Long-term intake of Lactobacillus helveticus enhances bioavailability of omega-3 fatty acids in the mouse retina.

Omega-3 (n-3) polyunsaturated fatty acids (PUFAs), particularly docosahexaenoic acid (DHA), are required for the structure and function of the retina. Several observational studies indicate that consumption of a diet with relatively high levels of n-3 PUFAs, such as those provided by fish oils, has a protective effect against the development of age-related macular degeneration. Given the accumulating evidence showing the role of gut microbiota in regulating retinal physiology and host lipid metabolism, we evaluated the potential of long-term dietary supplementation with the Gram-positive bacterium Lactobacillus helveticus strain VEL12193 to modulate the retinal n-3 PUFA content.

Significant influence of four highly conserved amino-acids in lipochaperon-active sHsps on the structure and functions of the Lo18 protein.

To cope with environmental stresses, bacteria have developed different strategies, including the production of small heat shock proteins (sHSP). All sHSPs are described for their role as molecular chaperones. Some of them, like the Lo18 protein synthesized by Oenococcus oeni, also have the particularity of acting as a lipochaperon to maintain membrane fluidity in its optimal state following cellular stresses.

Membrane vesicles released by Lacticaseibacillus casei BL23 inhibit the biofilm formation of Salmonella Enteritidis.

Biofilms represent a major concern in the food industry and healthcare. The use of probiotic bacteria and their derivatives as an alternative to conventional treatments to fight biofilm development is a promising option that has provided convincing results in the last decades. Recently, membrane vesicles (MVs) produced by probiotics have generated considerable interest due to the diversity of roles they have been associated with.

Spontaneous Prophage Induction Contributes to the Production of Membrane Vesicles by the Gram-Positive Bacterium BL23.

The formation of membrane vesicles (MVs) by Gram-positive bacteria has gained increasing attention over the last decade. Recently, models of vesicle formation have been proposed and involve the digestion of the cell wall by prophage-encoded or stress-induced peptidoglycan (PG) hydrolases and the inhibition of PG synthesis by β-lactam antibiotics. The impact of these mechanisms on vesicle formation is largely dependent on the strain and growth conditions.

Lactobacillus stress protein GroEL prevents colonic inflammation.

Background: We previously showed that supernatants of Lactobacillus biofilms induced an anti-inflammatory response by affecting the secretion of macrophage-derived cytokines, which was abrogated upon immunodepletion of the stress protein GroEL.

Methods: We purified GroEL from L. reuteri and analysed its anti-inflammatory properties in vitro in human macrophages isolated from buffy coats, ex vivo in explants from human biopsies and in vivo in a mouse model of DSS induced intestinal inflammation.

Intestinal release of biofilm-like microcolonies encased in calcium-pectinate beads increases probiotic properties of Lacticaseibacillus paracasei.

In this study, we show that calcium pectinate beads (CPB) allow the formation of 20 µm spherical microcolonies of the probiotic bacteria Lacticaseibacillus paracasei (formerly designated as Lactobacillus paracasei) ATCC334 with a high cell density, reaching more than 10 log (CFU/g). The bacteria within these microcolonies are well structured and adhere to a three-dimensional network made of calcium-pectinate through the synthesis of extracellular polymeric substances (EPS) and thus display a biofilm-like phenotype, an attractive property for their use as probiotics. During bacterial development in the CPB, a coalescence phenomenon arises between neighboring microcolonies accompanied by their peripheral spatialization within the bead.

Inhibition of mitophagy drives macrophage activation and antibacterial defense during sepsis.

Mitochondria have emerged as key actors of innate and adaptive immunity. Mitophagy has a pivotal role in cell homeostasis, but its contribution to macrophage functions and host defense remains to be delineated. Here, we showed that lipopolysaccharide (LPS) in combination with IFN-γ inhibited PINK1-dependent mitophagy in macrophages through a STAT1-dependent activation of the inflammatory caspases 1 and 11.

Resveratrol Favors Adhesion and Biofilm Formation of Strain ATCC334.

Bacterial strains of the Lactobacillaceae family are widely used as probiotics for their multifaceted potential beneficial properties. However, no official recommendations for their clinical use exist since, in many cases, oral administrations of these bacteria displayed limited beneficial effects in human. Additional research is thus needed to improve the efficiency of existing strains with strong potential.

Disentangling the effect of host genetics and gut microbiota on resistance to an intestinal parasite.

Resistance to infection is a multifactorial trait, and recent work has suggested that the gut microbiota can also contribute to resistance. Here, we performed a fecal microbiota transplant to disentangle the contribution of the gut microbiota and host genetics as drivers of resistance to the intestinal nematode Heligmosomoides polygyrus. We transplanted the microbiota of a strain of mice (SJL), resistant to H.

The Phenotypic Analysis of Mutants Reveals a Potential Role for in Cryotolerance.

Small heat shock proteins (sHSPs) are ubiquitous, low molecular weight (MW) proteins that share a conserved alpha-crystallin domain. sHSPs oligomers exhibit chaperon-like activities by interacting with unfolded substrates, thereby preventing their aggregation and precipitation. Unlike most lactobacilli, which have single genes, three different sHSP-encoding genes, i.

Resveratrol-Induced Xenophagy Promotes Intracellular Bacteria Clearance in Intestinal Epithelial Cells and Macrophages.

Autophagy is a lysosomal degradation process that contributes to host immunity by eliminating invasive pathogens and the modulating inflammatory response. Several infectious and immune disorders are associated with autophagy defects, suggesting that stimulation of autophagy in these diseases should be beneficial. Here, we show that resveratrol is able to boost xenophagy, a selective form of autophagy that target invasive bacteria.

Production of the small heat shock protein Lo18 from Oenococcus oeni in Lactococcus lactis improves its stress tolerance.

Lactococcus lactis is a lactic acid bacterium widely used in cheese and fermented milk production. During fermentation, L. lactis is subjected to acid stress that impairs its growth.

Biofilms of Lactobacillus plantarum and Lactobacillus fermentum: Effect on stress responses, antagonistic effects on pathogen growth and immunomodulatory properties.

Few studies have extensively investigated probiotic functions associated with biofilms. Here, we show that strains of Lactobacillus plantarum and Lactobacillus fermentum are able to grow as biofilm on abiotic surfaces, but the biomass density differs between strains. We performed microtiter plate biofilm assays under growth conditions mimicking to the gastrointestinal environment.

The biofilm mode of life boosts the anti-inflammatory properties of Lactobacillus.

The predominant form of life for microorganisms in their natural habitats is the biofilm mode of growth. The adherence and colonization of probiotic bacteria are considered as essential factors for their immunoregulatory function in the host. Here, we show that Lactobacillus casei ATCC334 adheres to and colonizes the gut of zebrafish larvae.

Tyrosine-containing peptides are precursors of tyramine produced by Lactobacillus plantarum strain IR BL0076 isolated from wine.

Background: Biogenic amines are molecules with allergenic properties. They are found in fermented products and are synthesized by lactic acid bacteria through the decarboxylation of amino acids present in the food matrix. The concentration of biogenic amines in fermented foodstuffs is influenced by many environmental factors, and in particular, biogenic amine accumulation depends on the quantity of available precursors.

The oligomer plasticity of the small heat-shock protein Lo18 from Oenococcus oeni influences its role in both membrane stabilization and protein protection.

The ability of the small Hsp (heat-shock protein) Lo18 from Oenococcus oeni to modulate the membrane fluidity of liposomes or to reduce the thermal aggregation of proteins was studied as a function of the pH in the range 5-9. We have determined by size-exclusion chromatography and analytical ultracentrifugation that Lo18 assembles essentially as a 16-mer at acidic pH. Its quaternary structure evolves to a mixture of lower molecular mass oligomers probably in dynamic equilibrium when the pH increases.

Inactivation of the ftsH gene of Lactobacillus plantarum WCFS1: effects on growth, stress tolerance, cell surface properties and biofilm formation.

FtsH proteins are ubiquitous membrane-bound, ATP-dependent metalloproteases of the AAA family. In eubacteria, FtsH is involved in protein quality control under stress conditions. Lactobacillus plantarum is a widespread lactic acid bacterium that is encountered in several fermented food, including dairy products, vegetables and meat.

Inactivation of a small heat shock protein affects cell morphology and membrane fluidity in Lactobacillus plantarum WCFS1.

A small heat shock gene of Lactobacillus plantarum strain WCFS1 was deleted using a Cre-lox based system. Compared to the wild type, the ∆hsp 18.55 mutant strain displayed a similar growth rate when cultivated either under optimal temperature or under different stress conditions such as heat, low pH and salt stress.

Distinct amino acids of the Oenococcus oeni small heat shock protein Lo18 are essential for damaged protein protection and membrane stabilization.

The small heat shock protein (smHsp) Lo18 from lactic acid bacteria Oenococcus oeni reduces in vitro thermal aggregation of proteins and modulates the membrane fluidity of native liposomes. An absence of information relating to the way in which the smHsp demonstrates a stabilizing effect for both proteins and membranes prompted this study. We expressed three Lo18 proteins with amino acid substitutions in Escherichia coli to investigate their ability to prevent E.

Characterization of the CtsR stress response regulon in Lactobacillus plantarum.

Lactobacillus plantarum ctsR was characterized. ctsR was found to be cotranscribed with clpC and induced in response to various abiotic stresses. ctsR deletion conferred a heat-sensitive phenotype with peculiar cell morphological features.

Interactions in dual species biofilms between Listeria monocytogenes EGD-e and several strains of Staphylococcus aureus.

Six environmental isolates of Staphylococcus aureus and one collection strain were investigated for their ability to form monospecies biofilms and dual species biofilms with Listeria monocytogenes EGD-e on stainless steel coupons. All isolates were able to grow as biofilms but their ability to form monospecies biofilms differed. The population of L.

Listeria monocytogenes EGD-e biofilms: no mushrooms but a network of knitted chains.

Listeria monocytogenes is a food pathogen that can attach on most of the surfaces encountered in the food industry. Biofilms are three-dimensional microbial structures that facilitate the persistence of pathogens on surfaces, their resistance toward antimicrobials, and the final contamination of processed goods. So far, little is known about the structural dynamics of L.

Characteristics and frequency of detection of fecal Listeria monocytogenes shed by livestock, wildlife, and humans.

Listeria monocytogenes is a facultative intracellular pathogen that can be carried asymptomatically in various animals and can be shed in feces. We investigated the prevalence and characteristics of L. monocytogenes isolated from livestock, wildlife, and human potential sources of contamination in 2 areas in Ontario, Canada.

Agr system of Listeria monocytogenes EGD-e: role in adherence and differential expression pattern.

In this study, we investigated the agrBDCA operon in the pathogenic bacterium Listeria monocytogenes EGD-e. In-frame deletion of agrA and agrD resulted in an altered adherence and biofilm formation on abiotic surfaces, suggesting the involvement of the agr system of L. monocytogenes during the early stages of biofilm formation.

Distribution and characteristics of Listeria monocytogenes isolates from surface waters of the South Nation River watershed, Ontario, Canada.

Listeria monocytogenes is a facultative intracellular pathogen thought to be widely distributed in the environment. We investigated the prevalence and characteristics of L. monocytogenes isolates from surface waters derived from catchments within the South Nation River watershed (Ontario, Canada).