Purification and antimicrobial mechanism of a novel bacteriocin produced by Lactobacillus rhamnosus 1.0320

Antibacterial Activity, Probiotic Potential, and Biocontrol Efficacy of Two Lactic Acid Bacteria Against Penicillium expansum on Fresh Grapes

Lactic acid bacteria are commonly present in various sources and possess significant probiotic properties. They can inhibit pathogenic bacteria and fungi simultaneously, making them promising candidates as bio-preservatives. This study investigated two potential probiotic strains: Lactiplantibacillus plantarum LR5-2 (isolated from fermented meat products) and Lacticaseibacillus rhamnosus SQ63 (isolated from infant feces). The study evaluated their aggregation ability, anti-pathogenic activity, safety, and tolerance to gastrointestinal conditions, phenol, and bile salts. Additionally, their biological control potential against Penicillium expansum on fresh grapes was assessed. The results demonstrated that both strains exhibited high survival rates under extreme gastrointestinal conditions, enhanced Auto-aggregation, co-aggregation, and hydrophobicity. They displayed strong antioxidant activity and significant antibacterial effects against 11 pathogenic fungi and foodborne pathogens. Biosafety testing revealed that both strains are sensitive to most antibiotics, do not produce biogenic amines, and exhibit no hemolytic or DNase activity. In grapes, L. plantarum LR5-2 and L. rhamnosus SQ63 significantly reduced the incidence and disease index of P. expansum infection. In conclusion, the characterization analysis and bio-preservation experiments revealed that LR5-2 and SQ63 have strong potential as probiotics and bio-preservatives.

Current challenges and development strategies of bacteriocins produced by lactic acid bacteria applied in the food industry

Given the great importance of natural biopreservatives in the modern food industry, lactic acid bacteria (LAB)-producing bacteriocins have gained considerable attention due to their antimicrobial activity against foodborne pathogens and spoilage bacteria. Although numerous LAB-producing bacteriocins have demonstrated efficiency in preserving food quality in various applications, only a limited number of these compounds have been commercially approved to date. The currently unclear gastrointestinal metabolism of bacteriocins may pose safety risks, as well as cytotoxicity and immunogenicity, which need to be seriously considered before their application. A more noteworthy concern lies in whether bacteriocins induce an imbalance in the gut microbiota, thereby leading to alterations in the abundance of health-associated microorganisms and their metabolites in the gastrointestinal tract. Accordingly, this review presents unique insights into the challenges arising from metabolic interactions between LAB-producing bacteriocins and the gastrointestinal tract. Besides, the application of bacteriocins in the food industry faces challenges arising from the low production yield, weak stability, and insufficient antimicrobial activity. The corresponding development strategies are proposed for conducting the systematic and comprehensive evaluation of the potential safety risks of bacteriocins and their metabolites. The strategies also focus on the rational design to increase the activity and stability, the fermentation control to enhance the production yield, and the hurdle and embedding technology to improve the application effects. It definitively discloses the perspective of bacteriocins to become natural, sustainable, safe, and eco-friendly biological preservatives for the advancement of the food industry.

Improved Antibacterial Properties of Fermented and Enzymatically Hydrolyzed Bee Pollen and Its Combined Effect with Antibiotics

Background/Objectives: A variety of phytochemicals from different plants are collected by bees into bee pollen granules. This research focused on evaluating the effects of lactic acid fermentation and enzymatic hydrolysis on the antibacterial activity of bee pollen and its interaction with antibiotics. There is limited knowledge regarding the interactions between treated bee pollen extracts and antibiotics, and this study contributes to the field by providing new insights into the antibacterial activity of pollen subjected to eight distinct treatment methods. Methods: Bee pollen's bacterial fermentation using a Lacticaseibacillus rhamnosus culture and spontaneous fermentation were performed. Bee pollen hydrolysis was performed using commercial enzymes, including enzyme mixtures as well as pure enzymes. The agar well diffusion assay was employed to assess the antibacterial activity against Staphylococcus aureus, Listeria monocytogenes, and Salmonella enterica serovars Enteritidis and Typhimurium, as well as their interaction with antibiotics (ceftazidime, ciprofloxacin, oxytetracycline dihydrate, and erythromycin). Results: This study showed an enhancement in bee pollen's antibacterial activity after both fermentation and enzymatic hydrolysis. The increase varied with the pollen's origin, treatment type, and culture used for antimicrobial tests. More than 77% of bee pollen extracts demonstrated a synergistic effect with antibiotics across all tested bacterial strains, while antagonistic interactions were comparatively rare. Conclusions: The applied treatment methods can improve the antibacterial properties of bee pollen. Bee pollen extracts, in combination with antibiotics, can enhance their effectiveness. These findings provide new insights into the potential use of bee pollen in combating bacterial infections.

Antibacterial mechanism of CO2 combined with low temperature against Shewanella putrefaciens by biochemical and metabolomics analysis

To further reveal the inhibition mechanism of carbon dioxide (CO2) on Shewanella putrefaciens (S. putrefaciens), influence on metabolic function was studied by biochemical and metabolomics analysis. Accordingly, reduction of intracellular pH (pHi), depolarization of cell membrane and accumulation of reactive oxygen species (ROS) indicated that CO2 changed the membrane permeability of S. putrefaciens. Besides, adenosine triphosphate (ATP), ATPase, nicotinamide adenine dinucleotide (NAD+/NADH) and ratios of NADH/NAD+ were detected, indicating a role of CO2 in repressing respiratory pathway and electron transport. According to metabolomics results, CO2 induced differential expressions of metabolites, disordered respiratory chain and weakened energy metabolism of S. putrefaciens. Inhibition of respiratory rate-limiting enzymes also revealed that electron transfer of respiratory chain was blocked, cell respiration was weakened, and thus energy supply was insufficient under CO2 stress. These results revealed that CO2 caused disruption of metabolic function, which might be the main cause of growth inhibition for S. putrefaciens.

Design of probiotic delivery systems and their therapeutic effects on targeted tissues

The microbiota at different sites in the body is closely related to disease. The intake of probiotics is an effective strategy to alleviate diseases and be adjuvant in their treatment. However, probiotics may suffer from harsh environments and colonization resistance, making it difficult to maintain a sufficient number of live probiotics to reach the target sites and exert their original probiotic effects. Encapsulation of probiotics is an effective strategy. Therefore, probiotic delivery systems, as effective methods, have been continuously developed and innovated to ensure that probiotics are effectively delivered to the targeted site. In this review, initially, the design of probiotic delivery systems is reviewed from four aspects: probiotic characteristics, processing technologies, cell-derived wall materials, and interactions between wall materials. Subsequently, the review focuses on the effects of probiotic delivery systems that target four main microbial colonization sites: the oral cavity, skin, intestine, and vagina, as well as disease sites such as tumors. Finally, this review also discusses the safety concerns of probiotic delivery systems in the treatment of disease and the challenges and limitations of implementing this method in clinical studies. It is necessary to conduct more clinical studies to evaluate the effectiveness of different probiotic delivery systems in the treatment of diseases.

Enhancement of exercise-induced fatigue alleviation and liver selenium regulation through in situ nanoselenium synthesis by Lactobacillus rhamnosus cells, empowered by Ganoderma lucidum spore loading

Given the increasing awareness of the negative effects of fatigue on daily activities, mental health, and quality of life, antifatigue supplements are becoming increasingly popular among consumers. Selenium has been found to have antifatigue potential in high dosage, but may cause toxicity effects to the body. In this study, inorganic selenium was first converted to nanoselenium particles via in situ synthesis by Lactobacillus rhamnosus SHA113 (Se-LRS), and then loaded by Ganoderma lucidum spores (GLS). The resulting products were not only assessed for their antioxidant activities, but also the antifatigue potential in mice. As a result, both Se-LRS and the Se-LRS/GLS complex exhibited higher antioxidant and antibacterial activities in simulated gastrointestinal fluids compared to isolated selenium nanoparticles. The Se-LRS/GLS complex demonstrated sustained release of selenium in simulated gastrointestinal fluids and showed significant alleviation of exercise-induced fatigue indicators, but relatively lower liver selenium accumulation in the mice, surpassing the effects of isolated nanoselenium. No toxicity was found to Caco-2 cells for Se-LRS/GLS complex at 2 µg/mL. This is a novel approach to enhance the antifatigue potential of selenium without causing extra toxicity.

A Review on Bacteriocin Extraction Techniques from Lactic Acid Bacteria

Lactic acid bacteria (LAB) are widely known for the production of secondary metabolites such as organic acids and other bioactive compounds such as bacteriocins. Finding a broad application in food and healthcare, bacteriocins have received increased attention due to their inherent antimicrobial properties. However, the extraction of bacteriocins is often plagued with low yields due to the complexity of the extraction processes and the diversity of bacteriocins themselves. Here, we review the current knowledge related to bacteriocin extraction on the different extraction techniques for isolating bacteriocins from LAB. The advantages and disadvantages of each technique will also be critically appraised, taking into account factors such as extraction efficiency, scalability and cost-effectiveness. This review aims to guide researchers and professionals in selecting the most suitable approach for bacteriocin extraction from LAB by illuminating the respective advantages and limitations of various extraction techniques.

Unveiling a New Antimicrobial Peptide with Efficacy against P. aeruginosa and K. pneumoniae from Mangrove-Derived Paenibacillus thiaminolyticus NNS5-6 and Genomic Analysis

This study focused on the discovery of the antimicrobial peptide (AMP) derived from mangrove bacteria. The most promising isolate, NNS5-6, showed the closest taxonomic relation to Paenibacillus thiaminolyticus, with the highest similarity of 74.9%. The AMP produced by Paenibacillus thiaminolyticus NNS5-6 exhibited antibacterial activity against various Gram-negative pathogens, especially Pseudomonas aeruginosa and Klebsiella pneumoniae. The peptide sequence consisted of 13 amino acids and was elucidated as Val-Lys-Gly-Asp-Gly-Gly-Pro-Gly-Thr-Val-Tyr-Thr-Met. The AMP mainly exhibited random coil and antiparallel beta-sheet structures. The stability study indicated that this AMP was tolerant of various conditions, including proteolytic enzymes, pH (1.2-14), surfactants, and temperatures up to 40 °C for 12 h. The AMP demonstrated 4 µg/mL of MIC and 4-8 µg/mL of MBC against both pathogens. Time-kill kinetics showed that the AMP acted in a time- and concentration-dependent manner. A cell permeability assay and scanning electron microscopy revealed that the AMP exerted the mode of action by disrupting bacterial membranes. Additionally, nineteen biosynthetic gene clusters of secondary metabolites were identified in the genome. NNS5-6 was susceptible to various commonly used antibiotics supporting the primary safety requirement. The findings of this research could pave the way for new therapeutic approaches in combating antibiotic-resistant pathogens.

A Novel Bacitracin-like Peptide from Mangrove-Isolated Bacillus paralicheniformis NNS4-3 against MRSA and Its Genomic Insights

The global rise of antimicrobial resistance (AMR) presents a critical challenge necessitating the discovery of novel antimicrobial agents. Mangrove microbes are valuable sources of new antimicrobial compounds. This study reports the discovery of a potent antimicrobial peptide (AMP) from Bacillus paralicheniformis NNS4-3, isolated from mangrove sediment, exhibiting significant activity against methicillin-resistant Staphylococcus aureus (MRSA). The AMP demonstrated a minimum inhibitory concentration ranging from 1 to 16 µg/mL in the tested bacteria and exhibited bactericidal effects at higher concentrations. Structural analysis revealed a bacitracin-like configuration and the peptide acted by disrupting bacterial membranes in a time- and concentration-dependent manner. The AMP maintained stability under heat, proteolytic enzymes, surfactants, and varying pH treatments. The ten biosynthetic gene clusters (BGCs) of secondary metabolites were found in the genome. Detailed sequence comparison of the predicted bacitracin BGC indicated distinct DNA sequences compared to previously reported strains. Although the antibiotic resistance genes were found, this strain was susceptible to antibiotics. Our findings demonstrated the potential of Bacillus paralicheniformis NNS4-3 and its AMP as a promising agent in combating AMR. The genetic information could be pivotal for future applications in the healthcare industry, emphasizing the need for continued exploration of marine microbial diversity in drug discovery.

Classification and Multi-Functional Use of Bacteriocins in Health, Biotechnology, and Food Industry

Bacteriocins is the name given to products of the secondary metabolism of many bacterial genera that must display antimicrobial activity. Although there are several bacteriocins described today, it has not been possible to reach a consensus on the method of classification for these biomolecules. In addition, many of them are not yet authorized for therapeutic use against multi-drug-resistant microorganisms due to possible toxic effects. However, recent research has achieved considerable progress in the understanding, classification, and elucidation of their mechanisms of action against microorganisms, which are of medical and biotechnological interest. Therefore, in more current times, protocols are already being conducted for their optimal use, in the hopes of solving multiple health and food conservation problems. This review aims to synthetize the information available nowadays regarding bacteriocins, and their classification, while also providing an insight into the future possibilities of their usage for both the pharmaceutical, food, and biotechnological industry.

The role of fermentation with lactic acid bacteria in quality and health effects of plant-based dairy analogues

The modern food industry is undergoing a rapid change with the trend of production of plant-based food products that are more sustainable and have less impact on nature. Plant-based dairy analogues have been increasingly popular due to their suitability for individuals with milk protein allergy or lactose intolerance and those preferring a plant-based diet. Nevertheless, plant-based products still have insufficient nutritional quality, undesirable structure, and earthy, green, and bean-like flavor compared to dairy products. In addition, most plant-based foods contain lesser amounts of essential nutrients, antinutrients limiting the bioavailability of some nutrients, and allergenic proteins. Novel processing technologies can be applied to have a homogeneous and stable structure. On the other hand, fermentation of plant-based matrix with lactic acid bacteria can provide a solution to most of these problems. Additional nutrients can be produced and antinutrients can be degraded by bacterial metabolism, thereby increasing nutritional value. Allergenic proteins can be hydrolyzed reducing their immunoreactivity. In addition, fermentation has been found to reduce undesired flavors and to enhance various bioactivities of plant foods. However, the main challenge in the production of fermented plant-based dairy analogues is to mimic familiar dairy-like flavors by producing the major flavor compounds other than organic acids, yielding a flavor profile similar to those of fermented dairy products. Further studies are required for the improvement of the flavor of fermented plant-based dairy analogues through the selection of special microbial cultures and formulations.

A Response Surface Methodological Approach for Large-Scale Production of Antibacterials from Lactiplantibacillus plantarum with Potential Utility against Foodborne and Orthopedic Infections

A variety of bacteria, including beneficial probiotic lactobacilli, produce antibacterials to kill competing bacteria. Lactobacilli secrete antimicrobial peptides (AMPs) called bacteriocins and organic acids. In the food industry, bacteriocins, but even whole cell-free supernatants, are becoming more and more important as bio-preservatives, while, in orthopedics, bacteriocins are introducing new perspectives in biomaterials technologies for anti-infective surfaces. Studies are focusing on Lactiplantibacillus plantarum (previously known as Lactobacillus plantarum). L. plantarum exhibits great phenotypic versatility, which enhances the chances for its industrial exploitation. Importantly, more than other lactobacilli, it relies on AMPs for its antibacterial activity. In this study, Response Surface Methodology (RSM) through a Box-Behnken experimental design was used to estimate the optimal conditions for the production of antibacterials by L. plantarum. A temperature of 35 °C, pH 6.5, and an incubation time of 48 h provided the highest concentration of antibacterials. The initial pH was the main factor influencing the production of antibacterials, at 95% confidence level. Thanks to RSM, the titer of antibacterials increased more than 10-fold, this result being markedly higher than those obtained in the very few studies that have so far used similar statistical methodologies. The Box-Behnken design turned out to be a valid model to satisfactorily plan a large-scale production of antibacterials from L. plantarum.

Oxidized/unmodified-polyethylene microplastics neurotoxicity in mice: Perspective from microbiota-gut-brain axis

Microplastics (MPs) are inevitably oxidized in the environment, and their potential toxicity to organisms has attracted wide attention. However, the neurotoxicity and mechanism of oxidized polyethylene (Ox-PE) MPs to organisms remain unclear. Herein, we prepared oxidized low-density polyethylene (Ox-LDPE) and established a model of MPs exposure by continuously orally gavage of C57BL/6 J mice with LDPE-MPs/Ox-LDPE-MPs for 28 days with or without oral administration of Lactobacillus plantarum DP189 and galactooligosaccharides (DP189&GOS). The experimental results indicated that LDPE-MPs or Ox-LDPE-MPs caused several adverse effects in mice, mainly manifested by behavioral changes, disruption of the intestinal and blood-brain barrier (BBB), and simultaneous oxidative stress, inflammatory reactions, and pathological damage in the brain and intestines. Brain transcriptomic analysis revealed that the cholinergic synaptic signaling pathways, which affect cognitive function, were significantly disrupted after exposure to LDPE-MPs or Ox-LDPE-MPs. Real-time quantitative polymerase chain reaction and Western Blotting results further demonstrated that the critical genes (Slc5a7, Chat and Slc18a3) and proteins (Chat and Slc18a3) in the cholinergic synaptic signaling pathway were significantly down-regulated after exposure to LDPE-MPs or Ox-LDPE-MPs. These alterations lead to reduced acetylcholine concentration, which causes cognitive dysfunction in mice. Importantly, the DP189&GOS interventions effectively mitigated the MPs-induced cognitive dysfunction and intestinal microbiota alteration, improved intestinal and BBB integrity, attenuated the oxidative stress and inflammatory response, and also saw a rebound in the release of acetylcholine. These results indicated that LDPE-MPs and Ox-LDPE-MPs exert neurotoxic effects on mice by inducing oxidative stress, inflammatory responses, and dysregulation of cholinergic signaling pathways in the mouse brain. That probiotic supplementation is effective in attenuating MPs-induced neurotoxicity in mice. Overall, this study reveals the potential mechanisms of neurotoxicity of LDPE-MPs and Ox-LDPE-MPs on mice and their improvement measures, necessary to assess the potential risks of plastic contaminants to human health.

Fermented Mare Milk and Its Microorganisms for Human Consumption and Health

Mare milk is consumed by approximatively 30 million people in the world. In countries in Asia and East Europe, mare milk is mainly consumed as source of fermented products, called koumiss, airag or chigee, alcoholic beverages obtained by means of a culture of bacteria and lactose-fermenting yeasts. Recent research concerning mare milk and its derivatives deals mainly with their potential employment for human health. Studies about the isolation and characterization of Lactobacillus spp. and yeasts from koumiss have been aimed at assessing the potential functional properties of these micro-organisms and to find their employment for the industrial processing of mare milk. The aim of this literature review is to summarize recent research about microorganisms in fermented mare milk products and their potential functional properties.

Purification and characterization of a novel low-molecular-weight antimicrobial peptide produced by Lactiplantibacillus plantarum NMGL2

The present study aimed to purify and characterize a novel low-molecular-weight antimicrobial peptide (AMP) named as PNMGL2 produced by Lactiplantibacillus plantarum NMGL2. The AMP was effectively separated and purified by ethyl acetate extraction and DEAE-Sepharose anion exchange chromatography. Tricine-SDS-PAGE of the purified AMP showed a major protein band below 1.7 kDa, which was identified by MALDI-TOF MS to be a hexapeptide LNFLKK (761.95 Da), and structurally characterized to be combination of helixes and random coil by a PEP-FOLD 3 De novo approach. The antimicrobial activity of LNFLKK was confirmed by chemical synthesis of the peptide that showed clear inhibition (MIC 7.8 mg/mL) against both Gram-positive bacteria (Staphylococcus aureus and Listeria monocytogenes), and Gram-negative bacteria (Enterobacter sakazakii, Escherichia coli and Shigella flexneri). PNMGL2 was pH resistant (pH 2-9), heat stable (121 °C, 30 min), and protease sensitive. Treatment of UV rays, sodium chloride and organic solvents did not decrease the activity. Sequencing of the whole genome of L. plantarum NMGL2 revealed presence of a bacteriocin gene cluster with two putative bacteriocin genes (ORF4 and ORF5) that were not expressed, confirming the significance of PNMGL2 contributing the antimicrobial activity of the strain. This study demonstrated the low-molecular-weight AMP that was uncharacterized in the relevant available databases, suggesting its potential application as a novel natural food preservative.

Four Different Structural Dietary Polyphenols, Especially Dihydromyricetin, Possess Superior Protective Effect on Ethanol-Induced ICE-6 and AML-12 Cytotoxicity: The Role of CYP2E1 and Keap1-Nrf2 Pathways

Polyphenols have received attention as dietary supplements for the relief of alcoholic liver disease (ALD) due to various bioactivities. Ethanol-induced rat small intestinal epithelial cell 6 (IEC-6) and alpha mouse liver 12 (AML-12) cell models were pretreated with four dietary polyphenols with different structures to explore their effects on cytotoxicity and potential protective mechanisms. The results showed that polyphenols had potential functions to inhibit ethanol-induced AML-12 and IEC-6 cell damage and oxidative stress, and restore ethanol-induced IEC-6 permeability and tight junction gene expression. Especially, dihydromyricetin (DMY) had the best protective effect on ethanol-induced cytotoxicity, followed by apigenin (API). Western blot results showed that DMY and API had the best ability to inhibit CYP2E1 and Keap1, and promote nuclear translocation of Nrf2, which might be the potential mechanism by which DMY and API attenuate ethanol-induced cytotoxicity. Moreover, the molecular docking results predicted that DMY and API could bind more tightly to the amino acid residues of CYP2E1 and Keap1, which might be one of the inhibitory modes of dietary polyphenols on CYP2E1 and Keap1. This study provided a rationale for the subsequent protective effect of dietary polyphenols on alcohol-induced liver injury in animal models and provided new clues on bioactive components for ALD-protection based on the gut-liver axis.

A comparison of mining methods to extract novel bacteriocins from Lactiplantibacillus plantarum NWAFU-BIO-BS29

One of the most important challenges in the field of food safety is producing natural and safe substances that act against pathogens in food. Bacteriocins and antimicrobial peptides (AMPs) have an anti-pathogens effect for both Gram-negative and positive bacteria. The aim of this study was to isolate and characterize safe lactic acid bacteria from traditional Chinese fermented milk that can produce anti-bacterial molecule compounds and does not harm for humans and animals. Lactiplantibacillus plantarum NWAFU-BIO-BS29 was found to be safe, lacking 16 genes for virulence factors, biogenic amine production and antibiotic resistance, and no hemolysis activity was observed. In contrast, it has ability to produce a novel potential bacteriocin of Plantaricin Bio-LP1. Precipitation of bacteriocin by Ethyl-acetate proved to be a suitable method for the extraction the bacteriocin. Whilst, the purification steps were performed as follows: the protein purification system (AKTA-Purifier equipped with HiTrap (gel column)), followed by reversed phase high-performance liquid chromatography (RP-HPLC) equipped with C18 column. In addition, LC-MS-MS and MALDI-TOF were used to identify the peptide sequences and estimate the molecular weight, respectively. Notably, among the eight peptide sequences considered, a couple of sequences have been announced as uncharacterized in protein database (FDYYFFDKK and KEIDDNSIAVK) with a molecular mass less than 1.3 kDa. The MIC was 0.552 mg/ml and exhibited high stability under various temperature, pH, and enzymes conditions. The best activity was found at temperature and pH of 4 °C and 6 °C, respectively, which are the optimal conditions for preservation of most foods. We concluded that, the described method can arouse a growing interest in mining novel bacteriocins. Plantaricin Bio-LP1 is a potentially unique bacteriocin that is effective as a bio-preservative and could make a promising contribution in food and animal feed industries or in the medical field with further clinical studies.

Transcriptomic Analysis Revealed Antimicrobial Mechanisms of Lactobacillus rhamnosus SCB0119 against Escherichia coli and Staphylococcus aureus

Lactic acid bacteria were reported as a promising alternative to antibiotics against pathogens. Among them, Lactobacillus rhamnosus could be used as probiotics and inhibit several pathogens, but its antibacterial mechanisms are still less known. Here, L. rhamnosus SCB0119 isolated from fermented pickles could inhibit bacterial growth or even cause cell death in Escherichia coli ATCC25922 and Staphylococcus aureus ATCC6538, which was mainly attributed to the cell-free culture supernatant (CFS). Moreover, CFS induced the accumulation of reactive oxygen species and destroyed the structure of the cell wall and membrane, including the deformation in cell shape and cell wall, the impairment of the integrity of the cell wall and inner membrane, and the increases in outer membrane permeability, the membrane potential, and pH gradient in E. coli and S. aureus. Furthermore, the transcriptomic analysis demonstrated that CFS altered the transcripts of several genes involved in fatty acid degradation, ion transport, and the biosynthesis of amino acids in E. coli, and fatty acid degradation, protein synthesis, DNA replication, and ATP hydrolysis in S. aureus, which are important for bacterial survival and growth. In conclusion, L. rhamnosus SCB0119 and its CFS could be used as a biocontrol agent against E. coli and S. aureus.

Wheat supplement with buckwheat affect gut microbiome composition and circulate short-chain fatty acids

Buckwheat has beneficial effects on human intestinal health, which is often compounded with wheat to make food. Therefore, the effect of cereals mixture via in vitro fermentation on gut microbes and short-chain fatty acids (SCFAs) were investigated in this study. The mixture of wheat and tartary buckwheat (WT) produced more lactate and acetate, and the mixture of wheat and sweet buckwheat (WE) produced more propionate and butyrate. Compared with wheat (WA), the relative abundance of some beneficial bacteria significantly increased, such as Sutterella in WT and Faecalibacterium in WE. Cereals mixture also affected the expression of functional genes, involved in metabolic pathways and carbohydrate-active enzymes (CAZymes) that modulated SCFAs generation. This study provides new insights into the effects of sweet and tartary buckwheat on intestinal function, which is beneficial to applying both types of buckwheat in practical.

Comparison and Characterization of the Structure and Physicochemical Properties of Three Citrus Fibers: Effect of Ball Milling Treatment

Effects of ball milling (BM) on the structure and physicochemical properties of three types of citrus fibers were investigated. With the extension of the grinding time, the particle size of citrus fibers significantly decreased. Fourier transform infrared spectroscopy (FTIR) showed that the three citrus fibers had similar chemical groups, and more -OH and phenolic acid groups were exposed after BM, and pectin and lignin were not degraded. Scanning electron microscope (SEM) results showed that the appearance of particles changed from spherical to fragmented, irregular shapes. The water holding capacity (WHC), oil holding capacity (OHC), and water swelling capacity (WSC) of citrus fibers LM, JK, and FS reached the maximum value after BM of 2 h (increasing by 18.5%), 4 h (increasing by 46.1%), and 10 h (increasing by 38.3%), respectively. After 10 h BM, citrus fibers FS and JK had the highest adsorption capacity of cholesterol and sodium cholate, increasing by 48.3% and 48.6%, respectively. This indicates that BM transforms the spatial structure of citrus fibers and improves their physicochemical properties.

Soybean-Oil-Body-Substituted Low-Fat Ice Cream with Different Homogenization Pressure, Pasteurization Condition, and Process Sequence: Physicochemical Properties, Texture, and Storage Stability

The purpose of this research was to explore the impacts of different homogenization pressures, pasteurization conditions, and process sequence on the physical and chemical properties of soybean oil body (SOB)-substituted low-fat ice cream as well as the storage stability of SOB-substituted ice cream under these process parameters. With the increase of homogenization pressure (10–30 MPa), the increase of pasteurization temperature (65 °C for 30 min–85 °C for 15 min), and the addition of SOB before homogenization, the overrun and apparent viscosity of ice cream increased significantly, and the particle size, hardness, and melting rate decreased significantly. Thus, frozen dairy products of desired quality and condition could be obtained by optimizing process parameters. In addition, the SOB ice cream showed better storage stability, which was reflected in lower melting rate and hardness and more stable microstructure compared with the full-milk-fat ice cream. This study opened up new ideas for the application of SOB and the development of nutritious and healthy ice cream. Meanwhile, this research supplied a conceptual basis for the processing and quality optimization of SOB ice cream.

Physicochemical properties and bioactivity of polysaccharides from Isaria cicadae Miquel with different extraction processes: effects on gut microbiota and immune response in mice

The effect of different extraction processes on the physicochemical characterization, digestibility, antioxidant activity and prebiotic activity of Isaria cicadae Miquel (ICM) fruiting body polysaccharides was studied. Furthermore, the effect of ultrasound-assisted extraction of ICM (U-ICM) on gut microbiota, the intestinal barrier and immune response was deeply explored. This study found that ICMs showed high indigestibility in both α-amylase and artificial gastric juice, indicating that ICMs have the potential as dietary fiber. In contrast, U-ICM had the best antioxidant activity and prebiotic potential. Meanwhile, there was a structure-activity relationship between the antioxidant activity of ICMs and the content of uronic acid, arabinose and galactose. When healthy mice were fed U-ICM for 42 days, the relative abundances of Lactobacillus, Akkermansia, and Bacteroides were found to increase significantly, while that of Clostridium decreased significantly. Meanwhile, U-ICM significantly promotes the expression of tight junction protein and the production of cytokines, indicating that U-ICM had the function of enhancing the intestinal barrier and regulating the host immune response. In conclusion, U-ICM as dietary fiber has the potential to be developed as a gut health-promoting prebiotic component or functional food. This research provided a valuable resource for further exploring the structure-activity relationship and prebiotic activity of ICMs.

Anticandidal and Antibiofilm Effect of Synbiotics including Probiotics and Inulin-Type Fructans

Background: There is great interest in the search for new alternatives to antimicrobial drugs, and the use of synbiotics is a promising approach to this problem. This study evaluated the growth inhibition and antibiofilm activity of the short-chain fatty acids produced by Lacticaseibacillus rhamnosus and Pediococcus acidilactici in combination with inulin-type fructans against Candida albicans. Methods: The growth inhibition of Candida was evaluated using microdilution analysis in 96-well microtiter plates; different concentrations of cell-free supernatants of Lacticaseibacillus rhamnosus and Pediococcus acidilactici were exposed to Candida albicans. The antibiofilm assessment was carried out using the crystal violet staining assay. The short-chain fatty acids were analyzed by gas chromatography. Results: The clinically isolated Candida albicans interacted with supernatants from Lacticaseibacillus rhamnosus and Pediococcus acidilactici and showed significant growth inhibition and antibiofilm formation versus the controls. Lactate and acetic acid were elevated in the supernatants. The results suggest that the supernatants obtained from the synbiotic combinations of Lacticaseibacillus rhamnosus and Pediococcus acidilactici with inulin-type fructans can inhibit the growth and biofilm formation against a clinically isolated Candida albicans strain. Conclusions: These results suggest that synbiotic formulations could be a promising alternative to antifungal drugs in candidiasis therapy.

Antimicrobial, anti-biofilm, antioxidant and cytotoxic effects of bacteriocin by Lactococcus lactis strain CH3 isolated from fermented dairy products-An in vitro and in silico approach

The current study aimed to screen bacteriocin producing LAB from different dairy products and evaluation of their biological properties. Initially, 12 (4-chess, 4-curd, and 4-yohurt) LAB species were isolated and only 4 isolates alone were selected based on their clear yellow halo zone around the colonies in the selective medium. The selected 4 isolates were identified based on their morphological and biochemical characteristics. Among them, the strain CH3 have showed better antimicrobial effects on selected human pathogens. The isolated strain CH3 were further identified as Lactococcus lactis strain CH3 (MZ636710) by SEM imaging and 16 s rRNA molecular sequencing. Bacteriocin was extracted from L. lactis strain CH3 and partially purified using 60 % ammonium sulphate and then completely purified by G-50 column chromatography. The purified bacteriocin showed a specific activity of 5859.37 AU/mg in 24.7 % of recovery and 10.9-fold purification. The molecular weight of bacteriocin was 3.5 kDa as observed in SDS-PAGE. The bacteriocin showed sensitivity to proteolytic enzymes and resistance to high temperature, wide range of pH, organic solvents and detergents. FT-IR spectral studies of bacteriocin detected the existence of OH/NH-stretching, CH, and COC and CO bonds. NMR spectrum showed one doublet and 4 various singlet peaks at different ppm, indicating the occurrence of six amino acids in the structure of purified bacteriocin. The purified bacteriocin have shown stronger antimicrobial and anti-biofilm activity against selected human pathogens at 100 μg/mL. SEM showed the evidence of structural deformation and loss of membrane integrity of bacterial cells treated with bacteriocin. Bacteriocin exhibited greater DPPH radical scavenging potential with an EC₅₀ value of 12.5 μg/mL. Bacteriocin have not shown significant toxicity on normal human dermal fibroblast (NHDF) cells (83.2 % at 100 μg/ mL). Furthermore, in silico studies using molecular modeling and docking were performed to know the proteins involved in antimicrobial action. The results suggests that bacteriocin could be an alternative to combat AMR pathogens and more suitable for food and dairy industries to preserve food without contamination.

Effects of Lactobacillus plantarum HFY15 on Lupus Nephritis in Mice by Regulation of the TGF-β1 Signaling Pathway

Objective

In this study, the Lactobacillus plantarum HFY15 (LP-HFY15) strain isolated from naturally fermented yak yogurt was investigated. An animal model of lupus nephritis was established by pristane to verify the interventional effect of LP-HFY15 on mouse lupus nephritis by regulating the transforming growth factor-β1 (TGF-β1) signaling pathway.

Materials and Methods

Indexes in mouse serum and tissues were detected by kits, pathological changes in mouse kidney were observed by hematoxylin-eosin (H&E) staining, and quantitative polymerase chain reaction (qPCR) was used to detect TGF-β 1-related expression in mouse kidney tissue, which further elucidated the mechanism of LP-HFY15.

Results

LP-HFY15 decreased the elevation of urinary protein and the levels of interleukin-6 (IL-6), IL-12, tumor necrosis factor alpha (TNF-α), and interferon γ (IFN-γ) in serum and kidney tissue. LP-HFY15 also reduced serum creatinine (SCr), blood urea nitrogen (BUN), total cholesterol (TC), triglyceride (TG), and raised total protein (TP), and albumin (ALB) levels in mice with nephritis. In addition, LP-HFY15 inhibited the positive rate of double-stranded deoxyribonucleic acid (dsDNA) antibodies in mice with nephritis. The observation of H&E sections showed that LP-HFY15 alleviated the glomerulus morphological incompleteness and inflammatory infiltration caused by nephritis. Further results showed that LP-HFY15 downregulated the mRNA expression of TGF-β1, vascular endothelial growth factor (VEGF), and nuclear factor kappa-B (NF-κB) in the kidneys of lupus nephritis mice, and the expression of inhibitor of NF-κB (IκB-α), copper/zinc superoxide dismutase (Cu/Zn-SOD), and manganese superoxide dismutase (Mn-SOD) was also upregulated.

Conclusion

These results indicated that LP-HFY15 plays a significant role in experimental intervention for lupus nephritis. The effect of LP-HFY15 was positively correlated with its concentration, and the effect was similar to that of prednisone at 10⁹ CFU/kg.

Physicochemical Properties, Stability and Texture of Soybean-Oil-Body-Substituted Low-Fat Mayonnaise: Effects of Thickeners and Storage Temperatures

With the increasing consumer demand for low-fat and low-cholesterol foods, low-fat mayonnaise prepared from soybean oil body (SOB) substitute for egg yolk has great consumption potential. However, based on previous studies, it was found that the stability and sensory properties of mayonnaise substituted with SOB were affected due to there being less lecithin and SOB containing more water. Therefore, this study investigated the effects of different ratios of xanthan gum, pectin and modified starch as stabilizers on the apparent viscosity, stability, texture and microstructure of SOB-substituted mayonnaise. It was found that the apparent viscosity and stability of SOB-substituted mayonnaise increased significantly when xanthan gum, pectin and modified starch were added in a ratio of 2:1:1. Meanwhile, the emulsified oil droplets of SOB-substituted mayonnaise were similar in size and uniformly dispersed in the emulsion system with different thickener formulations. In addition, the storage stability of SOB-substituted mayonnaise was explored. Compared with full egg yolk mayonnaise, SOB-substituted mayonnaise had better oxidative stability and bacteriostatic, which is important for the storage of mayonnaise. This study provided a theoretical basis for the food industry application of SOB. Meanwhile, this study provided new ideas for the development and storage of low-fat mayonnaise.

Lactobacillus plantarum Combined with Galactooligosaccharides Supplement: A Neuroprotective Regimen Against Neurodegeneration and Memory Impairment by Regulating Short-Chain Fatty Acids and the c-Jun N-Terminal Kinase Signaling Pathway in Mice

Probiotics and prebiotics have received attention in alleviating neurodegenerative diseases. Lactobacillus plantarum (L. plantarum) 69-2 was combined with galactooligosaccharides (GOS) and supplemented in a d-galactose (d-gal)-induced neurodegeneration and memory impairment mice model to explore its effects on the brain and the regulation of short-chain fatty acids. The results showed that the L. plantarum-GOS supplementation inhibited d-gal-induced oxidative stress and increased the brain's nuclear factor erythroid 2-related factor 2 (Nrf2) levels. Butyrate, a metabolite of the gut microbiota regulated by L. plantarum combined with GOS, inhibits p-JNK expression, downregulates pro-apoptotic proteins expression and the activation of inflammatory mediators, and upregulates synaptic protein expression. This might be a potential mechanism for L. plantarum 69-2 combined with GOS supplementation to alleviate d-gal-induced neurodegeneration and memory impairment. This study sheds new light on the development of aging-related neuroprotective dietary supplements based on the gut-brain axis.

Soybean Oil Bodies as a Milk Fat Substitute Improves Quality, Antioxidant and Digestive Properties of Yogurt

In this experiment, the effect of replacing milk fat with soybean fat body (25%, 50%, 75%, 100%) on the quality, antioxidant capacity and in vitro digestive characteristics of yogurt was investigated while maintaining the total fat content of the yogurt unchanged. The results showed that increasing the substitution amount of soy fat body for milk fat had little effect on the pH and acidity of yogurt during the storage period, while the physicochemical properties, degree of protein gel network crosslinking, saturated fatty acid content, PV value and TBARS value of the yogurt significantly decreased (p < 0.05). Meanwhile, protein content, solids content, unsaturated fatty acid content, tocopherol content and water holding capacity significantly increased (p < 0.05). Flavor analysis revealed that yogurts with soybean oil bodies were significantly different when compared to those without soybean oil bodies (p < 0.05), and yogurt with 25% substitution had the highest sensory score. After in vitro digestion, the free fatty acid release, antioxidant capacity and protein digestibility of soybean oil body yogurt were significantly higher (p < 0.05). The SDS-PAGE results showed that the protein hydrolysis of the soybean oil body yogurt was faster. Therefore, the use of an appropriate amount of soybean oil bodies to replace milk fat is able to enhance the taste of yogurt and improve the quality of the yogurt.

Novel nano-encapsulated probiotic agents: Encapsulate materials, delivery, and encapsulation systems

Gut microbes are closely associated with most human health. When ingested orally, probiotics can effectively regulate the composition and quantity of human intestinal microorganisms, which is beneficial to human health. However, probiotics will be affected by the harsh environment of the digestive tract during the in vivo transportation process, and ensuring the viability of probiotics is a great challenge. Probiotic encapsulating technology provides an effective solution to this problem. The introduction of extreme temperatures, large probiotic microcapsule sizes and the difficulty in controlling probiotic microcapsule particle sizes mean that traditional microcapsule encapsulation methods have some limitations. From traditional microcapsule technology to the bulk encapsulation of probiotics with nanofibers and nanoparticles to the recent ability to wear nano "armor" for a single probiotic through biofilm, biological membrane and nanocoating. Emerging probiotic nanoagents provides a new conceptual and development direction for the field of probiotic encapsulation. In this review, we presented the characteristics of encapsulated probiotic carrier materials and digestive tract transport systems, we focused on the encapsulation systems of probiotic nanoagents, we analyzed the shortcomings and advantages of the current agent encapsulation systems, and we stated the developmental direction and challenges for these agents for the future.

Comparison of Oxidative and Physical Stabilities of Conjugated Linoleic Acid Emulsions Stabilized by Glycosylated Whey Protein Hydrolysates via Two Pathways

The objective of the research was to analyze and compare the oxidative and physical stabilities of conjugated linoleic acid (CLA) emulsions stabilized by two glycosylated hydrolysates (GPP-A and GPP-B) that were formed via two different pathways. This study showed that GPP-A exhibited higher browning intensity and DPPH radical scavenging ability in comparison with GPP-B. Moreover, the CLA emulsion formed by GPP-A exhibited a lower creaming index, average particle size, primary and secondary oxidative products, in comparison with GPP-B-loaded emulsion. However, the GPP-A-loaded emulsion showed a higher absolute potential and fraction of interfacial adsorption than that of the CLA emulsion formed by GPP-B. Therefore, the CLA emulsion formed by GPP-A exhibited stronger stabilities in comparison with the GPP-B-loaded emulsion. These results suggested that GPP-A showed an emulsification-based delivery system for embedding CLA to avoid the loss of biological activities. Additionally, the development of CLA emulsions could exert its physiological functions and prevent its oxidation.

Lactobacillus plantarum 23-1 improves intestinal inflammation and barrier function through the TLR4/NF-κB signaling pathway in obese mice

As a natural active ingredient, lactic acid bacteria have potential anti-inflammatory effects. In this study, male C57BL/6J mice were given a high-fat diet (HFD) to establish an obese mouse model. Lactobacillus plantarum 23-1 (LP23-1) with prebiotic characteristics was intervened for 8 weeks to evaluate its remission effect on obese animals and related mechanisms. The effects of LP23-1 on lipid accumulation and intestinal inflammation in HFD-fed mice were systematically evaluated by detecting lipid accumulation, blood lipid level, pathological changes in the liver and small intestine, oxidative stress and inflammatory cell level, lipid transport-related gene expression, the inflammatory signaling pathway, and intestinal tight junction (TJ) mRNA and protein expression. The results showed that LP23-1 could significantly reduce the body weight and fat index of HFD-fed mice, improve the lipid levels of serum and liver, reduce the histopathological damage to the liver and small intestine, and alleviate oxidative stress and inflammatory response caused by obesity. In addition, reverse transcription-polymerase chain reaction and western blot analysis showed that LP23-1 could regulate the mRNA expression of lipid transport-related genes; activate the TLR4/NF-κB signaling pathway; reduce intestinal inflammation; improve the mRNA and protein expression of intestinal TJ proteins zona occludens-1 (ZO-1), occludin, claudin-1, and Muc2; repair intestinal mucosal injury; and enhance intestinal barrier function. The aforementioned results showed that LP23-1 through the TLR4/NF-κB signaling pathway and intestinal barrier function reduced obesity symptoms. This study provided new insights into the mechanism of LP23-1 in reducing obesity and provided a theoretical basis for developing new functional foods.

Effects of Soybean Oil Body as a Milk Fat Substitute on Ice Cream: Physicochemical, Sensory and Digestive Properties

Soybean oil body (SOB) has potential as a milk fat substitute due to its ideal emulsification, stability and potential biological activity. In this study, SOB was used as a milk fat substitute to prepare ice cream, expecting to reduce the content of saturated fatty acid and improve the quality defects of ice cream products caused by the poor stability of milk fat at low temperatures. This study investigated the effect of SOB as a milk fat substitute (the substitution amount was 10–50%) on ice cream through apparent viscosity, particle size, overrun, melting, texture, sensory and digestive properties. The results show SOB substitution for milk fat significantly increased the apparent viscosity and droplet uniformity and decreased the particle size of the ice cream mixes, indicating that there were lots of intermolecular interactions to improve ice cream stability. In addition, ice cream with 30% to 50% SOB substitution had better melting properties and texture characteristics. The ice cream with 40% SOB substitution had the highest overall acceptability. Furthermore, SOB substitution for milk fat increased unsaturated fatty acid content in ice cream and fatty acid release during digestion, which had potential health benefits for consumers. Therefore, SOB as a milk fat substitute may be an effective way to improve the nutritional value and quality characteristics of dairy products.

Isolation and Characterization of Bacteriocin-Producing Lacticaseibacillus rhamnosus XN2 from Yak Yoghurt and Its Bacteriocin

Lactic acid bacteria (LAB) produce antimicrobial substances that could potentially inhibit the growth of pathogenic and food spoilage microorganisms. Lacticaseibacillus rhamnosus XN2, isolated from yak yoghurt, demonstrated antibacterial activity against Bacillus subtilis, B. cereus, Micrococcus luteus, Brochothrix thermosphacta, Clostridium butyricum, S. aureus, Listeria innocua CICC 10416, L. monocytogenes, and Escherichia coli. The antibacterial activity was estimated to be 3200 AU/mL after 30 h cultivation. Time-kill kinetics curve showed that the semi-purified cell-free supernatants (CFS) of strain XN2 possessed bactericidal activity. Flow cytometry analysis indicated disruption of the sensitive bacteria membrane by semi-purified CFS, which ultimately caused cell death. Interestingly, sub-lethal concentrations of semi-purified CFS were observed to reduce the production of α-haemolysin and biofilm formation. We further investigated the changes in the transcriptional level of luxS gene, which encodes signal molecule synthase (Al-2) induced by semi-purified CFS from strain XN2. In conclusion, L. rhamnosus XN2 and its bacteriocin showed antagonistic activity at both cellular and quorum sensing (QS) levels. Finally, bacteriocin was further purified by reversed-phase high-performance liquid chromatography (RP-HPLC), named bacteriocin XN2. The amino acid sequence was Met-Lue-Lys-Lys-Phe-Ser-Thr-Ala-Tyr-Val.

Combating biofilms of foodborne pathogens with bacteriocins by lactic acid bacteria in the food industry

Most foodborne pathogens have biofilm-forming capacity and prefer to grow in the form of biofilms. Presence of biofilms on food contact surfaces can lead to persistence of pathogens and the recurrent cross-contamination of food products, resulting in serious problems associated with food safety and economic losses. Resistance of biofilm cells to conventional sanitizers urges the development of natural alternatives to effectively inhibit biofilm formation and eradicate preformed biofilms. Lactic acid bacteria (LAB) produce bacteriocins which are ribosomally synthesized antimicrobial peptides, providing a great source of nature antimicrobials with the advantages of green and safe properties. Studies on biofilm control by newly identified bacteriocins are increasing, targeting primarily onListeria monocytogenes, Staphylococcus aureus, Salmonella, and Escherichia coli. This review systematically complies and assesses the antibiofilm property of LAB bacteriocins in controlling foodborne bacterial-biofilms on food contact surfaces. The bacteriocin-producing LAB genera/species, test method (inhibition and eradication), activity spectrum and surfaces are discussed, and the antibiofilm mechanisms are also argued. The findings indicate that bacteriocins can effectively inhibit biofilm formation in a dose-dependent manner, but are difficult to disrupt preformed biofilms. Synergistic combination with other antimicrobials, incorporation in nanoconjugates and implementation of bioengineering can help to strengthen their antibiofilm activity. This review provides an overview of the potential and application of LAB bacteriocins in combating bacterial biofilms in food processing environments, assisting in the development and widespread use of bacteriocin as a promising antibiofilm-agent in food industries.

Novel pathways in bacteriocin synthesis by lactic acid bacteria with special reference to ethnic fermented foods

Ethnic fermented foods are known for their unique aroma, flavour, taste, texture and other sensory properties preferred by every ethnic community in this world culturally as parts of their eatables. Some beneficial microorganisms associated with fermented foods have several functional properties and health-promoting benefits. Bacteriocins are the secondary metabolites produced by the microorganisms mostly lactic acid bacteria present in the fermented foods which can act as lantibiotics against the pathogen bacteria. Several studies have been conducted regarding the isolation and characterization of potent strains as well as their association with different types of bacteriocins. Collective information regarding the gene organizations responsible for the potent effect of bacteriocins as lantibiotics, mode of action on pathogen bacterial cells is not yet available. This review focuses on the gene organizations, pathways include for bacteriocin and their mode of action for various classes of bacteriocins produced by lactic acid bacteria in some ethnic fermented foods.

Distribution of Genes Related to Probiotic Effects Across Lacticaseibacillus rhamnosus Revealed by Population Structure

The Gram-positive Lacticaseibacillus rhamnosus has been broadly reported as capable of exerting beneficial health effects. Bacterial genomic diversity may promote niche specialization, thus creating subpatterns within populations. As L. rhamnosus advantageous effects have been widely reported at strain level and few is known regarding the distribution of beneficial genes among L. rhamnosus strains, we investigated all publicly available genomes of Lactobacillus and Lacticaseibacillus genera to study the pangenome and general population structure of L. rhamnosus. Core genome multilocus sequence typing detected eight L. rhamnosus phylogroups (PG1 to PG8). L. rhamnosus harbors an open pangenome; PG1, PG3, PG4, and PG5 exhibited highly conserved gene distribution patterns. Genes significantly associated to the PG1, which comprises L. rhamnosus GG, are mainly phage-related. The adhesion operon spaCBA-srtC1 was found in 44 (24.7%) genomes; however, considering only the PG1, the prevalence was of 65%. In PG2 the spaCBA-srtC1 prevalence was of 43%. Nevertheless, both human and milk-derived strains harbored this operon. Further, two main types of bacteriocin clusters were found (Bact1 and Bact2). Bact1 predictions indicate the presence of garQ, encoding the class II bacteriocin garvieacin Q, that is mainly present in the closely related PG8A and a PG2 subcluster. PG2 harbors two distinct subclusters, harboring either spaCBA-srtC1 or Bact1. Our findings provide novel insights on the distribution of biotechnological relevant genes across L. rhamnosus population, uncovering intra-species patterns that may bring forth the development of more efficient probiotic products.

Evaluation of the antibacterial effects and mechanism of Plantaricin 149 from Lactobacillus plantarum NRIC 149 on the peri-implantitis pathogens

Peri-implantitis is a common reversible disease after tooth implantation, caused by a variety of pathogenic microorganisms. Based on non-surgical or surgical treatment principles, supplementation by local or systemic drugs might enhance treatment efficacy. Porphyromonas gingivalis (Pg) (ATCC 33,277) and Prevotella intermedius (Pi) (ATCC 25,611) were used as test strains. The effects of Pln 149 on the biofilm formation and growth of four periodontal pathogens were evaluated by RT-PCR, fluorescence microscopy, and scanning electron microscopy. The antibacterial mechanism was tested by the patch-clamp technique. The cytotoxicity of Pln 149 (125 µg/ml) to bone marrow stromal cell (BMSC) was assessed using an MTT assay. Pln 149 exhibited significant inhibitory effects on Pg and Pi (P < 0.05), with significant differences in the biofilm images of fluorescence microscope and scanning electron microscope (P < 0.05). Pln 149 could change the sodium channel currents and exerted no cytotoxicity on bone marrow stromal cell. Pln 149 could inhibit the biofilm formation and growth of periodontal pathogens. Considering the absence of antimicrobial resistance and cytotoxicity, we suggest that the Pln 149 from Lactobacillus plantarum 149 might be a promising option for managing peri-implantitis.