic (point mutation and lux reporter assays) and phenotypic experiments, providing substantial evidence for the formation and function of rG4s in bacteria. Overall, our study uncovers important regulatory functions of rG4s in bacterial pathogenicity and metabolic pathways and strongly suggests that rG4s exist and can be detected in a wide range of bacterial species. IMPORTANCE G-quadruplex in RNA (rG4) mediates various biological functions and cellular processes in eukaryotic organisms. However, the presence, locations, and functions of rG4 are still elusive in prokaryotes. Here, we found that rG4 is an abundant RNA secondary structure across a wide range of bacterial species. Subsequently, the transcriptome-wide rG4 structure sequencing (rG4-seq) revealed that the model E. coli strain and a major human pathogen, P. aeruginosa, have 168 and 161 in vitro rG4 sites, respectively, involved in virulence, gene regulation, cell envelope, and metabolism. We further verified the regulatory functions of two rG4 sites in bacteria (hemL and bswR). Overall, this finding strongly suggests that rG4s play key regulatory roles in a wide range of bacterial species.

scholarly journals Ethylphenol Formation byLactobacillus plantarum: Identification of the Enzyme Involved in the Reduction of Vinylphenols

2018 ◽  
Vol 84 (17) ◽  
Author(s):  
Laura Santamaría ◽  
Inés Reverón ◽  
Félix López de Felipe ◽  
Blanca de las Rivas ◽  
Rosario Muñoz
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Bacterial Species ◽  
Alcoholic Beverages ◽  
Genetic Identification ◽  
Detection Methods ◽  
Fermented Foods ◽  
Content Type ◽  
Volatile Phenol ◽  
Off Flavors

ABSTRACTEthylphenols are strong odorants produced by microbial activity that are described as off flavors in several foods.Lactobacillus plantarumis 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. In this study, the involvement in vinylphenol reduction of a gene encoding a putative reductase (lp_3125) was confirmed by the absence of reduction activity in the Δlp_3125knockout mutant. The protein encoded bylp_3125, VprA, was recombinantly produced inEscherichia coli. VprA was assayed against vinylphenols (4-vinylphenol, 4-vinylcatechol, and 4-vinylguaiacol), and all were reduced to their corresponding ethylphenols (4-ethylphenol, 4-ethylcatechol, and 4-ethylguaiacol). PCR and high-performance liquid chromatography (HPLC) detection methods revealed that the VprA reductase is not widely distributed among the lactic acid bacteria studied and that only the bacteria possessing thevprAgene were able to produce ethylphenol from vinylphenol. However, all the species belonging to theL. plantarumgroup were ethylphenol producers. The identification of theL. plantarumVprA protein involved in hydroxycinnamate degradation completes the route of degradation of these compounds in lactic acid bacteria.IMPORTANCEThe presence of volatile phenols is considered a major organoleptic defect of several fermented alcoholic beverages. The biosynthesis of these compounds has been mainly associated withBrettanomyces/Dekkerayeasts. However, the potential importance of lactic acid bacteria in volatile phenol spoilage is emphasized by reports describing a faster ethylphenol production by these bacteria than by yeasts. The genetic identification of the bacterial vinylphenol reductase involved in volatile phenol production provides new insights into the role of lactic acid bacteria in the production of these off flavors. The development of a molecular method for the detection of ethylphenol-producing bacteria could be helpful to design strategies to reduce the bacterial production of vinylphenols in fermented foods.

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