Adhesion Of Lactobacilli Research Articles

Development of novel probiotics for the intestinal diseases associated with mucin alterations by adaptive laboratory evolution

Several lactic acid bacterial (LAB) strains have probiotic properties. A crucial requirement for probiotics to benefit the host’s health is their ability to adhere to the intestinal lining enriched with glycosylated mucins. Many intestinal diseases display marked changes in mucin glycosylation such as reduced sialylation and fucosylation. Such alterations have been shown to allow for the lesser adhesion of the probiotic bacteria in vitro. Although probiotics are often used in intestinal diseases, this phenomenon might reduce their in vivo intestinal adhesion, which could be a reason for the ineffectiveness of some probiotics in such conditions as reported in a few studies. Adaptive laboratory evolution (ALE) offers an intuitive way of improving bacterial properties without performing deliberate genetic modifications. In this paper, it is hypothesized that probiotic strains with enhanced adhesion to the mucin altered in intestinal diseases would be better candidates to alleviate the symptoms of these diseases, and such strains can be created through ALE. This hypothesis is supported by a few earlier studies showing the ability of certain other bacteria to mutate themselves to enhance their adhesion to biotic and abiotic environments. The steps involved in testing the hypothesis would be improving the in vitro adhesion of lactobacilli to the intestinal mucus obtained from patients with intestinal diseases by daily adhesion and passaging of the adherent bacteria for several weeks. The improved strains can be subjected to animal studies and human clinical trials in the second part. Since some commensals make short-chain fatty acids from dietary fiber, which stimulate mucin production by the intestinal cells, the clinical trials can be performed under a dietary regime. Apart from providing novel probiotic candidates, such a study can also reveal yet the novel mechanism of adhesion of probiotics to the intestinal environment.

Lactobacilli extracellular vesicles: potential postbiotics to support the vaginal microbiota homeostasis

BackgroundLactobacillus species dominate the vaginal microflora performing a first-line defense against vaginal infections. Extracellular vesicles (EVs) released by lactobacilli are considered mediators of their beneficial effects affecting cellular communication, homeostasis, microbial balance, and host immune system pathways. Up to now, very little is known about the role played by Lactobacillus EVs in the vaginal microenvironment, and mechanisms of action remain poorly understood.ResultsHere, we hypothesized that EVs can mediate lactobacilli beneficial effects to the host by modulating the vaginal microbiota colonization. We recovered and characterized EVs produced by two vaginal strains, namely Lactobacillus crispatus BC5 and Lactobacillus gasseri BC12. EVs were isolated by ultracentrifugation and physically characterized by Nanoparticle Tracking Analysis (NTA) and Dynamic Light Scattering (DLS). EVs protein and nucleic acids (DNA and RNA) content was also evaluated. We explored the role of EVs on bacterial adhesion and colonization, using a cervical cell line (HeLa) as an in vitro model. Specifically, we evaluated the effect of EVs on the adhesion of both vaginal beneficial lactobacilli and opportunistic pathogens (i.e., Escherichia coli, Staphylococcus aureus, Streptococcus agalactiae, and Enterococcus faecalis). We demonstrated that EVs from L. crispatus BC5 and L. gasseri BC12 significantly enhanced the cellular adhesion of all tested lactobacilli, reaching the maximum stimulation effect on strains belonging to L. crispatus species (335% and 269% of average adhesion, respectively). At the same time, EVs reduced the adhesion of all tested pathogens, being EVs from L. gasseri BC12 the most efficient.ConclusionsOur observations suggest for the first time that EVs released by symbiotic Lactobacillus strains favor healthy vaginal homeostasis by supporting the colonization of beneficial species and preventing pathogens attachment. This study reinforces the concept of EVs as valid postbiotics and opens the perspective of developing postbiotics from vaginal strains to maintain microbiota homeostasis and promote women’s health.

Xiong Fu Powder Regulates the Intestinal Microenvironment to Protect Bones Against Destruction in Collagen-Induced Arthritis Rat Models

BackgroundChanges in the intestinal microenvironment affected bone destruction in rheumatoid arthritis (RA), and spleen deficiency (SD) was closely related to the intestinal microenvironment. In this study, we aimed to explore the aggravation of SD on collagen-induced arthritis (CIA) and the bone protection of compound Xiong Fu powder (XFP) on CIA with SD (SD-CIA) based on the intestinal microenvironment.MethodAn SD-CIA rat model was established using Rheum officinale Baill. decoction combined with CIA and then treated with XFP. The aggravating action of SD on CIA rats and the efficacy of XFP were evaluated using AI scores, H&E staining of the joint, and level of serum anti–collagen type II antibody (Col II Ab). Bone destruction was assessed by micro-CT and TRACP staining. In addition, flow cytometry, qRT-PCR, and ELISA were used to evaluate gut mucosal immunity. Moreover, metagenomic sequencing was used to determine the distribution and function of the gut microbiota.ResultsCompared with that in CIA rats, bone destruction in SD-CIA rats was aggravated, as manifested by increased AI scores, more severe joint pathological changes and radiological damage, and increased number of osteoclasts (OCs) in the ankle joint. Meanwhile, the proportion of Tregs/Th17 cells was biased toward Th17 cells in Peyer’s patches. Furthermore, the gene levels of TNF-α, IL-1β, IL-6, and IL-17 were increased. In contrast, the expression of IL-10 and sIgA was decreased in the jejunum and ileum. XFP treatment improved bone damage and intestinal mucosal immune disorders compared with the SD-CIA group. In addition, the distribution and function of the gut microbiota were altered in the SD-CIA group. After XFP treatment, the community and function of the gut microbiota were regulated, manifested as increased abundance of several Lactobacillus species, such as L. acidophilus, which regulates the intestinal Tregs/Th17 cells and quorum sensing pathways, followed by promoting probiotic adhesion to the intestines.ConclusionSD can aggravate bone destruction in CIA rats. Compound XFP may attenuate bone destruction in SD-CIA rats by regulating the intestinal microenvironment. One of the mechanisms is the cross-talk between sIgA secretion regulated by intestinal mucosal Tregs and Th17 cells and adhesion of Lactobacillus mediated by quorum sensing.

How do Lycium barbarum polysaccharides promote the adhesion of Lactobacillus to Caco-2 cells?

Adhesion is thought to increase host-bacterial interactions, thus enabling health benefits to the host. Production of exopolysaccharides increases the chance of probiotic survival in the gastrointestinal tract and promotes adhesion to the epithelium; In our previous research, LBP can be used as potential prebiotics. Therefore we hypothesize that LBP supported the adhesion of Lactobacillus spp. After adding LBP, the result showed that LBP promoted the adhesion of 7 Lactobacillus strains, Lactobacillus acidophilus NCFM had the maximum adhesion rate ranging from 6.2 ± 1.16 to 25.5 ± 1.80 CFU/cell. Specifically, the components of LBP were analyzed by gas chromatography, We found that the similarity of polysaccharide components mainly promoted adhesion. After adding antibiotics, the Lactiplantibacillus plantarum LP-39 was affected; LBP was then added to revert from 5.0 ± 0.63 to 6.5 ± 0.67 CFU/cell. These findings suggest that LBP is potential prebiotics and can enhance the adhesion of Lactobacillus to Caco-2 cells.

Milk fat globule membrane phospholipids modify adhesion of Lactobacillus to mucus-producing Caco-2/Goblet cells by altering the cell envelope

The importance of various Lactobacillus strains and milk components, such as the milk fat globule membrane, has been studied from various perspectives and proven to have a positive role in human health. On one end, lactic acid bacteria produce metabolites with direct effect in the immune system, changes of pH in the gut, and antagonistic substances for pathogenic bacteria as well as competition. On the other end, the milk fat globule membrane improves gastrointestinal status by promoting cell proliferation, epithelial tight junction patterns, and development of intestinal epithelial cells. Interaction between beneficial bacteria and milk fat is a natural occurring phenomenon in dairy products; however, it has not been fully characterized. In this work, we studied the effect of milk phospholipids in the adhesion of Lactobacillus to mucus-producing Caco-2/Goblet cell co-cultures and found that treatment with phospholipids produced bacterial cells with increased surface electronegativity, which was correlated with increased bacterial cells adhered to the intestinal model. Moreover, we utilized an original means of characterizing the adhesion using quartz crystal microbalance. All strains studied, experienced modification of adhesion either physicochemical or kinetic parameters studied. Furthermore, by imaging bacterial cells by electron microscopy, we identified that some strains, such as L. acidophillus and L. casei, metabolized MPL, which improved their adhesion to hydrophilic surfaces such as gold. We identified another group of bacteria, such as L. delbrueckii and L. plantarum, that, instead of metabolizing MPL, kept the phospholipids bound irreversibly to the surface of the cell envelope thus decreasing their adherence to gold surfaces. One of the most important aspects of probiotic lactic acid bacteria —besides survival in the stomach—is the colonization and extended resident time in the intestine to effectively change the gut microbiome. We found that bacterial treatment with milk phospholipids enhances adhesion to intestinal models and will in turn, increase the residence time with the concomitant benefits to the consumer.

Effect of 17\u03b2-estradiol on a human vaginal Lactobacillus crispatus strain

Lactobacilli and estrogens play essential roles in vaginal homeostasis. We investigated the potential direct effect of 17β-estradiol on a vaginal strain of Lactobacillus crispatus, the major bacterial species of the vaginal microbiota. 17β-estradiol (10–6 to 10–10 M) had no effect on L. crispatus growth, but markedly affected the membrane dynamics of this bacterium. This effect appeared consistent with a signal transduction process. The surface polarity and aggregation potential of the bacterium were unaffected by exposure to 17β-estradiol, but its mean size was significantly reduced. 17β-estradiol also promoted biosurfactant production by L. crispatus and adhesion to vaginal VK2/E6E7 cells, but had little effect on bacterial biofilm formation activity. Bioinformatic analysis of L. crispatus identified a membrane lipid raft–associated stomatin/prohibitin/flotillin/HflK domain containing protein as a potential 17β-estradiol binding site. Overall, our results reveal direct effects of 17β-estradiol on L. crispatus. These effects are of potential importance in the physiology of the vaginal environment, through the promotion of lactobacillus adhesion to the mucosa and protection against pathogens.

Evaluation of the Inhibitory Effects of Lactobacillus gasseri and Lactobacillus crispatus on the Adhesion of Seven Common Lower Genital Tract Infection-Causing Pathogens to Vaginal Epithelial Cells.

Background/Purpose: Lactobacillus colonization is important to maintain urogenital flora stability and prevent pathogenic infection. Different Lactobacillus species have distinct properties and effects on the urogenital flora. To select probiotics that colonize the vagina and provide protection against pathogenic infection, we evaluated the adhesion of five Lactobacillus strains and their inhibitory effects on the adhesion of pathogens to vaginal epithelial cells (VECs).Methods and Materials: (1) Lactobacillus adhesion experiments: VK2/E6E7 and primary VECs were used to evaluate the adhesion of two Lactobacillus gasseri and three Lactobacillus crispatus strains. The adhesion of these five Lactobacillus strains was compared. (2) Adhesion inhibition experiments: The inhibitory effects of the five Lactobacillus strains on the adhesion of pathogens (Gardnerella, Mobiluncus, Candida albicans, Streptococcus agalactiae, Staphylococcus aureus, Escherichia coli, and Enterococcus faecalis) were evaluated by adhesion exclusion, displacement, and competition experiments.Results: (1) Lactobacillus adhesion was stronger in the primary VECs than in the VK2/E6E7 VECs (P < 0.05). The adhesion of the three L. crispatus strains was stronger than that of the two L. gasseri strains (P < 0.05). L. crispatus 4# showed the strongest adhesion. (2) The exclusion, displacement, and competition experiments showed that all five Lactobacillus strains significantly inhibited the adhesion of the seven pathogenic strains to the VECs (P < 0.05). The displacement effect was stronger than the exclusion and competition effects of each Lactobacillus strain. (3) The results of the exclusion, displacement, and competition experiments indicated that L. gasseri 1# showed the strongest adhesion inhibition of C. albicans and S. agalactiae. L. crispatus 3# showed the strongest adhesion inhibition of S. aureus, whereas L. crispatus 4# showed the strongest adhesion inhibition of Gardnerella, Mobiluncus, E. coli, and E. faecalis.Conclusion: The source of the VECs might not affect the selection of the most adhesive Lactobacillus strain. L. crispatus showed stronger VEC adhesion than L. gasseri. The degree of antagonism of the Lactobacillus strains toward the different pathogens varied. This result provides incentives for personalized clinical treatment.

Adhesion of Lactobacillus to Intestinal Mucin.

Adhesion to intestinal mucin is one of the main in vitro tests for the study of probiotic strains. Mucins immobilized on microtiter plates and glass slides are easy and excellent methods used for the quantitative analysis of Lactobacillus adhesion. However, to maintain the performance of the quantitative analysis, these methods must be chosen appropriately according to the nature and characteristics of the strain, such as tolerance to surfactant and the ability to self-aggregate. Here we describe two methodologies used to evaluate adhesion of Lactobacillus to mucin, in addition to the isolation and purification of mucins from porcine colonic tissues.

Dietary Nutrients, Proteomes, and Adhesion of Probiotic Lactobacilli to Mucin and Host Epithelial Cells

The key role of diet and environment in human health receives increasing attention. Thus functional foods, probiotics, prebiotics, and synbiotics with beneficial effects on health and ability to prevent diseases are in focus. The efficacy of probiotic bacteria has been connected with their adherence to the host epithelium and residence in the gut. Several in vitro techniques are available for analyzing bacterial interactions with mucin and intestinal cells, simulating adhesion to the host in vivo. Proteomics has monitored and identified proteins of probiotic bacteria showing differential abundance elicited in vitro by exposure to food components, including potential prebiotics (e.g., certain carbohydrates, and plant polyphenols). While adhesion of probiotic bacteria influenced by various environmental factors relevant to the gastrointestinal tract has been measured previously, this was rarely correlated with changes in the bacterial proteome induced by dietary nutrients. The present mini-review deals with effects of selected emerging prebiotics, food components and ingredients on the adhesion of probiotic lactobacilli to mucin and gut epithelial cells and concomitant abundancy changes of specific bacterial proteins. Applying this in vitro synbiotics-like approach enabled identification of moonlighting and other surface-located proteins of Lactobacillus acidophilus NCFM that are possibly associated with the adhesive mechanism.

Lactobacilli survival and adhesion to colonic epithelial cell lines is dependent on long chain fatty acid exposure

Lactobacilli and long chain polyunsaturated fatty acids are commonly consumed as functional foods. However, there is very little research into their interactions. The aim of the present study was to investigate the interaction between fatty acids (FA) and lactobacilli by exploring lactobacilli survival following exposure to different FA and their adhesion to epithelial cells pre‐treated with different FA. Three strains of lactobacilli were cultured with 20 µM eicosapentaenoic acid (EPA, n‐3), docosahexaenoic acid (DHA, n‐3), arachidonic acid (AA, n‐6) or oleic acid (OA, n‐9) to assess survival. Additionally, adhesion of radioactively labelled bacteria to confluent layers of three colorectal cell lines was measured following pre‐treatment of the epithelial cells with 50 µM EPA, DHA, AA. or OA. Results show that exposure to FA slowed log‐phase growth of two human derived strains of lactobacilli, but reduced survival of a chicken derived strain to 20%. Survival was associated with the formation of the FA cyc19:0 in the human derived strains. The chicken derived strain showed greatest adherence to epithelial cells and adhesion was increased following epithelial cell exposure to DHA. In conclusion, the survival and adhesion of lactobacilli in the intestinal tract is likely to be affected by FA content of the diet.Practical applications: The fatty acid composition of the diet has the potential to modulate the behaviour of probiotic bacteria in the gut and in probiotic foods. We showed that combining high polyunsaturated fatty acids (PUFA) with certain probiotics may lead to reduced numbers of probiotic bacteria. Despite this, we showed that PUFA could enhance adhesion of some lactobacilli strains and that increasing the PUFA content of epithelial cells via the diet may aid the adherence of some potentially beneficial lactobacilli. We also highlight a potential concern for the chicken industry whereby PUFA inhibited the growth of the lactobacilli isolated from chicken. With the increasing use of PUFA in chicken feed this could lead to a dysbiosis in normal chicken microflora and requires further investigation.Overview of polyunsaturated fatty acids (PUFA) potential effects on bacteria adhesion. (1) Unabsorbed PUFA directly effects bacteria in the colon. (2) Systemic delivery of PUFA following absorption can (a) Bind peroxisome proliferator‐activated receptors (PPAR), that can lead to production of transforming growth factor‐β resulting in tolerance towards bacteria. (b) Be precursors for series 3 prostaglandins (PG) that lead to lower inflammatory responses. (c) Be precursors to series 2 PG and enhance inflammatory products, however, precursors can bind PPAR and result in inhibition of inflammatory responses. (d) Unsaturated PUFAs lead to a more fluidic membrane composition, potentially altering bacterial adhesion sites.

Effect of apple extracts and selective polyphenols on the adhesion of potential probiotic strains of Lactobacillus gasseri R and Lactobacillus casei FMP

We aimed to investigate the influence of apple extracts (pulp and peel) and their phenolic constituents on the adhesion of two lactobacillus strains to Caco-2 and HT29-MTX intestinal epithelial cells, which were used as models of gastrointestinal tract mucosa. Apple pulp extracts (10 and 20µg/mL) decreased Lactobacillus gasseri R adhesion by 39.7% (P<0.05) and 45.9% (P<0.05), and Lactobacillus casei FMP adhesion by 6.8% and 19.4%, respectively. In contrast, apple peel (10µg/mL) enhanced L. gasseri R adhesion by 35.7% (P<0.05) and L. casei FMP adhesion by 28.2% (P<0.05). Apple peel at 20µg/mL increased the adhesion of both strains.Phenolic profiles of the extracts were characterised using high-resolution and accurate mass quantitative analysis; procyanidin B2 and chlorogenic acid were the main constituents. When tested individually, all the phenolics increased the adhesion of both lactobacilli. Our data indicated that apple peel and its phenolic constituents affected the microbiota-epithelium interaction.

The extracellular proteome of two Bifidobacterium species reveals different adaptation strategies to low iron conditions

BackgroundBifidobacteria are among the first anaerobic bacteria colonizing the gut. Bifidobacteria require iron for growth and their iron-sequestration mechanisms are important for their fitness and possibly inhibit enteropathogens. Here we used combined genomic and proteomic analyses to characterize adaptations to low iron conditions of B. kashiwanohense PV20-2 and B. pseudolongum PV8-2, 2 strains isolated from the feces of iron-deficient African infants and selected for their high iron-sequestering ability.ResultsAnalyses of the genome contents revealed evolutionary adaptation to low iron conditions. A ferric and a ferrous iron operon encoding binding proteins and transporters were found in both strains. Remarkably, the ferric iron operon of B. pseudolongum PV8-2 is not found in other B. pseudolongum strains and likely acquired via horizontal gene transfer. The genome B. kashiwanohense PV20-2 harbors a unique region encoding genes putatively involved in siderophore production.Additionally, the secretomes of the two strains grown under low-iron conditions were analyzed using a combined genomic-proteomic approach. A ferric iron transporter was found in the secretome of B. pseudolongum PV8-2, while ferrous binding proteins were detected in the secretome of B. kashiwanohense PV20-2, suggesting different strategies to take up iron in the strains. In addition, proteins such as elongation factors, a glyceraldehyde-3-phosphate dehydrogenase, and the stress proteins GroEL and DnaK were identified in both secretomes. These proteins have been previously associated with adhesion of lactobacilli to epithelial cells.ConclusionAnalyses of the genome and secretome of B. kashiwanohense PV20-2 and B. pseudolongum PV8-2 revealed different adaptations to low iron conditions and identified extracellular proteins for iron transport. The identified extracellular proteins might be involved in competition for iron in the gastrointestinal tract.

Effects of dietary scFOS and lactobacilli on survival, growth, and disease resistance of hybrid tilapia

The present study was aimed to select gut adhesive Lactobacillus strains and evaluate the combined effects with scFOS on the growth performance, gut adhesive bacteria and disease resistance of juvenile hybrid tilapia. Firstly, the adhesive property of Lactobacillus strains in the gut of tilapia, and effect of scFOS on the adhesion of Lactobacillus were determined by rpoB PCR-DGGE. Fish were fed with diet supplemented with seven probiotic Lactobacillus strains at equal amounts (2.0×107cells/g basal diet) for 2weeks, followed by basal or scFOS supplemented diet for 4weeks. Results showed that strain JCM 1170 and JCM1149 was the most highly-adhesive strains and scFOS increased their relative abundance. In another experiment, fish were fed a diet containing 108cells/g feed of JCM1170 OR JCM1149 with or without scFOS for 5weeks. No significant differences in survival rate, weight gain, or feed conversion were observed in the different treatments. 10 predominant phyla were identified from gut samples by 454 pyrosequencing, and Proteobacteria, Firmicutes, Fusobacteria and Actinobacteria were the most predominant group. The composition of gut adherent microbiota was affected by probiotics/synbiotics. The challenge test showed that synbiotics of JCM 1149 and scFOS protected fish against A. hydrophila (P<0.05). In conclusion, L. plantarum JCM 1149 at 108cell/g feed and scFOS at 1mg/g may be recommended as a synbiotics formulation for tilapia.

Adhesion Properties of Lactic Acid Bacteria on Intestinal Mucin.

Lactic acid bacteria (LAB) are Gram-positive bacteria that are natural inhabitants of the gastrointestinal (GI) tracts of mammals, including humans. Since Mechnikov first proposed that yogurt could prevent intestinal putrefaction and aging, the beneficial effects of LAB have been widely demonstrated. The region between the duodenum and the terminal of the ileum is the primary region colonized by LAB, particularly the Lactobacillus species, and this region is covered by a mucus layer composed mainly of mucin-type glycoproteins. The mucus layer plays a role in protecting the intestinal epithelial cells against damage, but is also considered to be critical for the adhesion of Lactobacillus in the GI tract. Consequently, the adhesion exhibited by lactobacilli on mucin has attracted attention as one of the critical factors contributing to the persistent beneficial effects of Lactobacillus in a constantly changing intestinal environment. Thus, understanding the interactions between Lactobacillus and mucin is crucial for elucidating the survival strategies of LAB in the GI tract. This review highlights the properties of the interactions between Lactobacillus and mucin, while concomitantly considering the structure of the GI tract from a histochemical perspective.

Identification of proteins involved in Lactobacilli adhesion to enterocytes

Identification of proteins involved in Lactobacilli adhesion to enterocytes

MON-PP036: Effect of Selected Polyphenols from Apples on the Adhesion of Lactobacilli

MON-PP036: Effect of Selected Polyphenols from Apples on the Adhesion of Lactobacilli

An assessment of adhesion, aggregation and surface charges of Lactobacillus strains derived from the human oral cavity.

There is limited information concerning the adhesion and aggregation of human oral lactobacilli. In this study, the adhesion of 10 Lactobacillus species was investigated using H357 oral keratinocyte cells as an in vitro model for oral mucosa. Coaggregation with the representative oral pathogen, Streptococcus mutans ATCC 25175, and the physicochemical cell properties was also evaluated. The results demonstrated significant variations in adhesion (42-96%) and aggregation (autoaggregation, 14-95%; coaggregation, 19-65%). All strains showed a high affinity for chloroform, and most strains had a moderate-to-high hydrophobicity. All strains, except Lactobacillus casei and Lactobacillus gasseri, showed a moderate affinity for ethyl acetate. There was a strong association of autoaggregation with coaggregation (rs = 0·883, P < 0·001). The highest mean for autoaggregation (74%) and coaggregation (47%) belonged to the Lact. gasseri strains. Correlations between the adhesion and surface characteristics and aggregation were observed among the Lactobacillus fermentum and Lactobacillus paracasei strains; however, there was a variation in the strains properties within and between species. This study indicated that the Lact. gasseri, Lact. fermentum, and Lact. paracasei strains might be potential probiotics for the human oral cavity given their desirable properties. It should also be emphasized that a selective process for probiotic strains is required. Adhesion to host tissues and bacterial aggregation (auto- and coaggregation) are the highly important criteria for selecting strains with probiotic potential. These abilities are commonly involved with surface-charged characteristics. This is the first study to investigate the oral Lactobacillus species using an oral keratinocyte cell line. Significant results were found for the correlations between the adhesion and surface charge characteristics and for aggregation among certain strains of Lactobacillus gasseri, Lactobacillus fermentum and Lactobacillus paracasei. This observation could be useful when collecting background information for the selection of probiotic strains for use in oral health.

Adhesion of Lactobacilli and their anti-infectivity potential

ABSTRACTThe probiotic potential of lactic acid bacteria primarily point toward colonizing ability of Lactobacilli as the most important attribute for endowing all the known beneficial effects in a host. Lactobacillus species exert health-promoting function in the gastrointestinal tract through various mechanisms such as pathogen exclusion, maintenance of microbial balance, immunomodulation, and other crucial functions. It has been seen that many surface layer proteins are involved in host adhesion, and play significant role in the modification of some signaling pathways within the host cells. Interaction between different bacterial cell surface proteins and host receptor has been imperative for a better understanding of the mechanism through which Lactobacilli exert their health-promoting functions.

Lactobacillus reuteri glyceraldehyde-3-phosphate dehydrogenase functions in adhesion to intestinal epithelial cells.

This study was aimed to identify key surface proteins mediating the adhesion of lactobacilli to intestinal epithelial cells. By using Caco-2 and IPEC-J2 cells labeled with sulfo-NHS-biotin in the western blotting, a protein band of an approximately 37 kDa was detected on the surface layer of Lactobacillus reuteri strains ZJ616, ZJ617, ZJ621, and ZJ623 and Lactobacillus rhamnosus GG. Mass spectrometry analysis using the adhesion-related protein from L. reuteri ZJ617 showed that it was 100% homologous to the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) of L. reuteri JCM 1112 (GenBank: YP_001841377). The ability of L. reuteri ZJ617 to adhere to epithelial cells decreased significantly by treatment with LiCl or by blocking with an anti-GAPDH antibody, in comparison with the untreated strain (p < 0.05). Immunoelectron microscopic and immunofluorescence analyses confirmed that GAPDH is located on the surface layer of L. reuteri ZJ617. The results indicated that the GAPDH protein of L. reuteri ZJ617 acts as an adhesion component that plays an important role in binding to the intestinal epithelial cells.

Surface charge of erythrocytes and lactobacilli S. thermophilus and their intercellular adhesion depend on the concentration of bivalent cations

We propose a simple and accessible model of lactobacilli adhesion to human erythrocytes. The influence of bivalent cations on the surface charge of erythrocytes and lactobacilli Streptococcus thermophilus and their adhesive interaction has been investigated. We have shown that, despite the seemingly similar unidirectional effect of Ca2+ and Mg2+ cations, the cause of decreased adhesion lactobacilli S. thermophilus to human erythrocytes differ. While Ca2+ ions affect the surface charge of erythrocytes, not changing it in S. thermophilus, Mg2+ ions, conversely, affect the surface charge of lactobacilli and do not change it in erythrocytes. Our results confirm our proposition that in this case, the bivalent cations affect the second irreversible stage of adhesion process, but not the physical interactions during the first reversible stage.