A synbiotic mixture of selected oligosaccharides and bifidobacteria assists murine gut microbiota restoration following antibiotic challenge.

Background: Typically, animal models studying gastrointestinal microbiotas compromised in early life have employed either germ-free animals or mice treated with a cocktail of antibiotics. Such studies intend to mimic scenarios of infants born by caesarean section and/or subjected to antibiotic treatment. However, the antibiotics used in these studies are rarely prescribed to infants.

Quantitative Physiology and Proteome Adaptations of Bifidobacterium breve NRBB57 at Near-Zero Growth Rates.

In natural environments, nutrients are usually scarce, causing microorganisms to grow slowly while staying metabolically active. These natural conditions can be simulated using retentostat cultivations. The present study describes the physiological and proteome adaptations of the probiotic Bifidobacterium breve NRBB57 from high (0.

Broad Purpose Vector for Site-Directed Insertional Mutagenesis in .

Members of the genus are notoriously recalcitrant to genetic manipulation due to their extensive and variable repertoire of Restriction-Modification (R-M) systems. Non-replicating plasmids are currently employed to achieve insertional mutagenesis in . One of the limitations of using such insertion vectors is the presence within their sequence of various restriction sites, making them sensitive to the activity of endogenous restriction endonucleases encoded by the target strain.

Bifidobacterium Transformation.

The protocol presented in this chapter describes a generic method for electrotransformation of Bifidobacterium spp., outlining a technique that is ideal for conferring selective properties onto strains as well as allowing the user to introduce or knock out/in selected genes for phenotypic characterization purposes. We have generalized on the plasmid chosen for transformation and antibiotic selection marker, but the protocol is versatile in this respect and we are able to achieve transformation efficiencies up to 10 transformants/μg of DNA.

Breast milk urea as a nitrogen source for urease positive Bifidobacterium infantis.

Human milk stimulates a health-promoting gut microbiome in infants. However, it is unclear how the microbiota salvages and processes its required nitrogen from breast milk. Human milk nitrogen sources such as urea could contribute to the composition of this early life microbiome.

Fosters the Growth of Butyrate-Producing in the Presence of Lactose and Total Human Milk Carbohydrates.

The development of infant gut microbiota is strongly influenced by nutrition. Human milk oligosaccharides (HMOSs) in breast milk selectively promote the growth of glycan-degrading microbes, which lays the basis of the microbial network. In this study, we investigated the trophic interaction between and the butyrate-producing in the presence of early-life carbohydrates.

Draft Genome Sequence of Streptococcus thermophilus C106, a Dairy Isolate from an Artisanal Cheese Produced in the Countryside of Ireland.

The lactic acid bacterium Streptococcus thermophilus is widely used for the fermentation of dairy products. Here, we present the draft genome sequence of S. thermophilus C106 isolated from an artisanal cheese produced in the countryside of Ireland.

Carbohydrate availability regulates virulence gene expression in Streptococcus suis.

Streptococcus suis is a major bacterial pathogen of young pigs causing worldwide economic problems for the pig industry. S. suis is also an emerging pathogen of humans.

Transcriptome signatures of class I and III stress response deregulation in Lactobacillus plantarum reveal pleiotropic adaptation.

Background: To cope with environmental challenges bacteria possess sophisticated defense mechanisms that involve stress-induced adaptive responses. The canonical stress regulators CtsR and HrcA play a central role in the adaptations to a plethora of stresses in a variety of organisms. Here, we determined the CtsR and HrcA regulons of the lactic acid bacterium Lactobacillus plantarum WCFS1 grown under reference (28°C) and elevated (40°C) temperatures, using ctsR, hrcA, and ctsR-hrcA deletion mutants.

Impact of Lactobacillus plantarum sortase on target protein sorting, gastrointestinal persistence, and host immune response modulation.

Sortases are transpeptidases that couple surface proteins to the peptidoglycan of Gram-positive bacteria, and several sortase-dependent proteins (SDPs) have been demonstrated to be crucial for the interactions of pathogenic and nonpathogenic bacteria with their hosts. Here, we studied the role of sortase A (SrtA) in Lactobacillus plantarum WCFS1, a model Lactobacillus for probiotic organisms. An isogenic srtA deletion derivative was constructed which did not show residual SrtA activity.

Impact of 4 Lactobacillus plantarum capsular polysaccharide clusters on surface glycan composition and host cell signaling.

Background: Bacterial cell surface-associated polysaccharides are involved in the interactions of bacteria with their environment and play an important role in the communication between pathogenic bacteria and their host organisms. Cell surface polysaccharides of probiotic species are far less well described. Therefore, improved knowledge on these molecules is potentially of great importance to understand the strain-specific and proposed beneficial modes of probiotic action.

Genome-wide prediction and validation of sigma70 promoters in Lactobacillus plantarum WCFS1.

Background: In prokaryotes, sigma factors are essential for directing the transcription machinery towards promoters. Various sigma factors have been described that recognize, and bind to specific DNA sequence motifs in promoter sequences. The canonical sigma factor σ(70) is commonly involved in transcription of the cell's housekeeping genes, which is mediated by the conserved σ(70) promoter sequence motifs.

Transcriptomes reveal genetic signatures underlying physiological variations imposed by different fermentation conditions in Lactobacillus plantarum.

Lactic acid bacteria (LAB) are utilized widely for the fermentation of foods. In the current post-genomic era, tools have been developed that explore genetic diversity among LAB strains aiming to link these variations to differential phenotypes observed in the strains investigated. However, these genotype-phenotype matching approaches fail to assess the role of conserved genes in the determination of physiological characteristics of cultures by environmental conditions.

Comparative analysis of Lactobacillus plantarum WCFS1 transcriptomes by using DNA microarray and next-generation sequencing technologies.

RNA sequencing is starting to compete with the use of DNA microarrays for transcription analysis in eukaryotes as well as in prokaryotes. The application of RNA sequencing in prokaryotes requires additional steps in the RNA preparation procedure to increase the relative abundance of mRNA and cannot employ the poly(T)-primed approach in cDNA synthesis. In this study, we aimed to validate the use of RNA sequencing (direct cDNA sequencing and 3'-untranslated region [UTR] sequencing) using Lactobacillus plantarum WCFS1 as a model organism, employing its established microarray platform as a reference.

Functional analysis of the role of CggR (central glycolytic gene regulator) in Lactobacillus plantarum by transcriptome analysis.

The level of the central glycolytic gene regulator (CggR) was engineered in Lactobacillus plantarum NC8 and WCFS1 by overexpression and in-frame mutation of the cggR gene in order to evaluate its regulatory role on the glycolytic gap operon and the glycolytic flux. The repressor role of CggR on the gap operon was indicated through identification of a putative CggR operator and transcriptome analysis, which coincided with decreased growth rate and glycolytic flux when cggR was overexpressed in NC8 and WCFS1. The mutation of cggR did not affect regulation of the gap operon, indicating a more prominent regulatory role of CggR on the gap operon under other conditions than tested (e.

Indigenous and environmental modulation of frequencies of mutation in Lactobacillus plantarum.

Reliability of microbial (starter) strains in terms of quality, functional properties, growth performance, and robustness is essential for industrial applications. In an industrial fermentation process, the bacterium should be able to successfully withstand various adverse conditions during processing, such as acid, osmotic, temperature, and oxidative stresses. Besides the evolved defense mechanisms, stress-induced mutations participate in adaptive evolution for survival under stress conditions.

Lifestyle of Lactobacillus plantarum in the mouse caecum.

Lactobacillus plantarum is a common inhabitant of mammalian gastrointestinal tracts. Strains of L. plantarum are also marketed as probiotics intended to confer beneficial health effects upon delivery to the human gut.

Large intergenic cruciform-like supermotifs in the Lactobacillus plantarum genome.

Twenty-four Lactobacillus plantarum supermotifs (LPSMs) with lengths from approximately 800 to 1,000 nucleotides were identified in the L. plantarum genome. LPSMs were conserved in other L.

Functional analysis of four bile salt hydrolase and penicillin acylase family members in Lactobacillus plantarum WCFS1.

Bile salts play an important role in the digestion of lipids in vertebrates and are synthesized and conjugated to either glycine or taurine in the liver. Following secretion of bile salts into the small intestine, intestinal microbes are capable of deconjugating the glycine or taurine from the bile salts, using an enzyme called bile salt hydrolase (Bsh). Intestinal lactobacilli are regarded as major contributors to bile salt hydrolysis in vivo.

Cre-lox-based system for multiple gene deletions and selectable-marker removal in Lactobacillus plantarum.

The classic strategy to achieve gene deletion variants is based on double-crossover integration of nonreplicating vectors into the genome. In addition, recombination systems such as Cre-lox have been used extensively, mainly for eukaryotic organisms. This study presents the construction of a Cre-lox-based system for multiple gene deletions in Lactobacillus plantarum that could be adapted for use on gram-positive bacteria.

Spatial and temporal expression of Lactobacillus plantarum genes in the gastrointestinal tracts of mice.

Lactobacillus plantarum is a common inhabitant of mammalian gastrointestinal tracts, and L. plantarum strain WCFS1 is a human isolate with a known genome sequence. L.

Introducing glutathione biosynthetic capability into Lactococcus lactis subsp. cremoris NZ9000 improves the oxidative-stress resistance of the host.

This study describes how a metabolic engineering approach can be used to improve bacterial stress resistance. Some Lactococcus lactis strains are capable of taking up glutathione, and the imported glutathione protects this organism against H(2)O(2)-induced oxidative stress. L.

Development and characterization of a subtilin-regulated expression system in Bacillus subtilis: strict control of gene expression by addition of subtilin.

A system for subtilin-regulated gene expression (SURE) in Bacillus subtilis that is based on the regulatory module involved in cell-density-dependent control of the production of subtilin is described. An integration vector for introduction of the essential sensor-regulator couple spaRK into the amyE locus of the B. subtilis chromosome and a B.

Functional analysis of three plasmids from Lactobacillus plantarum.

Lactobacillus plantarum WCFS1 harbors three plasmids, pWCFS101, pWCFS102, and pWCFS103, with sizes of 1,917, 2,365, and 36,069 bp, respectively. The two smaller plasmids are of unknown function and contain replication genes that are likely to function via the rolling-circle replication mechanism. The host range of the pWCFS101 replicon includes Lactobacillus species and Lactococcus lactis, while that of the pWCFS102 replicon also includes Carnobacterium maltaromaticum and Bacillus subtilis.

High-level acetaldehyde production in Lactococcus lactis by metabolic engineering.

Efficient conversion of glucose to acetaldehyde is achieved by nisin-controlled overexpression of Zymomonas mobilis pyruvate decarboxylase (pdc) and Lactococcus lactis NADH oxidase (nox) in L. lactis. In resting cells, almost 50% of the glucose consumed could be redirected towards acetaldehyde by combined overexpression of pdc and nox under anaerobic conditions.