Lactobacillus Cell Surface Proteins Involved in Interaction with Mucus and Extracellular Matrix Components

Study of Lactobacillus plantarum coated with Tremella polysaccharides to improve its intestinal adhesion

BACKGROUND

The adhesion of probiotics to the intestine is crucial for their probiotic function. In previous studies, Tremella polysaccharides (TPS) (with sodium casein) have shown the potential to encapsulate probiotics and protect them in a simulated gastrointestinal tract. This study explored the effect of TPS (with sodium casein) on the adhesion of probiotics.

RESULTS

Lactobacillus plantarum was coated with TPS and sodium casein in different proportions, and was freeze-dried. The rheological properties of the mixture of probiotics powder and mucin solution were determined by static and dynamic rheological analysis. Aqueous solutions of probiotic powder and mucin mixture exhibited pseudoplastic fluid rheological properties. The higher the proportion of TPS content, the higher the apparent viscosity and yield stress. The mixed bacterial powder and mucin fluid displayed thixotropy and was in accordance with the Herschel-Bulkley model. The TPS increased the bio-adhesive force of the probiotic powder and mucin. When using TPS as the only carbon source, the adhesion of L. plantarum to Caco-2 cells increased by 228% in comparison with glucose in vitro. Twelve adhesive proteins were also detected in the whole-cell proteome of L. plantarum. Among them, ten adhesive proteins occurred abundantly when grown with TPS as a carbon source.

CONCLUSION

Tremella polysaccharides therefore possess probiotic properties and can promote the intestinal adhesion of L. plantarum. © 2024 Society of Chemical Industry.

In vitro adhesion and anti-inflammatory properties of Limosilactobacillus fermentum FS-10 isolated from infant fecal sample

In this study, seven strains of Limosilactobacillus fermentum were isolated from an infant fecal sample and characterized using in vitro studies. Lactobacillus rhamnosus GG was used as a comparison because it is a well-documented commercial probiotic. The isolates were tested for attributes such as acid and phenol tolerance, bile salt hydrolase (BSH) activity, and antibiotic sensitivity. One isolate, L. fermentum FS-10, displayed enhanced cell surface hydrophobicity (> 85%) and mucin adhesion. Mucin-binding helps colonization in the gut. The immunomodulatory property of L. fermentum FS-10 was evaluated by determining the modulation of pro- and anti-inflammatory factors such as tumor necrosis factor-alpha (TNF-α), interleukin (IL)-10, and nitric oxide (NO) in human acute monocytic leukemia (THP-1) cells under inflammatory conditions induced by lipopolysaccharide (LPS). L. fermentum FS-10 potently downregulated the expression of TNF-α and nitric oxide and upregulated IL-10 levels, indicating an anti-inflammatory response. Safety assessment of the strain revealed the absence of genes for virulence factors, toxin production, and antibiotic resistance, potentiating application as a probiotic strain.

Functional and genomic characterization of a novel probiotic Lactobacillus johnsonii KD1 against shrimp WSSV infection

White Spot syndrome virus (WSSV) causes rapid shrimp mortality and production loss worldwide. This study demonstrates potential use of Lactobacillus johnsonii KD1 as an anti-WSSV agent for post larva shrimp cultivation and explores some potential mechanisms behind the anti-WSSV properties. Treatment of Penaeus vannamei shrimps with L. johnsonii KD1 prior to oral challenge with WSSV-infected tissues showed a significantly reduced mortality. In addition, WSSV copy numbers were not detected and shrimp immune genes were upregulated. Genomic analysis of L. johnsonii KD1 based on Illumina and Nanopore platforms revealed a 1.87 Mb chromosome and one 15.4 Kb plasmid. Only one antimicrobial resistance gene (ermB) in the chromosome was identified. Phylogenetic analysis comparing L. johnsonii KD1 to other L. johnsonii isolates revealed that L. johnsonii KD1 is closely related to L. johnsonii GHZ10a isolated from wild pigs. Interestingly, L. johnsonii KD1 contains isolate-specific genes such as genes involved in a type I restriction-modification system and CAZymes belonging to the GT8 family. Furthermore, genes coding for probiotic survival and potential antimicrobial/anti-viral metabolites such as a homolog of the bacteriocin helveticin-J were found. Protein-protein docking modelling suggests the helveticin-J homolog may be able to block VP28-PmRab7 interactions and interrupt WSSV infection.

Can proteins, protein hydrolysates and peptides cooperate with probiotics to inhibit pathogens?

Studies have shown that probiotics can effectively inhibit pathogens in the presence of proteins, protein hydrolysates and peptides (protein derivates). However, it is still unclear the modes of probiotics to inhibit pathogens regulated by protein derivates. Therefore, we summarized the possible effects of protein derivates from different sources on probiotics and pathogens. There is abundant evidence that proteins and peptides from different sources can significantly promote the proliferation of probiotics and increase their secretion of antibacterial substances. Such proteins and peptides can also stimulate the adhesion of probiotics to intestinal epithelial cells and contribute to regulating intestinal immunity, but they seem to have the negative effects on pathogens. Moreover, a direct effect of proteins on intestinal cells is summarized. Whether or not they can cooperate with probiotics to inhibit pathogens using above possible mechanisms were discussed. Furthermore, there seems to be no consistent conclusions that protein derivates have synergistic effects with probiotics, and there is still limited evidence on the inhibiting patterns. Therefore, the existing problems and shortcomings are noted, and future research direction is proposed.

The Enolase of the Haemophilus influenzae Mediates Binding to Collagens: An Extracellular Matrix Component

Enolase proteins play a significant role as moonlighting proteins. In their role as surface-associated enolase, they have multiple functions as they interact with extracellular matrix proteins. Type I and III collagens are the major constituents of this extracellular matrix, and collagen is one of the targets of interaction with the enolase of many pathogens, thereby helping the colonization process and promoting the subsequent invasion of the host. This work aimed to determine the participation of non-typeable H. influenzae enolase as a collagen-binding protein. In this study, through the use of in vitro tests it was demonstrated that recombinant enolase of non-typeable H. influenzae (rNTHiENO) strongly binds to type I collagen. Using molecular docking, the residues that could take part in the interaction of non-typeable H. influenzae enolase-type I collagen (NTHiENO-Cln I) and non-typeable H. influenzae enolase-type III collagen (NTHiENO-Cln III) were identified. However, in vitro assays show that NTHiENO has a better affinity to interact with Cln I, concerning type Cln III. The interaction of NTHiENO with collagen could play a significant role in the colonization process; this would allow H. influenzae to increase its virulence factors and strengthen its pathogenesis.

Ligilactobacillus salivarius 7247 Strain: Probiotic Properties and Anti-Salmonella Effect with Prebiotics

The Ligilactobacillus salivarius 7247 (LS7247) strain, originally isolated from a healthy woman's intestines and reproductive system, has been studied for its probiotic potential, particularly against Salmonella Enteritidis (SE) and Salmonella Typhimurium (ST) as well as its potential use in synbiotics. LS7247 showed high tolerance to gastric and intestinal stress and effectively adhered to human and animal enterocyte monolayers, essential for realizing its probiotic properties. LS7247 showed high anti-Salmonella activity. Additionally, the cell-free culture supernatant (CFS) of LS7247 exhibited anti-Salmonella activity, with a partial reduction upon neutralization with NaOH (p < 0.05), suggesting the presence of anti-Salmonella factors such as lactic acid (LA) and bacteriocins. LS7247 produced a high concentration of LA, reaching 124.0 ± 2.5 mM after 48 h of cultivation. Unique gene clusters in the genome of LS7247 contribute to the production of Enterolysin A and metalloendopeptidase. Notably, LS7247 carries a plasmid with a gene cluster identical to human intestinal strain L. salivarius UCC118, responsible for class IIb bacteriocin synthesis, and a gene cluster identical to porcine strain L. salivarius P1ACE3, responsible for nisin S synthesis. Co-cultivation of LS7247 with SE and ST pathogens reduced their viability by 1.0-1.5 log, attributed to cell wall damage and ATP leakage caused by the CFS. For the first time, the CFS of LS7247 has been shown to inhibit adhesion of SE and ST to human and animal enterocytes (p < 0.01). The combination of Actigen prebiotic and the CFS of LS7247 demonstrated a significant combined effect in inhibiting the adhesion of SE and ST to human and animal enterocytes (p < 0.001). These findings highlight the potential of using the LS7247 as a preventive strategy and employing probiotics and synbiotics to combat the prevalence of salmonellosis in animals and humans caused by multidrug resistant (MDR) strains of SE and ST pathogens.

Mucosa-Mimetic Materials for the Study of Intestinal Homeostasis and Disease

Mucus is a viscoelastic hydrogel that lines and protects the epithelial surfaces of the body that houses commensal microbiota and functions in host defense against pathogen invasion. As a first-line physical and biochemical barrier, intestinal mucus is involved in immune surveillance and spatial organization of the microbiome, while dysfunction of the gut mucus barrier is implicated in several diseases. Mucus can be collected from a variety of mammalian sources for study, however, established methods are challenging in terms of scale and efficiency, as well as with regard to rheological similarity to native human mucus. Therefore, there is a need for mucus-mimetic hydrogels that more accurately reflect the physical and chemical profile of the in vivo human epithelial environment to enable the investigation of the role of mucus in human disease and interactions with the intestinal microbiome. This review will evaluate the material properties of synthetic mucus mimics to date designed to address the above need, with a focus toward an improved understanding of the biochemical and immunological functions of these biopolymers related to utility for research and therapeutic applications.

Metagenomics and metagenome-assembled genomes mining of health benefits in jalebi batter, a naturally fermented cereal-based food of India

Jalebi is one of the oldest Indian traditional fermented wheat-based confectioneries. Since jalebi is prepared by natural fermentation, diverse microbial community is expected to play bio-functional activities. Due to limited studies, information on microbial community structure in jalebi is unknown. Hence, the present study is aimed to profile the microbial community in jalebi by shotgun metagenomics and also to predict putative probiotic and functional genes by metagenome-assembled genome (MAG). Bacteria were the most abundant domain (91.91%) under which Bacillota was the most abundant phylum (82%). The most abundant species was Lapidilactobacillus dextrinicus followed by several species of lactic acid bacteria, acetic acid bacteria including few yeasts. Lap. dextrinicus was also significantly abundant in jalebi when compared to similar fermented wheat-based sourdough. Additionally, Lap. bayanensis, Pediococcus stilesii, and yeast- Candida glabrata, Gluconobacter japonicus, Pichia kudriavzevii, Wickerhamomyces anomalus were only detected in jalebi, which are not detected in sourdough. Few viruses and archaea were detected with < 1 % abundance. In silico screening of genes from the abundant species was mined using both KEGG and EggNOG database for putative health beneficial attributes. Circular genomes of five high-quality MAGs, identified as Lapidilactobacillus dextrinicus, Enterococcus hirae, Pediococcus stilesii, Acetobacter indonesiensis and Acetobacter cibinongensis, were constructed separately and putative genes were mapped and annotated. The CRISPR/Cas gene clusters in the genomes of four MAGs except Acetobacter cibinongensis were detected. MAGs also showed several secondary metabolites. Since, the identified MAGs have different putative genes for bio-functional properties, this may pave the way to selectively culture the uncultivated putative microbes for jalebi production. We believe this is the first report on metagenomic and MAGs of jalebi.

Vaginal colonization of women after oral administration of Lactobacillus crispatus strain NTCVAG04 from the human microbiota

BACKGROUND

The genomic approach has deeply changed the microbiology perspective, mainly concerning the microbioma identification. In this regard, some microbes colonize the healthy vagina. Vaginitis is a common gynecological ailment and includes bacterial vaginosis (BV), usually caused by local dysbiosis, such as a microbiota imbalance. Lactobacilli are the most prevalent bacteria colonizing the healthy vagina, so guaranteeing local eubiosis. In particular, vaginal colonization by L. crispatus is associated with low susceptibility to BV. Therefore, probiotics, such as life bacteria providing health advantages, are a current strategy in the prevention or treatment of vaginitis, including BV. However, there is a low level of evidence that probiotics after ingestion could really colonize the vagina. In particular, no study evidenced that L. crispatus after ingestion can colonize vagina. Therefore, the current study explored the capacity of Biovaginil® (NTC, Milan, Italy) dietary supplement containing Lactobacillus crispatus NTCVAG04 and vitamin A to colonize the gut and vagina in women with a history of vaginitis/vaginosis.

METHODS

Twenty fertile females (mean age 34.0 years) were enrolled in the study. Rectal and vaginal swabs were collected at baseline and after the first and second cycle of Biovaginil®. Each cycle lasted 14 days within two consecutive menstrual periods.

RESULTS

Seven women were excluded from the analysis because the samples were technically not evaluable. One woman dropped out because of mild adverse event. At the end of the study, nine women (75%) had positive rectal swab for L. crispatus NTCVAG04, and 8 of them also had positive vaginal swab.

CONCLUSIONS

The current study provided the first evidence that L. crispatus NTCVAG04, administered by two Biovaginil® courses, colonized both the gut and vagina. Moreover, the L. crispatus NTCVAG04 strain could be considered the archetype of a new class of oral probiotics that actively colonize the vagina, and that could be called "colpobiotics."

Screening of Lactiplantibacillus plantarum 67 with Strong Adhesion to Caco-2 Cells and the Effects of Protective Agents on Its Adhesion Ability during Vacuum Freeze Drying

Adhesion to the intestinal tract provides the foundation for Lactobacillus to exert its benefits. Vacuum freeze-drying (VFD) is currently one of the main processing methods for Lactobacillus products. Therefore, the effects of VFD on the adhesion and survival of Lactiplantibacillus plantarum 67 were investigated in this study. The results show that L. plantarum 67 exhibits remarkable tolerance following successive exposure to simulated saliva, gastric juice and intestinal juice, and also has a strong adhesion ability to Caco-2 cells. The adhesion and survival rates of L. plantarum 67 significantly decreased after VFD in phosphate-buffered saline (PBS), whereas they significantly increased in protective agents (PAs) (p < 0.05). Scanning electron microscope observations show that L. plantarum 67 aggregated more to Caco-2 cells in PAs than in PBS, and its shape and size were protected. Proteomics detection findings indicated that differentially expressed proteins (DEPs) related to adhesins and vitality and their pathways in L. plantarum 67 were significantly affected by VFD (p < 0.05). However, the expression of DEPs (such as cold shock protein, cell surface protein, adherence protein, chitin-binding domain and extracellular transglycosylase, membrane-bound protein) was improved by PAs. Compared with PBS, the PAs significantly adjusted the phosphotransferase system and amino sugar and nucleotide sugar metabolism pathways (p < 0.05). VFD decreased the adhesion and vitality of L. plantarum 67, while the PAs could exert protective effects by regulating proteins and pathways related to adhesion and vitality.

The panda-derived Lactiplantibacillus plantarum BSG201683 improves LPS-induced intestinal inflammation and epithelial barrier disruption in vitro

Captive pandas are suffering from intestinal infection due to intestinal microbiota characterized by a high abundance of Enterobacteriaceae induced by long-term captivity. Probiotic supplements showed improvement in intestinal barrier function and inflammation. However, the effects of panda-derived probiotics on the intestinal epithelium and inflammation have not been elucidated. In the present study, lipopolysaccharide (LPS) impaired Caco-2 and RAW264.7 inflammatory models were applied to assess the protection of Lactiplantibacillus plantarum BSG201683 (L. plantarum G83) on barrier disruption and inflammation. The results showed that treatment with L. plantarum G83 significantly decreased the paracellular permeability to fluorescein isothiocyanate conjugated dextran (MW 4000, FITC-D4) after LPS induction. Meanwhile, L. plantarum G83 alleviated the reduction in tight junction (TJ) proteins and downregulated proinflammatory cytokines caused by LPS in Caco-2 cells. L. plantarum G83 also significantly decreased the expression and secretion of pro-inflammatory cytokines in LPS-induced RAW264.7 cells. In addition, the IL-10 increased in both Caco-2 and RAW264.7 cells after L. plantarum G83 treatment. The phagocytosis activity of RAW264.7 cells was significantly increased after L. plantarum G83 treatment. Toll-like receptor 4/ nuclear factor kappa-B (TLR4/NF-κB) signaling pathways were significantly down-regulated after L. plantarum G83 intervention, and the phosphorylation of NF-κB/p65 was consistent with this result. Our findings suggest that L. plantarum G83 improves intestinal inflammation and epithelial barrier disruption in vitro.

The regulation of simulated artificial oro-gastrointestinal transit stress on the adhesion of Lactobacillus plantarum S7

BACKGROUND

Oro-gastrointestinal stress in the digestive tract is the main stress to which orally administered probiotics are exposed. The regulation of oro-gastrointestinal transit (OGT) stress on the adhesion and survival of probiotics under continuous exposure to simulated salivary-gastric juice-intestinal juice was researched in this study.

RESULTS

Lactobacillus plantarum S7 had a higher survival rate after exposure to simulated OGT1 (containing 0.15% bile salt) stress and OGT2 (containing 0.30% bile salt) stress. The adhesion ability of L. plantarum S7 was significantly increased by OGT1 stress (P < 0.05) but was not changed significantly by OGT2 stress (P > 0.05), and this trend was also observed in terms of the thickness of the surface material of L. plantarum S7 cells. The expression of surface proteins of L. plantarum S7, such as the 30 S ribosomal proteins, mucus-binding protein and S-layer protein, was significantly downregulated by OGT stress (P < 0.05); meanwhile, the expression of moonlight proteins, such as glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphoglycorate kinase (PGK), beta-phosphoglucomutase (PGM1), GroEL and glucose-6-phosphate isomerase (PGI), was significantly upregulated (P < 0.05). However, the upregulation of GAPDH, PGK, PGM1 and PGI mediated by OGT1 stress was greater than those mediated by OGT2 stress. The quorum sensing pathway of L. plantarum S7 was changed significantly by OGT stress compared with no OGT stress cells (P < 0.05), and the expression of Luxs in the pathway was significantly upregulated by OGT1 stress (P < 0.05). The ABC transportation pathway was significantly altered by OGT1 stress (P < 0.05), of which the expression of the peptide ABC transporter substrate-binding protein and energy-coupling factor transporter ATP-binding protein EcfA was significantly upregulated by OGT stress (P < 0.05). The glycolide metabolism pathway was significantly altered by OGT1 stress compared with that in response to OGT2 stress (P < 0.05).

CONCLUSION

L. plantarum S7 had a strong ability to resist OGT stress, which was regulated by the proteins and pathways related to OGT stress. The adhesion ability of L. plantarum S7 was enhanced after continuous exposure to OGT1 stress, making it a potential probiotic with a promising future for application.

Novel Starter Strain Enterococcus faecium DMEA09 from Traditional Korean Fermented Meju

The Enterococcus faecium strain DMEA09 was previously isolated from traditional Korean fermented meju. The objective of the current study was to investigate the traits of E. faecium strain DMEA09 as a starter candidate, focusing on its safety and technological properties. Regarding its safety, the DMEA09 strain was found to be sensitive to nine antibiotics (ampicillin, chloramphenicol, erythromycin, gentamicin, kanamycin, streptomycin, tetracycline, tylosin, and vancomycin) by showing lower minimum inhibitory concentrations (MICs) than the cut-off values suggested by the European Union Food Safety Authority for these nine antibiotics. However, its MIC value for clindamycin was twice as high as the cut-off value. A genomic analysis revealed that strain DMEA09 did not encode the acquired antibiotic resistance genes, including those for clindamycin. The DMEA09 strain did not show hemolysis as a result of analyzing α- and β-hemolysis. It did not form biofilm either. A genomic analysis revealed that strain DMEA09 did not encode for any virulence factors including hemolysin. Most importantly, multilocus sequence typing revealed that the clonal group of strain DMEA09 was distinguished from clinical isolates. Regarding its technological properties, strain DMEA09 could grow in the presence of 6% salt. It showed protease activity when the salt concentration was 3%. It did not exhibit lipase activity. Its genome possessed 37 putative protease genes and salt-tolerance genes for survivability under salt conditions. Consequently, strain DMEA09 shows safe and technological properties as a new starter candidate. This was confirmed by genome analysis.

Metagenome-assembled genomes for biomarkers of bio-functionalities in Laal dahi, an Indian ethnic fermented milk product

Laal dahi is a sweetened and soft pudding-like fermented milk product of the Eastern regions of India, which has not been studied for its microbial community structures and health promoting functionality in terms of 'omics' approaches. We applied metagenomic and metagenomes-assembled genomes (MAGs) tools to decipher the biomarkers for genes encoding for different health promoting functionalities in laal dahi. Abundance of bacterial domains was observed with negligible presence of eukaryotes and viruses. Bacillota was the most abundant phylum with different bacterial species viz., Enterococcus italicus, Lactococcus raffinolactis, Lactobacillus helveticus, Bifidobacterium mongoliense, Hafnia alvei, Lactococcus lactis, Acetobacter okinawensis, Streptococcus thermophilus, Thermus thermophilus, Leuconostoc citreum, Leuconostoc pseudomesenteroides, Acetobacter orientalis, Lactobacillus gallinarum, Lactococcus chungangensis and Lactobacillus delbrueckii. Comparison of laal dahi microbiome with that of similar fermented milk products was also carried out after retrieving the metagenomic datasets from public databases. Significant abundance of Lb. helveticus, E. italicus, Lc. raffinolactis and Lc. lactis in laal dahi. Interestingly, Bifidobacterium mongoliense, Lb. gallinarum, Lc. chungangensis and Acetobacter okinawensis were only detected in laal dahi but Streptococcus infantarius, Lacticaseibacillus rhamnosus and Lb. johnsonii were absent. Reconstruction of putative single environment-specific genomes from metagenomes in addition to subsampling of the abundant species resulted in five high-quality MAGs identified as Lactobacillus delbrueckii, Lactobacillus helveticus, Lactococcus chungangensis, Lactococcus lactis and Streptococcus thermophilus. All MAGs showed the presence of various genes with several putative functions corresponding to different probiotic and prebiotic functions, short-chain fatty acids production, immunomodulation, antitumor genes, essential amino acid and vitamin biosynthesis. Genes for γ-Aminobutyric acid (GABA) production were only detected in MAG of Lactococcus lactis. Gene clusters for secondary metabolites (antimicrobial peptides) were detected in all MAGs except Lc. chungangensis. Additionally, detection of clustered regularly interspaced short palindromic repeats (CRISPR)-associated (Cas) elements was observed only in Lactobacillus delbrueckii and Streptococcus thermophilus. Annotation of several genes with potential health beneficial properties in all five MAGs may support the need to explore the culturability of these MAGs for future use in controlled fermentation of functional dairy products.

Gluconic acid improves performance of newly weaned piglets associated with alterations in gut microbiome and fermentation

BACKGROUND

Weaning is a critical phase in the pigs' life and gut health might be compromised. Gluconic acid was shown to be poorly absorbed but readily fermented to butyrate in the gut which in turn can improve gut function. Hence, a total of 144 weaning pigs were fed the experimental diets for 42 days. Three treatments were replicated in 8 pens with 6 piglets each: control; low dietary dose of gluconic acid, 9 g/kg; and high dietary dose of gluconic acid, 18 g/kg. After 21 days, one piglet from each pen was sampled for blood haematology and biochemistry, fore- and hindgut digesta characteristics and microbiota, and distal small intestinal histo-morphological indices and gene expression.

RESULTS

Feeding gluconic acid enhanced performance in period d 0-14 post-weaning, in particular feed intake was increased (P = 0.028), though the high dose did not show benefits over the low dose. Regarding d 0-42, feed intake was elevated (P = 0.026). At d 21, piglets fed 18 g/kg gluconic acid showed a trend for lower number of total white blood cells (P = 0.060), caused by particularly lower numbers of lymphocytes as compared to control (P = 0.028). Highly reduced plasma urea was found for groups fed gluconic acid, it amounted to 2.6 and 2.6 mmol/L for the 9 and 18 g/kg level, respectively, as compared to 3.8 mmol/L in control (P = 0.003). Feeding gluconic acid promoted the relative abundance of lactic-acid-producing and acid-utilizing bacteria. In distal small intestine, Lactobacillus amylovorus increased substantially from 11.3 to 82.6% for control and gluconic acid 18 g/kg, respectively (P < 0.05). In mid-colon, the butyrate producers Faecalibacterium prausnitzii (P > 0.05) and Megasphaera elsdenii (P < 0.05) showed highest abundance in gluconic acid 18 g/kg. Consequently, in caecum and mid-colon, increased relative molar percentage of butyrate were found, e.g., 10.0, 12.9 et 14.7% in caecum for gluconic acid at 0, 9, and 18 g/kg, respectively (P = 0.046). Elevated mRNA anti-inflammatory cytokine and survival signalling levels in distal small intestinal mucosa were found by feeding gluconic acid which might be mediated by butyrate.

CONCLUSIONS

Gluconic acid may have potential to alleviate the postweaning growth-check in pigs by altering microbiota composition and fermentation in the gut.

A symbiotic physical niche in Drosophila melanogaster regulates stable association of a multi-species gut microbiota

The gut is continuously invaded by diverse bacteria from the diet and the environment, yet microbiome composition is relatively stable over time for host species ranging from mammals to insects, suggesting host-specific factors may selectively maintain key species of bacteria. To investigate host specificity, we used gnotobiotic Drosophila, microbial pulse-chase protocols, and microscopy to investigate the stability of different strains of bacteria in the fly gut. We show that a host-constructed physical niche in the foregut selectively binds bacteria with strain-level specificity, stabilizing their colonization. Primary colonizers saturate the niche and exclude secondary colonizers of the same strain, but initial colonization by Lactobacillus species physically remodels the niche through production of a glycan-rich secretion to favor secondary colonization by unrelated commensals in the Acetobacter genus. Our results provide a mechanistic framework for understanding the establishment and stability of a multi-species intestinal microbiome.

The probiotic and immunomodulation effects of Limosilactobacillus reuteri RGW1 isolated from calf feces

Introduction

Limosilactobacillus reuteri is a gut symbiont with multiple remarkable beneficial effects on host health, and members of L. reuteri are valuable probiotic agents. However, L. reuteri showed obvious host specificity.

Methods

In our study, a novel L. reuteri RGW1 was isolated from feces of healthy calves, and its potential as a probiotic candidate were assessed, by combining in vitro, in vivo experiments and genomic analysis.

Results and discussion

RGW1 was sensitive to all the antibiotics tested, and it did not contain any virulence factor-coding genes. This isolate showed good tolerance to acid (pH 3.0), 0.3% bile salt, and simulated gastric fluid. Moreover, this isolate showed a high hydrophobicity index (73.7 ± 4.6%) and was able to adhere to Caco-2 cells, and antagonize Escherichia coli F5. Treatment of LPS-induced mice with RGW1 elevated TGF-β and IL-10 levels, while RGW1 cell-free supernatant (RCS) decreased TNF-α levels in the sera. Both RGW1 and RCS increased the villus height and villus height/crypt depth ratio of colon. Genomic analysis revealed the mechanism of the probiotic properties described above, and identified the capacity of RGW1 to biosynthesize L-lysine, folate, cobalamin and reuterin de novo. Our study demonstrated the novel bovine origin L. reuteri RGW1 had multiple probiotic characteristics and immunomodulation effects, and provided a deeper understanding of the relationship between these probiotic properties and genetic features.

Treatment of Dyslipidemia through Targeted Therapy of Gut Microbiota

Dyslipidemia is a multifaceted condition with various genetic and environmental factors contributing to its pathogenesis. Further, this condition represents an important risk factor for its related sequalae including cardiovascular diseases (CVD) such as coronary artery disease (CAD) and stroke. Emerging evidence has shown that gut microbiota and their metabolites can worsen or protect against the development of dyslipidemia. Although there are currently numerous treatment modalities available including lifestyle modification and pharmacologic interventions, there has been promising research on dyslipidemia that involves the benefits of modulating gut microbiota in treating alterations in lipid metabolism. In this review, we examine the relationship between gut microbiota and dyslipidemia, the impact of gut microbiota metabolites on the development of dyslipidemia, and the current research on dietary interventions, prebiotics, probiotics, synbiotics and microbiota transplant as therapeutic modalities in prevention of cardiovascular disease. Overall, understanding the mechanisms by which gut microbiota and their metabolites affect dyslipidemia progression will help develop more precise therapeutic targets to optimize lipid metabolism.

Cell-surface protein YwfG of Lactococcus lactis binds to α-1,2-linked mannose

Lactococcus lactis strains are used as starter cultures in the production of fermented dairy and vegetable foods, but the species also occurs in other niches such as plant material. Lactococcus lactis subsp. lactis G50 (G50) is a plant-derived strain and potential candidate probiotics. Western blotting of cell-wall proteins using antibodies generated against whole G50 cells detected a 120-kDa protein. MALDI-TOF MS analysis identified it as YwfG, a Leu-Pro-any-Thr-Gly cell-wall-anchor-domain-containing protein. Based on a predicted domain structure, a recombinant YwfG variant covering the N-terminal half (aa 28-511) of YwfG (YwfG28-511) was crystallized and the crystal structure was determined. The structure consisted of an L-type lectin domain, a mucin-binding protein domain, and a mucus-binding protein repeat. Recombinant YwfG variants containing combinations of these domains (YwfG28-270, YwfG28-336, YwfG28-511, MubR4) were prepared and their interactions with monosaccharides were examined by isothermal titration calorimetry; the only interaction observed was between YwfG28-270, which contained the L-type lectin domain, and d-mannose. Among four mannobioses, α-1,2-mannobiose had the highest affinity for YwfG28-270 (dissociation constant = 34 μM). YwfG28-270 also interacted with yeast mannoproteins and yeast mannan. Soaking of the crystals of YwfG28-511 with mannose or α-1,2-mannobiose revealed that both sugars bound to the L-type lectin domain in a similar manner, although the presence of the mucin-binding protein domain and the mucus-binding protein repeat within the recombinant protein inhibited the interaction between the L-type lectin domain and mannose residues. Three of the YwfG variants (except MubR4) induced aggregation of yeast cells. Strain G50 also induced aggregation of yeast cells, which was abolished by deletion of ywfG from G50, suggesting that surface YwfG contributes to the interaction with yeast cells. These findings provide new structural and functional insights into the interaction between L. lactis and its ecological niche via binding of the cell-surface protein YwfG with mannose.

L. rhamnosus CNCM I-3690 survival, adaptation, and small bowel microbiome impact in human

Fermented foods and beverages are a significant source of dietary bacteria that enter the gastrointestinal (GI) tract. However, little is known about how these microbes survive and adapt to the small intestinal environment. Colony-forming units (CFU) enumeration and viability qPCR of Lacticaseibacillus rhamnosus CNCM I-3690 in the ileal effluent of 10 ileostomy subjects during 12-h post consumption of a dairy product fermented with this strain demonstrated the high level of survival of this strain during human small intestine passage. Metatranscriptome analyses revealed the in situ transcriptome of L. rhamnosus in the small intestine, which was contrasted with transcriptome data obtained from in vitro cultivation. These comparative analyses revealed substantial metabolic adaptations of L. rhamnosus during small intestine transit, including adjustments of carbohydrate metabolism, surface-protein expression, and translation machinery. The prominent presence of L. rhamnosus in the effluent samples did not elicit an appreciable effect on the composition of the endogenous small intestine microbiome, but significantly altered the ecosystem's overall activity profile, particularly of pathways associated with carbohydrate metabolism. Strikingly, two of the previously recognized gut-brain metabolic modules expressed in situ by L. rhamnosus (inositol degradation and glutamate synthesis II) are among the most dominantly enriched activities in the ecosystem's activity profile. This study establishes the survival capacity of L. rhamnosus in the human small intestine and highlights its functional adjustment in situ, which we postulate to play a role in the probiotic effects associated with this strain.

Extracellular membrane vesicles from Limosilactobacillus reuteri strengthen the intestinal epithelial integrity, modulate cytokine responses and antagonize activation of TRPV1

Bacterial extracellular membrane vesicles (MV) are potent mediators of microbe-host signals, and they are not only important in host-pathogen interactions but also for the interactions between mutualistic bacteria and their hosts. Studies of MV derived from probiotics could enhance the understanding of these universal signal entities, and here we have studied MV derived from Limosilactobacillus reuteri DSM 17938 and BG-R46. The production of MV increased with cultivation time and after oxygen stress. Mass spectrometry-based proteomics analyses revealed that the MV carried a large number of bacterial cell surface proteins, several predicted to be involved in host-bacteria interactions. A 5'-nucleotidase, which catalyze the conversion of AMP into the signal molecule adenosine, was one of these and analysis of enzymatic activity showed that L. reuteri BG-R46 derived MV exhibited the highest activity. We also detected the TLR2 activator lipoteichoic acid on the MV. In models for host interactions, we first observed that L. reuteri MV were internalized by Caco-2/HT29-MTX epithelial cells, and in a dose-dependent manner decreased the leakage caused by enterotoxigenic Escherichia coli by up to 65%. Furthermore, the MV upregulated IL-1β and IL-6 from peripheral blood mononuclear cells (PBMC), but also dampened IFN-γ and TNF-α responses in PBMC challenged with Staphylococcus aureus. Finally, we showed that MV from the L. reuteri strains have an antagonistic effect on the pain receptor transient receptor potential vanilloid 1 in a model with primary dorsal root ganglion cells from rats. In summary, we have shown that these mobile nanometer scale MV reproduce several biological effects of L. reuteri cells and that the production parameters and selection of strain have an impact on the activity of the MV. This could potentially provide key information for development of innovative and more efficient probiotic products.

Lactobacillus johnsonii enhances the gut barrier integrity via the interaction between GAPDH and the mouse tight junction protein JAM-2

Commensal intestinal microbiota interacts with gut epithelial cells in the host by binding to specific host receptors. Several pattern recognition receptors on the gut that sense conserved microbial-associated molecular patterns have been reported; however, many of the gut receptor molecules involved in bacterial binding have not yet been identified. In this study, commensal intestinal bacteria interacting with mouse gut surface proteins were screened from fecal bacterial samples, to identify novel receptors on the epithelial cells in the mouse gut. Among the screened intestinal lactic acid bacteria, the frequently isolated Lactobacillus johnsonii MG was used for the purification of gut receptor proteins. An approximately 30 kDa protein was purified using affinity resin coupled surface layer proteins isolated from L. johnsonii MG. The purified gut protein was identified as a member of the tight junction protein family, junctional adhesion molecule-2 (JAM-2). As expected, the tight junctions of Caco-2 cells damaged by H₂O₂ were repaired by incubation with L. johnsonii MG. RNA sequence analysis showed significant upregulation of the expression of genes for tight junctions, anti-inflammatory effects, transcriptional regulation, and apoptosis in Caco-2 cells, following L. johnsonii MG treatment. In L. johnsonii MG, the surface layer 40 kDa protein was purified with gut protein-coupled affinity resin and identified as the moonlighting protein glyceraldehyde-3-phosphate dehydrogenase (GAPDH). These results suggest that L. johnsonii MG promotes the barrier function integrity in Caco-2 cells via GAPDH-JAM-2 binding. Here, we propose a promising approach to identify novel gut receptor molecules based on commensal bacterial interactions and understand host-bacterial communication in a mouse model.

Lactobacilli and human dental caries: more than mechanical retention

Lactobacilli have been considered as major contributors to human dental caries for over a century. Recent in vitro model studies have shown that when compared to Streptococcus mutans, a keystone pathogen of human dental caries, the ability of lactobacilli to form biofilms is poor, although differences exist between the different major species. Further studies using molecular and bioinformatics approaches provide evidence that multiple mechanisms, including adhesin-receptor mediated physical contact with S. mutans, facilitate the adherence and establishment of lactobacilli on the tooth surface. There is also evidence that under conditions like continuous sugar consumption, weak acids and other antimicrobials such as bacteriocins from lactobacilli can become detrimental to the microbial community, especially those in the proximity. Details on the underlying mechanisms of how different Lactobacillus sp. establish and persist in the highly complex microbiota on the tooth surface await further investigation.

Health-Promoting Nature of Lactococcus lactis IBB109 and Lactococcus lactis IBB417 Strains Exhibiting Proliferation Inhibition and Stimulation of Interleukin-18 Expression in Colorectal Cancer Cells

Lactic acid bacteria (LAB) are Gram-positive bacteria which are considered for use as adjuvant therapeutics in management of various disease ailments, including obesity, irritable bowel syndrome, lactose intolerance and cancer. To investigate the possible use of Lactococcus lactis strains from our collection in treatment of gastrointestinal cancer, we tested them for the ability to arrest proliferation of human colorectal adenocarcinoma cells (Caco-2). Results of the BrdU assay showed that the anti-proliferative activity of L. lactis cells is strain-specific. We found that particularly, two strains, L. lactis IBB109 and L. lactis IBB417, exhibited the most potent inhibitory effect. Moreover, both strains triggered interleukin 18 gene expression, normally inhibited in Caco-2 (cancer) cells. To examine the probiotic potential of the two strains, we tested them for bile salts and acid tolerance, as well as adhesion properties. Both isolates exhibited probiotic potential—they survived in the presence of 0.3% bile salts and tolerated exposure to low pH and osmotic stress. Notably, we found that L. lactis IBB417 displayed better adherence to mucus and Caco-2 cells than L. lactis IBB109. Additionally, by microdilution tests we confirmed that both strains are sensitive to all nine antibiotics of human and veterinary importance listed by the European Food Safety Authority. Finally, by in silico investigations of whole genome sequencing data, we revealed the genetic features of L. lactis IBB109 and L. lactis IBB417 that can be associated with functional (e.g., adhesion and carbohydrate metabolic genes) and safety (e.g., virulence and antibiotic resistance) aspects of the strains, confirming their health-promoting potential.

Mucus, commensals, and the immune system

The immune system in the large intestine is separated from commensal microbes and comparatively rare enteric pathogens by a monolayer of diverse epithelial cells overlaid with a compact and adherent inner mucus layer and a looser outer mucus layer. Microorganisms, collectively referred to as the mucus-associated (MA) microbiota, physically inhabit this mucus barrier, resulting in a dynamic and incessant dialog to maintain both spatial segregation and immune tolerance. Recent major findings reveal novel features of the crosstalk between the immune system and mucus-associated bacteria in health and disease, as well as disease-related peripheral immune signatures indicative of host responses to these organisms. In this brief review, we integrate these novel observations into our overall understanding of host-microbiota mutualism at the colonic mucosal border and speculate on the significance of this emerging knowledge for our understanding of the prevention, development, and progression of chronic intestinal inflammation.

Effects of probiotic supplementation on abdominal pain severity in pediatric patients with irritable bowel syndrome: a systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Probiotic supplementation has been used to alleviate abdominal pain in children and adolescents with irritable bowel syndrome (IBS), but the evidence is not compelling. Thus, a systematic review and meta-analysis of randomized clinical trials (RCTs) were performed to investigate the effects of probiotic supplementation on abdominal pain in pediatric patients with IBS.

METHODS

PubMed/MEDLINE, Web of Science, Scopus, Cochrane Library, and Embase were the available databases searched to find relevant randomized clinical trials up to April 2021. The effect size was expressed as weighted mean difference (WMD) and 95% confidence interval (CI).

RESULTS

Seven RCTs with 441 participants were included, from which the meta-analysis demonstrated that probiotic supplementation has a significant effect on reducing abdominal pain in pediatric patients with IBS (WMD = - 2.36; 95% CI - 4.12 to - 0.60; P = 0.009). Although our study involved children and adolescents (≤ 18 years), the effects of probiotic supplementation seem to be more potent in patients under 10 years old (WMD = - 2.55; 95% CI - 2.84 to - 2.27) compared to patients aged 10-18 years (WMD = - 1.70; 95% CI - 2.18 to - 1.22). The length of supplementation longer than four weeks was more effective (WMD = - 2.43; 95% CI - 2.76 to - 2.09).

CONCLUSION

Probiotic supplementation can reduce abdominal pain in pediatric patients with IBS.

Molecular genetics for probiotic engineering: dissecting lactic acid bacteria

The composition of the gut microbiome is greatly influenced by nutrition and dietary alterations which can also induce large temporary microbial shifts. However, the molecular mechanisms that promote these changes remain to be determined. Species of the family Lactobacillaceae and Bacillus species are genetically manipulatable bacteria that are naturally found in the human gastrointestinal (GI) tract and are often considered models of beneficial microbiota. Here, we identify specific conserved molecular pathways that play a key role in host colonization by beneficial members of the microbiota. In particular, we highlight three pathways important to the success of lactic acid bacteria (LAB) in the GI tract: glycolysis and fermentation, microbial communication via membrane vesicles, and condition-dependent antibiotic production. We elaborate on how the understanding of these circuits can lead to the development of novel therapeutic approaches to combat GI tract infections.

Lactobacillus crispatus DSM25988 as novel bioactive agent to co-aggregate Streptococcus pyogenes and to exclude it by binding to human cells

Streptococcus pyogenes, a group A streptococcus, is the major bacterial pathogen responsible for acute bacterial infection of the human oropharynx and the causative agent of scarlet fever. Estimates of the global burden of S. pyogenes related diseases revealed 616 million cases of pharyngitis, and at least 517,000 deaths due to severe invasive diseases and sequelae. Here we describe Lactobacillus crispatus DSM25988 that was identified among hundreds of Lactobacillus strains (referring to all organisms that were classified as Lactobacillaceae until 2020) showing ability to prevent adhesion of S. pyogenes to Detroit 562 cells, and to exhibit a masking and co-aggregating effect on S. pyogenes in vitro. L. crispatus DSM25988 also inhibits invasion of cultured human epithelial pharyngeal cells by S. pyogenes. Competitive binding to fibronectin might be involved in the inhibition process. Antiviral activity of the L. crispatus DSM25988 cells were identified in an in vitro cell model demonstrating that L. crispatus effectively excludes viruses from epithelial cells using SARS-CoV2 proteins as a model. This finding points to the potential of DSM25988 to protect cells from virus infection. Biological activity is retained in heat treated cells. The heat-treated Lactobacillus strain was further developed into functional throat lozenges, wherein its biological activity is stably maintained in the formulation. Lozenges containing L. crispatus DSM25988 underwent testing in an uncontrolled, prospective user study in 44 subjects with symptoms of sore throat for a period of up to 14 days. The study data shows promising safety and efficacy of the medical device when used against symptoms of sore throat like scratchy feeling, hoarse voice and swallowing pain.

Isolation, characterization and comparative genomics of potentially probiotic Lactiplantibacillus plantarum strains from Indian foods

Lactiplantibacillus plantarum is one of the most diverse species of lactic acid bacteria found in various habitats. The aim of this work was to perform preliminary phenotypic and genomic characterization of two novel and potentially probiotic L. plantarum strains isolated from Indian foods, viz., dhokla batter and jaggery. Both the strains were bile and acid tolerant, utilized various sugars, adhered to intestinal epithelial cells, produced exopolysaccharides and folate, were susceptible for tetracycline, erythromycin, and chloramphenicol, did not cause hemolysis, and exhibited antimicrobial and plant phenolics metabolizing activities. The genetic determinants of bile tolerance, cell-adhesion, bacteriocins production, riboflavin and folate biosynthesis, plant polyphenols utilization, and exopolysaccharide production were found in both the strains. One of the strains contained a large number of unique genes while the other had a simultaneous presence of glucansucrase and fructansucrase genes which is a rare trait in L. plantarum. Comparative genome analysis of 149 L. plantarum strains highlighted high variation in the cell-adhesion and sugar metabolism genes while the genomic regions for some other properties were relatively conserved. This work highlights the unique properties of our strains along with the probiotic and technically important genomic features of a large number of L. plantarum strains.

Characterization of a novel fructosyltransferase InuCA from Lactobacillus crispatus that attaches to the cell surface by electrostatic interaction

Fructosyltransferases (FTases), a group of carbohydrate-active enzymes, synthesize fructooligosaccharides (FOS) and fructans, which are promising prebiotics for human health. Here we originally identified a novel FTase InuCA from L. crispatus, a dominant species in the vaginal microbiotas of human. InuCA was characterized by a shortest C-terminus and the highest isoelectric point among the reported Lactobacillus FTases. InuCA was an inulosucrase and produced a serial of FOS using sucrose as substrate at a moderate temperature. Surprisingly, the C-terminal deletion mutant synthesized oligosaccharides with fructosyl chain longer than that of the wild type, suggesting that the C-terminal part blocked the binding of long-chain receptor. Moreover, InuCA bound to the cell surface by electrostatic interaction, which was dependent on the environmental pH and represented a distinctive binding mode in FTases. The catalytic and structural properties of InuCA will be contributed to the FTases engineering and the knowledge of the adaptation of L. crispatus in the vaginal environment. Importance L. crispatus is one of the most important species in human vaginal microbiotas and its persistence is strongly negatively correlated with the vaginal diseases. Our research reveals that a novel inulosucrase InuCA is present in L. cirspatus. InuCA keeps the ability to synthesize prebiotic fructo-oligosaccharides, although it lacks a large part of the C-terminal region compared to other FTases. Remarkably, the short C-terminus of InuCA blocks the transfructosylation activity for producing oligosaccharides with longer chain, which is meaningful to the directional modification of FTases and the oligosaccharide products. Besides the catalytic activity, InuCA is anchored on the cell surface dependent on the environmental pH and may be also involved in the adhesion of L. crispatus to the vaginal epithelial cells. Since L. crispatus plays an essential role in the normal vaginal micro-ecosystem, the described work will be helpful to elucidate the functional genes and colonization mechanism of the dominant species.

Intestinal mucus barrier: a missing piece of the puzzle in food allergy

The prevalence of food allergies has reached epidemic levels but the cause remains largely unknown. We discuss the clinical relevance of the gut mucosal barrier as a site for allergic sensitization to food. In this context, we focus on an important but overlooked part of the mucosal barrier in pathogenesis, the glycoprotein-rich mucus layer, and call attention to both beneficial and detrimental aspects of mucus-gut microbiome interactions. Studying the intricate links between the mucus barrier, the associated bacteria, and the mucosal immune system may advance our understanding of the mechanisms and inform prevention and treatment strategies in food allergy.

The prospect of orally administered monoclonal secretory IgA (SIgA) antibodies to prevent enteric bacterial infections

Eliminating diarrheal diseases as a leading cause of childhood morbidity and mortality in low- and middle-income countries (LMICs) will require multiple intervention strategies. In this review, we spotlight a series of preclinical studies investigating the potential of orally administered monoclonal secretory IgA (SIgA) antibodies (MAbs) to reduce disease associated with three enteric bacterial pathogens: Campylobacter jejuni, enterotoxigenic Escherichia coli (ETEC), and invasive Salmonella enterica serovar Typhimurium. IgA MAbs targeting bacterial surface antigens (flagella, adhesins, and lipopolysaccharide) were generated from mice, humanized mice, and human tonsillar B cells. Recombinant SIgA1 and/or SIgA2 derivates of those MAbs were purified from supernatants following transient transfection of 293 cells with plasmids encoding antibody heavy and light chains, J-chain, and secretory component (SC). When administered to mice by gavage immediately prior to (or admixed with) the bacterial challenge, SIgA MAbs reduced infection C. jejuni, ETEC, and S. Typhimurium infections. Fv-matched IgG1 MAbs by comparison were largely ineffective against C. jejuni and S. Typhimurium under the same conditions, although they were partially effective against ETEC. While these findings highlight future applications of orally administered SIgA, the studies also underscored the fundamental challenges associated with using MAbs as prophylactic tools against enteric bacterial diseases.

Supplemental magnolol or honokiol attenuates adverse effects in broilers infected with Salmonella pullorum by modulating mucosal gene expression and the gut microbiota

Background

Salmonella pullorum is one of the most harmful pathogens to avian species. Magnolol and honokiol, natural compounds extracted from Magnolia officinalis, exerts anti-inflammatory, anti-oxidant and antibacterial activities. This study was conducted to evaluate the effects of dietary supplemental magnolol and honokiol in broilers infected with S. pullorum. A total of 360 one-day-old broilers were selected and randomly divided into four groups with six replicates: the negative control group (CTL), S. pullorum-infected group (SP), and the S. pullorum-infected group supplemented with 300 mg/kg honokiol (SPH) or magnolol (SPM).

Results

The results showed that challenging with S. pullorum impaired growth performance in broilers, as indicated by the observed decreases in body weight (P < 0.05) and average daily gains (P < 0.05), along with increased spleen (P < 0.01) and bursa of Fabricus weights (P < 0.05), serum globulin contents, and the decreased intestine villus height and villus/crypt ratios (P < 0.05). Notably, supplemental magnolol and honokiol attenuated these adverse changes, and the effects of magnolol were better than those of honokiol. Therefore, we performed RNA-Seq in ileum tissues and 16S rRNA gene sequencing of ileum bacteria. Our analysis revealed that magnolol increased the α-diversity (observed species, Chao1, ACE, and PD whole tree) and β-diversity of the ileum bacteria (P < 0.05). In addition, magnolol supplementation increased the abundance of Lactobacillus (P < 0.01) and decreased unidentified Cyanobacteria (P < 0.05) both at d 14 and d 21. Further study confirmed that differentially expressed genes induced by magnolol and honokiol supplementation enriched in cytokine-cytokine receptor interactions, in the intestinal immune network for IgA production, and in the cell adhesion molecule pathways.

Conclusions

Supplemental magnolol and honokiol alleviated S. pullorum-induced impairments in growth performance, and the effect of magnolol was better than that of honokiol, which could be partially due to magnolol’s ability to improve the intestinal microbial and mucosal barrier.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-021-00611-0.

Mutual Preservation: A Review of Interactions Between Cervicovaginal Mucus and Microbiota

At mucosal surfaces throughout the body mucus and mucins regulate interactions between epithelia and both commensal and pathogenic bacteria. Although the microbes in the female genital tract have been linked to multiple reproductive health outcomes, the role of cervicovaginal mucus in regulating genital tract microbes is largely unexplored. Mucus-microbe interactions could support the predominance of specific bacterial species and, conversely, commensal bacteria can influence mucus properties and its influence on reproductive health. Herein, we discuss the current evidence for both synergistic and antagonistic interactions between cervicovaginal mucus and the female genital tract microbiome, and how an improved understanding of these relationships could significantly improve women’s health.