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Microbiology Spectrum Aug 2022The LuxS enzyme plays a key role in both quorum sensing (QS) and the regulation of bacterial growth. It catalyzes the production of autoinducer-2 (AI-2) signaling...
AI-2/LuxS Quorum Sensing System Promotes Biofilm Formation of Lactobacillus rhamnosus GG and Enhances the Resistance to Enterotoxigenic Escherichia coli in Germ-Free Zebrafish.
The LuxS enzyme plays a key role in both quorum sensing (QS) and the regulation of bacterial growth. It catalyzes the production of autoinducer-2 (AI-2) signaling molecule, which is a component of the methyl cycle and methionine metabolism. This study aimed at investigating the differences between the Lactobacillus rhamnosus GG (LGG) wild-type strain (WT) and its mutant (ΔluxS) during biofilm formation and when resisting to inflammation caused by Enterotoxigenic Escherichia coli (ETEC) in germ-free zebrafish. Our results suggest that in the absence of when LGG was knocked out, biofilm formation, extracellular polysaccharide secretion and adhesion were all compromised. Addition of synthetic AI-2 indeed rescued, at least partially, the deficiencies observed in the mutant strain. The colonizing and immunomodulatory function in WT versus ΔluxS mutants were further studied in a germ-free zebrafish model. The concentration of AI-2 signaling molecules decreased sharply in zebrafish infected with the ΔluxS. At the same time, compared with the ΔluxS, the wild-type strain could colonize the germ-free zebrafish more effectively. Our transcriptome results suggest that genes involved in immunity, signal transduction, and cell adhesion were downregulated in zebrafish infected with ΔluxS and WT. In the WT, the immune system of germ-free zebrafish was activated more effectively through the MAPK and NF-κB pathway, and its ability to fight the infection against ETEC was increased. Together, our results demonstrate that the AI-2/LuxS system plays an important role in biofilm formation to improve LGG and alleviate inflammation caused by ETEC in germ-free zebrafish. Lactobacillus rhamnosus GG is a widely used probiotic to improve host intestinal health, promote growth, reduce diarrhea, and modulate immunity. In recent years, the bacterial quorum sensing system has attracted much attention; however, there has not been much research on the effect of the LuxS/AI-2 quorum sensing system of on bacteriostasis, microbial ecology balance, and immune regulation in intestine. In this study, we used germ-free zebrafish as an animal model to compare the differences between wild-type and mutant strains. We showed how AI-2/LuxS QS affects the release of AI-2 and how QS regulates the colonization, EPS synthesis and biofilm formation of LGG. This study provides an idea for the targeted regulation of animal intestinal health with probiotics by controlling bacteria quorum sensing system.
Topics: Animals; Bacterial Proteins; Biofilms; Carbon-Sulfur Lyases; Enterotoxigenic Escherichia coli; Gene Expression Regulation, Bacterial; Inflammation; Lacticaseibacillus rhamnosus; Quorum Sensing; Zebrafish
PubMed: 35700135
DOI: 10.1128/spectrum.00610-22 -
Nutrients Nov 2021Probiotics can prevent obesity and related metabolic complications. In our study, the protective effect and molecular mechanism of JL1 (separated from the feces of...
Probiotics can prevent obesity and related metabolic complications. In our study, the protective effect and molecular mechanism of JL1 (separated from the feces of healthy infants) on high-fat diet mice were investigated. After 10 weeks of dietary intervention with JL1 intervention, the body weight of the JL1 group (23.78 g) was significantly lower than that of the HFD group (26.59 g, < 0.05) and the liver index was reduced. Serum biochemical analysis showed that the TC, TG and LDL-C contents of JL1 group mice were significantly decreased ( < 0.05). Histological images of the mice livers showed that the degree of lipid action and damage of hepatic cells were improved. JL1 activated the AMPK pathway, and reduced the gene expression of PPAR-γ, LXR-α and SREBP-1C. In addition, the protein expression of PPAR-γ and LXR-α were reduced. After dietary intervention with JL1, the concentration of acetic acid, propionic acid, and butyric acid were increased significantly, especially the concentration of butyric acid, which was 63.16% higher than that of the HFD group ( < 0.05). In conclusion, this study provided a theoretical reference for the development and application of probiotics derived from healthy infant feces in health products and functional foods.
Topics: Animals; Anticholesteremic Agents; Body Weight; Cytokines; Fatty Acids; Gene Expression Regulation; Inflammation Mediators; Lacticaseibacillus rhamnosus; Lipids; Liver; Male; Mice, Inbred C57BL; Obesity; Organ Size; RNA, Messenger; Mice
PubMed: 34836242
DOI: 10.3390/nu13113989 -
Pediatric Research Jun 2022Different microorganisms from the environment will begin to colonise the infant during and immediately after the delivery. It could be advantageous to influence the...
BACKGROUND
Different microorganisms from the environment will begin to colonise the infant during and immediately after the delivery. It could be advantageous to influence the microbiome early on by giving infants probiotic bacteria. The aim of the study was to investigate the tolerance of two probiotic lactobacilli in infants. The effect on the microbiota was also followed.
METHODS
Thirty-six healthy infants, aged 4-83 days at the start of the study, were given a daily supplementation of probiotics (Lactiplantibacillus plantarum HEAL9 and Lacticaseibacillus rhamnosus 271, 10 CFU (colony-forming units)) or placebo for 8 weeks. Adverse events, growth parameters, the faecal microbiome and intestinal performance were followed.
RESULTS
No differences between the groups in growth parameters, adverse events and intestinal performance were observed. The faecal levels of L. plantarum, L. rhamnosus and lactobacilli increased after the intake of probiotics and were significantly higher compared with the placebo group after 4 and 8 weeks of intake. The faecal microbial diversity was similar in the two groups at the end of the study.
CONCLUSIONS
The intervention with the probiotic formulation was well tolerated and increased the level of lactobacilli in the intestine. The developed probiotic formulation will be further evaluated for clinical efficacy in infants.
IMPACT
New data for the development of the gut function and the microbiome in breastfed and/or formula-fed young infants over time and the effect of adding two probiotic strains are presented. Lactiplantibacillus plantarum is a species that seldom has been analysed in infants, but it could be detected in 25% of the subjects before administration (mean age 41 days). Lactiplantibacillus plantarum and L. rhamnosus establish well in the intestine of infants and are well tolerated. The microbiota was positively affected by the intake of probiotics.
Topics: Adult; Feces; Humans; Infant; Lactobacillus; Lacticaseibacillus rhamnosus; Microbiota; Probiotics
PubMed: 34429515
DOI: 10.1038/s41390-021-01678-1 -
Frontiers in Immunology 2022Early weaning-induced stress impairs the intestinal barrier function and adversely affects the health of piglet. Probiotics can be used to prevent and treat various...
BACKGROUND
Early weaning-induced stress impairs the intestinal barrier function and adversely affects the health of piglet. Probiotics can be used to prevent and treat various intestinal diseases. GG (LGG) has an LuxS/AI-2 quorum sensing (QS) system that senses environmental changes through chemical signaling molecules. The aim of the study was to explore whether mutant affects the protective role of LGG in the gut barrier of weaned piglets by comparing the mutant (ΔluxS) with its wild-type (WT).
METHODS
Newborn piglets were orally administered with WT and ΔluxS at dosage of 10 CFU, respectively. Accordingly, newborn piglets in the Con group were orally administered with PBS. Piglets were weaned on day 21 and euthanized on day 24, three days following weaning.
RESULTS
Supplementation of ΔluxS in advance significantly boosted the relative abundances of healthy microbes (including , , and ). WT and ΔluxS maintain intestinal barrier function mainly by promoting intestinal villus to crypt ratio (VCR), occludin protein expression and mucus secretion (<0.05). Furthermore, LGG reduces pro-inflammatory mediators by inhibiting TLR4 and MAPK signal transduction (<0.05).
CONCLUSION
Both WT and ΔluxS were shown to resist weaning stress by enhancing the intestinal barrier function of piglets. It has to be said that the ability of ΔluxS to maintain intestinal tissue morphology and promote mucus secretion significantly decreased compared with that of WT.
Topics: Swine; Animals; Lacticaseibacillus rhamnosus; Weaning; Probiotics; Quorum Sensing; Inflammation
PubMed: 36569920
DOI: 10.3389/fimmu.2022.1080789 -
BMC Microbiology Jan 2023Foodborne pathogens and spoilage bacteria survived in the biofilm pose a serious threat to food safety and human health. It is urgent to find safe and effective methods...
BACKGROUND
Foodborne pathogens and spoilage bacteria survived in the biofilm pose a serious threat to food safety and human health. It is urgent to find safe and effective methods to control the planktonic bacteria as well as the biofilm formation. Substances with antibacterial and antibiofilm activity found in lactic acid bacteria were mainly metabolites secreted in the cell-free supernatant. Previously, Lacticaseibacillus rhamnosus YT was isolated because its cell pellets displayed distinguished antibacterial activity under neutral conditions. This study aimed to investigate the antibacterial and antibiofilm properties of the L. rhamnosus YT cells and its crude cell-surface extract.
RESULTS
The antibacterial activity of the L. rhamnosus YT cells constantly increased with cells growth and reached the peak value after the cells grew into stationary phase. After cocultivation with the L. rhamnosus YT cells, the biofilm formation of B. subtilis and S. enterica was reduced. The antibacterial activity of the L. rhamnosus YT cells was varied along with various culture conditions (carbon sources, nitrogen sources, medium pH and cultural temperatures) and the antibacterial intensity (antibacterial activity per cell) was disproportional to the biomass. Furthermore, the cell-surface extract was isolated and displayed broad antimicrobial spectrum with a bacteriostatic mode of action. The antibiofilm activity of the extract was concentration-dependent. In addition, the extract was stable to physicochemical treatments (heat, pH and protease). The extract performed favorable emulsifying property which could reduce the water surface tension from 72.708 mN/m to 51.011 mN/m and the critical micelle concentration (CMC) value was 6.88 mg/mL. Besides, the extract was also able to emulsify hydrocarbon substrates with the emulsification, index (E24) ranged from 38.55% (for n-hexane) to 53.78% (for xylene). The E24 for xylene/extract emulsion was merely decreased by 5.77% after standing for 120 h. The main components of the extract were polysaccharide (684.63 μg/mL) and protein (120.79 μg/mL).
CONCLUSION
The properties of the extract indicated that it might be a kind of biosurfactant. These data suggested that L. rhamnosus YT and the cell-surface extract could be used as an alternative antimicrobial and antibiofilm agent against foodborne pathogens and spoilage bacteria in food industry.
Topics: Humans; Lacticaseibacillus rhamnosus; Lacticaseibacillus; Xylenes; Anti-Bacterial Agents; Biofilms; Anti-Infective Agents; Bacteria; Plant Extracts
PubMed: 36635630
DOI: 10.1186/s12866-022-02751-3 -
Frontiers in Cellular and Infection... 2022counts as a major endometritis-causing pathogen among dairy cows, which lowered the economic benefits of dairy farming seriously. Probiotic consumption has been...
counts as a major endometritis-causing pathogen among dairy cows, which lowered the economic benefits of dairy farming seriously. Probiotic consumption has been reported to impart beneficial effects on immunomodulation. However, the inflammatory regulation mechanism of probiotics on endometritis in dairy cows remains unexplored. The current work aimed to clarify the mechanism whereby GR-1 ( GR-1) resists bovine endometrial epithelial cells (BEECs) inflammatory injury induced by . The model of cellular inflammatory injury was established in the BEECs, which comes from the uterus of healthy dairy cows using . The outcome of GR-1 addition on inflammation was evaluated in BEECs with -induced endometritis. The underlying mechanisms of anti-inflammation by GR-1 were further explored in -stimulated BEECs. In accordance with the obtained results, the use GR-1 alone could not cause the change of inflammatory factors, while GR-1 could significantly alleviate the expression of -induced inflammatory factors. Based on further study, GR-1 significantly hindered the TLR4 and MyD88 expression stimulated by . Moreover, we observed that in BEECs, GR-1 could inhibit the -elicited expressions of pathway proteins that are associated with NF-κB and MAPKs. Briefly, GR-1 can effectively protect against -induced inflammatory response that may be closely related to the inhibition of TLR4 and MyD88 stimulating NF-κB and MAPKs.
Topics: Animals; Cattle; Cytokines; Epithelial Cells; Escherichia coli; Female; Inflammation; Lacticaseibacillus rhamnosus; NF-kappa B
PubMed: 35310848
DOI: 10.3389/fcimb.2022.809674 -
Frontiers in Bioscience (Landmark... Sep 2023In this study, we analyzed intestinal flora in an experimental mouse model of chronic kidney disease (CKD) and investigated whether oral supplementation with probiotic...
BACKGROUND
In this study, we analyzed intestinal flora in an experimental mouse model of chronic kidney disease (CKD) and investigated whether oral supplementation with probiotic GG could slow the decline in renal function and inflammatory status of mice with CKD.
METHODS
We surgically induced chronic kidney disease in C57BL/6J male mice aged 8-9 weeks. We used dual-stage 5/6 nephrectomy for this, while the mock group underwent a mock procedure. The experimental (CKD mice) and mock group were administered a daily dose of 10 × 109 colony forming unit (CFU) of probiotic GG or 2 g of maltodextrin as a placebo by oral gavage, respectively, for 5 weeks. At the end of the experiment, the fecal samples of the mice were collected and prepared for intestinal microbial diversity analysis. We examined the serum chemistry and renal histology of the mice.
RESULTS
Important serum and blood biomarkers were associated with the development of CKD, including increased serum concentrations of creatine, cystatin C, blood urea nitrogen (BUN), and a protein-interleukin-6 (denoted as IL-6), whereas decreased serum albumin concentration was also observed in the mice with CKD. The intestinal flora of the mice with CKD significantly declined in terms of diversity, richness, and homogeneity. The consumption of GG probiotic via oral gavage significantly decreased the serum concentration level present in creatinine and blood urea nitrogen. However, it increased albumin in the group with CKD. After probiotic treatment, serum IL-6 levels dropped considerably, and the kidney histopathology score in mice with CKD who were given GG improved. Moreover, supplementation with the probiotic significantly improved floral richness and lineage diversity in the mice with CKDConclusions: In this study, we found that probiotics significantly attenuated renal failure development, reduced serum levels of proinflammatory cytokine IL-6, and increased the abundance and lineage diversity of intestinal flora in mice with chronic kidney disease.
Topics: Male; Animals; Mice; Lacticaseibacillus rhamnosus; Interleukin-6; Mice, Inbred C57BL; Kidney; Renal Insufficiency, Chronic; Probiotics; Biomarkers
PubMed: 37796688
DOI: 10.31083/j.fbl2809226 -
Frontiers in Bioscience (Landmark... May 2023is a major component of dental plaque, contributing to cariogenic biofilm formation and inducing dental caries. Attempts have recently been made to use postbiotic...
BACKGROUND
is a major component of dental plaque, contributing to cariogenic biofilm formation and inducing dental caries. Attempts have recently been made to use postbiotic mediators (PMs) to prevent dental caries. This research evaluated the antimicrobial/antibiofilm activity of PMs derived from GG (LGG) and (LR) against .
METHODS
PMs were obtained from the supernatants. The minimum inhibitory concentration, minimum bactericidal concentration, antibiofilm potential, and metabolic activity of PMs against were evaluated using CFU/mL, scanning electron microscopy, and XTT (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) reduction assay. The expression of gene as one of the most important genes involved in biofilm formation was also measured using qRT-PCR.
RESULTS
CFU score was reduced by both PMs, but the reduction was only significant in LGG ( = 0.02). Both PMs caused a significant decrease in the metabolic activity of compared with the controls ( ≤ 0.002). treated with LGG PMs exhibited more destructive effects than LR PMs ( > 0.05). gene expression was significantly downregulated when treated with the PMs obtained from both LGG and LR ( = 0.01 for both).
CONCLUSIONS
We showed that PMs isolated from two strains inhibited biofilm, metabolic activity, and gene expression. Therefore, these derivatives may be a suitable biofilm-destruction agent against . However, the oral environment is a complex ecosystem that needs further investigation.
Topics: Humans; Lacticaseibacillus rhamnosus; Limosilactobacillus reuteri; Streptococcus mutans; Dental Caries; Ecosystem; Lactobacillus; Anti-Infective Agents
PubMed: 37258481
DOI: 10.31083/j.fbl2805088 -
Biomolecules Jan 2021strains dominate the vaginal habitat and they are associated with a lower risk of genital infections. In addition, they contribute to the conservation of the vaginal...
strains dominate the vaginal habitat and they are associated with a lower risk of genital infections. In addition, they contribute to the conservation of the vaginal microbiota by producing postbiotic agents. Previous studies have shown that their predominance involves antimicrobial activity against urogenital pathologies. In this context, probiotics may improve treatment outcomes. The aim of this study was to evaluate the probiotic properties of lactobacilli strains of vaginal origin using a multidisciplinary approach. For this purpose, safety criteria, ability to resist at low pH and bile salts, antimicrobial activity, ability to produce biofilm, capacity to produce hydrogen peroxide and more importantly, auto-aggregation, co-aggregation (with spp.) and adhesion to human cells were evaluated. The strains belonged to the species of , , and Among these, a strain of named AD3 showed the best probiotic properties. As probiotics are already in use in many clinical practice and there are no major safety concerns, AD3 showed promise in becoming a prevention and complementary treatment option for urogenital diseases. Indeed, these results suggest that strain AD3 is non-pathogenic and likely to be safe for human consumption. This study revealed the great amensalistic properties of a new strain which can aim to be used as probiotic in pharmaceutical applications.
Topics: Biofilms; Cell Adhesion; Cell Line, Tumor; Drug Resistance, Microbial; Female; Humans; Hydrogen Peroxide; Lacticaseibacillus rhamnosus; Microbial Sensitivity Tests; Microbial Viability; Probiotics; Vagina
PubMed: 33450875
DOI: 10.3390/biom11010094 -
Nutrients Mar 2022Depression is a common mood disorder that affects around 350 million people worldwide. We studied the effect of supplementation with strains for the treatment of...
CCFM1229 and CCFM1228 Alleviated Depression- and Anxiety-Related Symptoms of Chronic Stress-Induced Depression in Mice by Regulating Xanthine Oxidase Activity in the Brain.
Depression is a common mood disorder that affects around 350 million people worldwide. We studied the effect of supplementation with strains for the treatment of depression. Except for control group ( = 8), C57BL/6J mice were treated with during six weeks of chronic unpredictable stress (depression group: = 9, intervention group: = 7). CCFM1229 and CCFM1228 significantly reduced depressive behaviour in the forced swimming test and tail suspension test, significantly reduced anxiety behaviour in the open field test, and reduced anxiety behaviour in the marble burying test and light/dark box test. CCFM1229 and CCFM1228 significantly increased the brain serotonin and brain-derived neurotrophic factor concentrations, and CCFM1229 significantly decreased the serum corticosterone concentration, all of which are closely associated with the relief of depressive symptoms. Furthermore, CCFM1229 and CCFM1228 were shown to regulate purine metabolism in mice, as indicated by decreases in brain xanthine oxidase activity and an increase in liver adenosine deaminase activity. Anxiety- and depression-related indicators were significantly associated with xanthine oxidase activity in the cerebral cortex. The strains CCFM1229 and CCFM1228 reduced anxiety- and depression-related behaviour in a mouse model of chronic stress-induced depression, which may be achieved by regulating the activity of brain xanthine oxidase.
Topics: Animals; Anxiety; Behavior, Animal; Brain; Depression; Humans; Lacticaseibacillus paracasei; Lacticaseibacillus rhamnosus; Mice; Mice, Inbred C57BL; Xanthine Oxidase
PubMed: 35334950
DOI: 10.3390/nu14061294