Isolation of Lactic Acid Bacteria from Naturally Ensiled Rosa roxburghii Tratt Pomace and Evaluation of Their Ensiling Potential and Antioxidant Properties

This study isolated five acid-producing strains (XQ1 and YZ1-YZ4) from naturally fermented pomace of Rosa roxburghii Tratt (RRT) in Guizhou's karst region. Genetic and phenotypic analyses identified XQ1, YZ2, and YZ4 as Lactobacillus plantarum (L. plantarum), YZ3 as Weissella cibaria, and YZ1 as Bacillus licheniformis. A comparative evaluation with commercial strain AC revealed that XQ1, YZ2, and YZ4 exhibited superior acidification (reaching the stationary phase at 40 h) and tolerance to acidic conditions (pH 3.0), ethanol (6% v/v), bile salts (0.3%), and osmotic stress (6.5% NaCl), along with broad-spectrum antimicrobial activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Shigella dysenteriae, and Pseudomonas aeruginosa. Their cell-free supernatants (CFSs) showed comparable superoxide dismutase activity and total antioxidant capacity (2.54-2.66 FeSO4·7H2O eq mmol/L) to AC (2.68), with DPPH radical scavenging exceeding 50%. YZ3 displayed weaker acid production, tolerance, and limited antimicrobial effects. Safety assessments confirmed non-hemolytic activity and antibiotic susceptibility. In conclusion, the L. plantarum strains XQ1, YZ2, and YZ4 demonstrated strong ensiling potential and remarkable probiotic properties, establishing them as promising indigenous microbial resources for the preservation of RRT pomace and other food products.

The Effects of Different Probiotic Administration on Dexamethasone-Associated Metabolic Effects

Glucocorticoids are steroid hormones used in clinical practice as an effective therapeutic option for their effects regarding the dysregulated immune reactions and hyperactive immune system. Their administration in the short- and long-term exposure has been associated with numerous metabolic side effects. Probiotics have been shown to modulate basal metabolism, inflammation, and oxidative stress through the regulation of composition and function of the gut microbial environment. The aim of this study was to assess the effects of Saccharomyces boulardii and Lactobacillus paracasei probiotics in dexamethasone-treated rats. The study comprised four groups, with 6 Charles River Wistar albino male rats/group; group 1 represented the negative control, rats from group 2 were administered dexamethasone, rats from group 3 were administered dexamethasone and probiotics containing the strain Saccharomyces boulardii, and rats from group 4 were administered dexamethasone and probiotics containing the strain Lactobacillus paracasei. We have assessed the plasmatic levels of glucose, total cholesterol, triglycerides, tumor necrosis factor-alpha, interleukin-10, catalase activity, and total antioxidant capacity. The administration of dexamethasone led to elevated serum concentrations of glycolipid metabolism parameters and cytokines and resulted in hepatic steatosis at the morphological level. Administration of probiotics containing Saccharomyces boulardii or Lactobacillus paracasei reduced glucose and tumor necrosis factor-alpha serum concentration in dexamethasone-treated rats. Moreover, the administration of Lactobacillus paracasei probiotics in rats that received dexamethasone increased interleukin-10 and reduced catalase activity. Regarding the liver tissue morphology, the rats that received probiotics showed improved liver histological aspects compared to the dexamethasone-treated group, suggesting that probiotics could provide positive effects regarding the metabolic and histological disturbances induced by glucocorticoids.

Probiotic, Postbiotic, and Paraprobiotic Effects of Lactobacillus rhamnosus as a Modulator of Obesity-Associated Factors

Obesity is a pandemic currently affecting the world's population that decreases the quality of life and promotes the development of chronic non-communicable diseases. Lactobacillus rhamnosus is recognized for multiple positive effects on obesity and overall health. In fact, such effects may occur even when the microorganisms do not remain alive (paraprobiotic effects). This raises the need to elucidate the mechanisms by which obesity-associated factors can be modulated. This narrative review explores recent findings on the effects of L. rhamnosus, particularly, its postbiotic and paraprobiotic effects, on the modulation of adiposity, weight gain, oxidative stress, inflammation, adipokines, satiety, and maintenance of intestinal integrity, with the aim of providing a better understanding of its mechanisms of action in order to contribute to streamlining its clinical and therapeutic applications. The literature shows that L. rhamnosus can modulate obesity-associated factors when analyzed in vitro and in vivo. Moreover, its postbiotic and paraprobiotic effects may be comparable to the more studied probiotic actions. Some mechanisms involve regulation of gene expression, intracellular signaling, and enteroendocrine communication, among others. We conclude that the evidence is promising, although there are still multiple knowledge gaps that require further study in order to fully utilize L. rhamnosus to improve human health.

Anti-oxidative activity of probiotics; focused on cardiovascular disease, cancer, aging, and obesity

By disturbing the prooxidant-antioxidant balance in the cell, a condition called oxidative stress is created, causing severe damage to the nucleic acid, protein, and lipid of the host cell, and as a result, endangers the viability of the host cell. A relationship between oxidative stress and several different diseases such as cardiovascular diseases, cancer, and obesity has been reported. Therefore, maintaining this prooxidant-antioxidant balance is vital for the cell. Probiotics as one of the potent antioxidants have recently received attention. Many health-promoting and beneficial effects of probiotics are known, and it has been found that the consumption of certain strains of probiotics alone or in combination with food exerts antioxidant efficacy and reduces oxidative damage. Studies have reported that certain probiotic strains implement their antioxidant effects by producing metabolites and antioxidant enzymes, increasing the antioxidant capacity, and reducing host oxidant metabolites. Therefore, we aimed to review and summarize the latest anti-oxidative activity of probiotics and its efficacy in aging, cardiovascular diseases, cancer, and obesity.

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.

Genomic insights and functional evaluation of Lacticaseibacillus paracasei EG005: a promising probiotic with enhanced antioxidant activity

Introduction

Probiotics, such as Lacticaseibacillus paracasei EG005, are gaining attention for their health benefits, particularly in reducing oxidative stress. The goal of this study was to reinforce the antioxidant capacity of EG005, along with comprehensive genomic analysis, with a focus on assessing superoxide dismutase (SOD) activity, acid resistance and bile tolerance, and safety.

Methods

EG005 was screened for SOD activity and change of SOD activity was tested under various pH conditions. Its survival rates were assessed in acidic (pH 2.5) and bile salt (0.3%) conditions and the antibiotic MIC test and hemolysis test were performed to evaluate safety. Genetic analyses including functional identification and phylogenetic tree construction were performed. The SOD overexpression system was constructed using Ptuf, Pldh1, Plhd2, and Pldh3 strong promoters.

Results

EG005 demonstrated higher SOD activity compared to Lacticaseibacillus rhamnosus GG, with optimal activity at pH 7.0. It showed significant acid and bile tolerance, with survival rates recovering to 100% after 3 h in acidic conditions. Phylogenetic analysis confirmed that EG005 is closely related to other L. paracasei strains with ANI values above 98%. Overexpression of SOD using the Ptuf promoter resulted in a two-fold increase in activity compared to the controls. Additionally, EG005 exhibited no hemolytic activity and showed antibiotic susceptibility within safe limits.

Discussion

Our findings highlight EG005's potential as a probiotic with robust antioxidant activity and high tolerance to gastrointestinal conditions. Its unique genetic profile and enhanced SOD activity through strong promoter support its application in probiotic therapies and functional foods. Further research should be investigated to find the in vivo effects of EG005 on gut health and oxidative stress reduction. In addition, attB and attP-based recombination, combined with CRISPR-Cas9 technologies, could offer a more stable alternative for long-term sodA gene expression in commercial and medical applications.

Evaluating the Probiotic Profile, Antioxidant Properties, and Safety of Indigenous Lactobacillus spp. Inhabiting Fermented Green Tender Coconut Water

This study isolated and characterized four indigenous lactic acid bacterial strains from naturally fermented green tender coconut water: Lactiplantibacillus plantarum CWJ3, Lacticaseibacillus casei CWM15, Lacticaseibacillus paracasei CWKu14, and Lacticaseibacillus rhamnosus CWKu-12. Notably, among the isolates, Lact. plantarum CWJ3 showed exceptional acid tolerance, with the highest survival rate of 37.34% at pH 2.0 after 1 h, indicating its higher resistance against acidic gastric conditions. However, all strains exhibited robust resistance to bile salts, phenols, and NaCl, with survival rates exceeding 80% at given concentrations. Their optimal growth at 37 °C and survival at 20 °C and 45 °C underscored adaptability to diverse environmental conditions. Additionally, all strains showed sustainable survival rates in artificial saliva and simulated gastrointestinal juices, with Lact. plantarum CWJ3 exhibiting significantly higher survival rate (70.66%) in simulated gastric juice compared to other strains. Adherence properties were particularly noteworthy, especially in Lact. rhamnosus CWKu-12, which demonstrated the highest hydrophobicity, coaggregation with pathogens and autoaggregation, among the strains. The production of exopolysaccharides, particularly by Lact. plantarum CWJ3, enhanced their potential for gut colonization and biofilm formation. Various in vitro antioxidative assays using spectrophotometric methods revealed the significant activity of Lact. plantarum CWJ3, while antimicrobial testing highlighted its efficacy against selected foodborne pathogens. Safety assessments confirmed the absence of biogenic amine production, hemolytic, DNase, and gelatinase activities, as well as the ability to hydrolase the bile salt. Furthermore, these non-dairy probiotics exhibited characteristics comparable to dairy derived probiotics, demonstrating their potential suitability in developing novel probiotic-rich foods and functional products.

Candidate-Probiotic Lactobacilli and Their Postbiotics as Health-Benefit Promoters

Lactobacillus species are widely recognized for their probiotic potential, focusing on their mechanisms of health benefits and protection. Here we conducted an in vitro investigation of the probiotic potential with a role in microbiome homeostasis of four strains: Lactiplantibacillus plantarum L6 and F53, Ligilactobacillus salivarius 1, and Lactobacillus helveticus 611. A broad spectrum of antibacterial and antifungal activity was determined. The strain-specific inhibition of Staphylococcus aureus, Streptococcus mutans, Escherichia coli, Pseudomonas aeruginosa, and saprophytic/toxigenic fungi makes them promising as protective cultures. DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic) acid) measurements showed that tested samples had strain-specific capacity for scavenging of radicals. The molecular base for the antioxidant potential of two lyophilized forms of active strains was investigated by electron paramagnetic resonance spectroscopy. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, with fractions of the most active postbiotics obtained by SEC-FPLC (fast protein liquid chromatography) analysis, showed a wide variety of effects on the growth of a K562 myeloid leukemia cell line. The IC50 (half-maximal inhibitory concentration) of L. salivarius 1 was determined to be 46.15 mg/mL. The proven in vitro functionality of the selected lactobacilli make them suitable for development of target probiotics with specific beneficial effects expected in vivo. Further investigations on produced postbiotics and safety have to be completed before they can be considered as scientifically proven probiotic strains.

Mangosteen extracts: Effects on intestinal bacteria, and application to functional fermented milk products

Mangosteen (Garcinia mangostana L.) is a tasty, polyphenol-rich tropical fruit. The edible part is highly appreciated by its aroma, taste and texture. The non-edible part, rich in polyphenols, has been traditionally used in Thai medicine. In this work, flavonoids and phenolic acid/derivatives were identified in mangosteen extracts (ME) from edible and non-edible portions. We first studied the effects of MEs on the growth, metabolism, antioxidant capacity, biofilm formation and antimicrobial capacity of eight bifidobacteria and lactobacilli strains from intestinal origin and two commercial probiotic strains (BB536 and GG). ME concentrations higher than 10-20 % were inhibitory for all strains. However, ME concentrations of 5 % significantly (P < 0.01) increased all strains antioxidant capacity, reduced biofilm-formation, and enhanced inhibition against Gram-positive pathogens. To apply these knowledge, bifunctional fermented milk products were elaborated with 5 % ME and individual strains, which were selected taking into account their growth with ME, and the widest range of values on antioxidant capacity, biofilm formation and antimicrobial activity (bifidobacteria INIA P2 and INIA P467, lactobacilli INIA P459 and INIA P708, and reference strain GG). Most strains survived well manufacture, refrigerated storage and an in vitro simulation of major conditions encountered in the gastrointestinal tract. As expected, products supplemented with ME showed higher polyphenol content and antioxidant capacity levels than control. After sensory evaluation, products containing strains INIA P2, INIA P708 and GG outstood as best.

Gut bacterial composition shows sex-specific shifts during breeding season in ex situ managed black-footed ferrets

The gut microbiome of mammals engages in a dynamic relationship with the body and contributes to numerous physiological processes integral to overall health. Understanding the factors shaping animal-associated bacterial communities is therefore paramount to the maintenance and management in ex situ wildlife populations. Here, we characterized the gut microbiome of 48 endangered black-footed ferrets (Mustela nigripes) housed at Smithsonian's National Zoo and Conservation Biology Institute (Front Royal, Virginia, USA). We collected longitudinal fecal samples from males and females across two distinct reproductive seasons to consider the role of host sex and reproductive physiology in shaping bacterial communities, as measured using 16S rRNA amplicon sequencing. Within each sex, gut microbial composition differed between breeding and non-breeding seasons, with five bacterial taxa emerging as differentially abundant. Between sexes, female and male microbiomes were similar during non-breeding season but significantly different during breeding season, which may result from sex-specific physiological changes associated with breeding. Finally, we found low overall diversity consistent with other mammalian carnivores alongside high relative abundances of potentially pathogenic microbes such as Clostridium, Escherichia, Paeniclostridium, and (to a lesser degree) Enterococcus-all of which have been associated with gastrointestinal or reproductive distress in mammalian hosts, including black-footed ferrets. We recommend further study of these microbes and possible therapeutic interventions to promote more balanced microbial communities. These results have important implications for ex situ management practices that can improve the gut microbial health and long-term viability of black-footed ferrets.

Astragalus Polysaccharide Modulates the Gut Microbiota and Metabolites of Patients with Type 2 Diabetes in an In Vitro Fermentation Model

This study investigated the effect of astragalus polysaccharide (APS, an ingredient with hypoglycemic function in a traditional Chinese herbal medicine) on gut microbiota and metabolites of type 2 diabetes mellitus (T2DM) patients using a simulated fermentation model in vitro. The main components of APS were isolated, purified, and structure characterized. APS fermentation was found to increase the abundance of Lactobacillus and Bifidobacterium and decrease the Escherichia-Shigella level in the fecal microbiota of T2DM patients. Apart from increasing propionic acid, APS also caused an increase in all-trans-retinoic acid and thiamine (both have antioxidant properties), with their enrichment in the KEGG pathway associated with thiamine metabolism, etc. Notably, APS could also enhance fecal antioxidant properties. Correlation analysis confirmed a significant positive correlation of Lactobacillus with thiamine and DPPH-clearance rate, suggesting the antioxidant activity of APS was related to its ability to enrich some specific bacteria and upregulate their metabolites.

Improving the Antioxidant and Anti-Inflammatory Activity of Fermented Milks with Exopolysaccharides-Producing Lactiplantibacillus plantarum Strains

Exopolysaccharides (EPSs) producing lactic acid bacteria have been claimed to confer various health benefits to the host, including the ability to face oxidative and inflammatory-related stress. This study investigated the ability of food-borne Lactiplantibacillus (Lpb.) plantarum to improve the antioxidant activity of fermented milks by producing EPSs. Two Lpb. plantarum strains, selected as lower and higher EPSs producers, have been applied in lab-scale fermented milk production, in combination with conventional starters. Antioxidant activity was investigated in vitro using DPPH (1,1-diphenyl-2-picrylhydrazyl), ABTS (2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), and FRAP (ferric reducing antioxidant power) assays while the ability to modulate reactive oxygen species (ROS) level was evaluated in an intestinal healthy model, subjected to both oxidative and inflammatory stress. Furthermore, to verify whether digestion affects functionality, fermented milks were evaluated before and after in vitro-simulated INFOGEST digestion. The results showed an improved antioxidant activity of fermented milk enriched with Lpb. plantarum LT100, the highest EPSs producer. Furthermore, the data showed a different ROS modulation with a protective anti-inflammatory effect of samples enriched with Lpb. plantarum strains. Our data suggest the use of selected EPS-producing strains of Lpb. plantarum as a natural strategy to enrich the functionality of fermented milks in terms of ROS modulation and inflammatory-related stress.

Short-term use of Lacticaseibacillus rhamnosus SD11 and the oral microbiome: Low caries RCT study

OBJECTIVES

The objective of the study was to investigate the effect of short-term lozenges containing Lacticaseibacillus rhamnosus SD11 on cariogenic pathogens and on oral microbiota.

MATERIALS AND METHODS

This double-blind, randomized, controlled trial included 121 subjects and was randomly divided into the control and probiotic group. All subjects were blindly administered to receive the control- or probiotic L. rhamnosus SD11 lozenges every day for 4 weeks and then followed up for another 4 weeks.

RESULTS

After probiotic consumption, the probiotic group had significantly lower levels of Streptococcus mutans and significantly higher levels of total lactobacilli at 4 and 8 weeks compared with the baseline. The 16S rRNA sequencing revealed an increase in bacterial diversity and beneficial bacteria in the Firmicutes phylum, Bacilli class, and a reduction in the mutans streptococci group in the probiotic group. The opposite results were found in the control group. This study did not find any caries increment, nor did the subjects have any side effects after product consumption.

CONCLUSION

With the limitation of a short-time study in low caries children, it showed that L. rhamnosus SD11 could increase beneficial bacteria in the Firmicutes phylum and Bacilli class that might support good oral health in children.

Probiotics mixture and taurine attenuate L-arginine-induced acute pancreatitis in rats: Impact on transient receptor potential vanilloid-1 (TRPV-1)/IL-33/NF-κB signaling and apoptosis

Acute pancreatitis (AP) is an inflammatory disorder of acinar cells. It may develop into severe chronic pancreatitis with a significant mortality rate. The current study aimed to assess the therapeutic effect of a Lactobacillus (LAB) mixture against rat AP. Six groups were created including control, taurine (300 mg/kg; i.p.) for 7 days, LAB mixture for 7 days, L-arginine (2.5 g/kg; i.p.) 2 doses with 1 h interval on 1st day, L-arginine+taurine, and L-arginine+LAB. Serum amylase and lipase activities were measured. Pancreatic tissue was used for histopathological examination, oxidative stress biomarkers including malondialdehyde (MDA) and reduced glutathione (GSH), and inflammatory biomarkers including myeloperoxidase (MPO) and interleukin (IL)-33 assessment. qRT-PCR was used for transient receptor potential vanilloid-1 (TRPV-1) investigation and Western blot analysis for measuring nuclear factor kappa-B (NF-κBp65) and the apoptosis biomarker; caspase-3. Taurine and LAB reduced lipase and significantly ameliorated induced oxidative stress by normalizing MDA and GSH contents. They counteracted inflammation by reducing MPO, IL-33, NF-κBp65, and TRPV-1. In addition, taurine and LAB counteracted apoptosis as proved by reduced caspase-3 expression. Taken together, these findings indicate that taurine and the use LAB mixture can mitigate AP by L-arginine via influencing TRPV-1/IL-33/NF-κB signaling together with exhibiting potent antioxidant and anti-inflammatory effects.

Photoprotection Against UV-Induced Skin Damage Using Hyaluronic Acid Produced by Lactiplantibacillus plantarum and Enterococcus durans

Exposure to ultraviolet (UV) radiation is one of the major factors that causes skin aging, erythema, sunburns, and skin cancer. This study aimed to select probiotic bacterial isolates able to produce high yield of hyaluronic acid (HA) to be employed for skin photoprotection and other possible biological applications. The selected isolates K11 and St3 were able to produce the highest yields of HA 4.8 and 4.4 mg/ml, respectively. Both isolates were identified as Enterococcus durans strain K11 and Lactiplantibacillus plantarum strain St3 using 16S rRNA gene sequencing. The antioxidant activity of HA produced by E. durans strain K11 and L. plantarum strain St3 was (65.4 0.2%) and (66.6 0.1%), respectively. The viability of UVB-irradiated keratinocytes pre-treated with HA produced by E. durans strain K11 and L. plantarum strain St3 was 91.3 and 91.4%, respectively, compared with the control. While the viability of UVB-irradiated keratinocytes post-treated with HA produced by E. durans strain K11 and L. plantarum strain St3 was 86 and 88.5%, respectively. To the best of our knowledge, this is the first recordation of HA production by Enterococcus durans and Lactiplantibacillus plantarum which revealed a significant radioprotection of the human keratinocytes against UVB radiation.

The Influence of Gut Microbiota on Oxidative Stress and the Immune System

The human gastrointestinal tract is home to a complex microbial community that plays an important role in the general well-being of the entire organism. The gut microbiota generates a variety of metabolites and thereby regulates many biological processes, such as the regulation of the immune system. In the gut, bacteria are in direct contact with the host. The major challenge here is to prevent unwanted inflammatory reactions on one hand and on the other hand to ensure that the immune system can be activated when pathogens invade. Here the REDOX equilibrium is of utmost importance. This REDOX equilibrium is controlled by the microbiota either directly or indirectly via bacterial-derived metabolites. A balanced microbiome sorts for a stable REDOX balance, whereas dysbiosis destabilizes this equilibrium. An imbalanced REDOX status directly affects the immune system by disrupting intracellular signaling and promoting inflammatory responses. Here we (i) focus on the most common reactive oxygen species (ROS) and (ii) define the transition from a balanced REDOX state to oxidative stress. Further, we (iii) describe the role of ROS in regulating the immune system and inflammatory responses. Thereafter, we (iv) examine the influence of microbiota on REDOX homeostasis and how shifts in pro- and anti-oxidative cellular conditions can suppress or promote immune responses or inflammation.

Antidiabetic Activity of Potential Probiotics Limosilactobacillus spp., Levilactobacillus spp., and Lacticaseibacillus spp. Isolated from Fermented Sugarcane Juice: A Comprehensive In Vitro and In Silico Study

Probiotics are regarded as a potential source of functional foods for improving the microbiota in human gut. When consumed, these bacteria can control the metabolism of biomolecules, which has numerous positive effects on health. Our objective was to identify a probiotic putative Lactobacillus spp. from fermented sugarcane juice that can prevent α-glucosidase and α-amylase from hydrolyzing carbohydrates. Isolates from fermented sugarcane juice were subjected to biochemical, molecular characterization (16S rRNA) and assessed for probiotic traits. Cell-free supernatant (CS) and extract (CE) and also intact cells (IC) were examined for the inhibitory effect on α-glucosidase and α-amylase. CS of the strain showed the highest inhibition and was subjected to a liquid chromatography-mass spectrometry (LCMS) analysis to determine the organic acid profile. The in silico approach was employed to assess organic acid stability and comprehend enzyme inhibitors' impact. Nine isolates were retained for further investigation based on the preliminary biochemical evaluation. Limosilactobacillus spp., Levilactobacillus spp., and Lacticaseibacillus spp. were identified based on similarity > 95% in homology search (NCBI database). The strains had a higher survival rate (>98%) than gastric and intestinal fluids, also a high capacity for adhesion (hydrophobicity > 56%; aggregation > 80%; HT-29 cells > 54%; buccal epithelial cells > 54%). The hemolytic assay indicated that the isolates could be considered safe. The isolates' derivatives inhibited enzymes to varying degrees, with α-glucosidase inhibition ranging from 21 to 85% and α-amylase inhibition from 18 to 75%, respectively. The CS of RAMULAB54 was profiled for organic acid that showed the abundance of hydroxycitric acid, citric acid, and lactic acid indicating their role in the observed inhibitory effects. The in silico approach has led us to understand that hydroxycitric acid has the ability to inhibit both the enzymes (α-glucosidase and α-amylase) effectively. Inhibiting these enzymes helps moderate postprandial hyperglycemia and regulates blood glucose levels. Due to their promising antidiabetic potential, these isolates can be used to enhance intestinal health.

Isolation, identification, and biochemical characterization of five Lacticaseibacillus strains from Oggtt: A traditional fermented and dried buttermilk

This study investigates the isolation and characterization of the main lactic acid bacteria responsible for fermentation of Oggtt, a dried fermented buttermilk. Five isolates with Gram-positive staining and negative catalase and oxidase activity were identified using phenotypic and genotypic methods, and their antagonistic, exopolysaccharides and organic acid production, proteolytic activity, and antioxidant capacity were assessed. The isolates are classified as Lacticaseibacillus paracasei Ogt_1, Lacticaseibacillus casei Ogt_2, Lacticaseibacillus paracasei Ogt_3, Lacticaseibacillus paracasei Ogt_4, and Lacticaseibacillus paracasei Ogt_5. All strains possessed high antagonistic activity against Proteus vulgaris, Staphylococcus aureus, and Escherichia coli. All strains produced high levels of lactic acid (11177.3-15404.9 μg/ml), tartaric acid (2197.8-4058.5 μg/ml), and exopolysaccharides(20.86-239.9 mg/L) and possessed high proteolytic and antioxidant activity at variable manners. Overall, this study indicates the isolation of important Lacticaseibacillus strains from Oggtt, which could be used as starter cultures for developing functional foods.

Antimutagenic Activity as a Criterion of Potential Probiotic Properties

The antimutagenic activity of probiotic strains has been reported over several decades of studying the effects of probiotics. However, this activity is rarely considered an important criterion when choosing strains to produce probiotic preparations and functional food. Meanwhile, the association of antimutagenic activity with the prevention of oncological diseases, as well as with a decrease in the spread of resistant forms in the microbiota, indicates its importance for the selection of probiotics. Besides, an antimutagenic activity can be associated with probiotics' broader systemic effects, such as geroprotective activity. The main mechanisms of such effects are considered to be the binding of mutagens, the transformation of mutagens, and inhibition of the transformation of promutagens into antimutagens. Besides, we should consider the possibility of interaction of the microbiota with regulatory processes in eukaryotic cells, in particular, through the effect on mitochondria. This work aims to systematize data on the antimutagenic activity of probiotics and emphasize antimutagenic activity as a significant criterion for the selection of probiotic strains.

Synbiotics and Their Antioxidant Properties, Mechanisms, and Benefits on Human and Animal Health: A Narrative Review

Antioxidants are often associated with a variety of anti-aging compounds that can ensure human and animal health longevity. Foods and diet supplements from animals and plants are the common exogenous sources of antioxidants. However, microbial-based products, including probiotics and their derivatives, have been recognized for their antioxidant properties through numerous studies and clinical trials. While the number of publications on probiotic antioxidant capacities and action mechanisms is expanding, that of synbiotics combining probiotics with prebiotics is still emerging. Here, the antioxidant metabolites and properties of synbiotics, their modes of action, and their different effects on human and animal health are reviewed and discussed. Synbiotics can generate almost unlimited possibilities of antioxidant compounds, which may have superior performance compared to those of their components through additive or complementary effects, and especially by synergistic actions. Either combined with antioxidant prebiotics or not, probiotics can convert these substrates to generate antioxidant compounds with superior activities. Such synbiotic-based new routes for supplying natural antioxidants appear relevant and promising in human and animal health prevention and treatment. A better understanding of various component interactions within synbiotics is key to generating a higher quality, quantity, and bioavailability of antioxidants from these biotic sources.

Antioxidative properties analysis of gastrointestinal lactic acid bacteria in Hainan black goat and its effect on the aerobic stability of total mixed ration

In this study, lactic acid bacteria strains (HCS-01, HCS-05, HCS-07, HCW-08, and HCW-09) derived from the gastrointestinal tract of Hainan black goat were evaluated for their antioxidant capacity in vitro, and the lactic acid bacteria with strong antioxidant capacity were screened for application to improve the aerobic stability of total mixed ration (TMR). The results showed that all the tested lactic acid bacteria had a certain tolerance to hydrogen peroxide. By comprehensively comparing the scavenging abilities of fermentation supernatants, whole cell bacterial suspensions and cell contents of five lactic acid bacteria strains to 2,2-diphenyl-1-picrylhydrazine (DPPH), hydroxyl radicals and superoxide anions, and their antioxidant enzyme activity, it was found that Lactobacillus fermentum HCS-05 and Lactobacillus plantarum HCW-08 have the strongest comprehensive antioxidant capacity, and their scavenging capacity for various free radicals has reached more than 60%. Using strains HCS-05, HCW-08 and laboratory-preserved Lactobacillus plantarum HDX1 fermented TMR, the fermentation quality and aerobic stability of the feed after 60 days of fermentation were significantly higher than those of the blank treatment group. The effect of mixed strains HCS-05 and HCS-08 for TMR fermentation was the best (P &lt; 0.05). At the same time, the fermentation effect of Lactobacillus plantarum HDX1 on TMR was significantly lower than that of the selected lactic acid bacteria from the gastrointestinal tract of Hainan black goats (P &lt; 0.05). The results show that the test strain can significantly improve the aerobic stability of the fermented feeds.

Commensal Lactobacilli Enhance Sperm Qualitative Parameters in Dogs

Although several methods have been developed to improve male fertility and sperm quality, subfertility remains a primary clinical issue in male reproduction worldwide. The aim of this study was to determine the effects of the oral administration of three commensal Lactobacillus spp. on healthy normozoospermic dogs and the qualitative parameters of their sperm. Three weeks of supplementation induced a significant decrease of two phyla, Proteobacteria and Tenericutes, and an increase of phylum Firmicutes. At the species level, the number of Fusobacterium perfoetens and Anaerobiospirillum succiniciproducens decreased, while Limosilactobacillus reuteri increased. Parallel to these results, qualitative sperm parameters such as total and progressive motility, acrosome integrity, and other kinematic parameters were significantly enhanced after commensal lactobacilli supplementation. In addition, we showed that Firmicutes were positively correlated with sperm qualitative parameters, while Proteobacteria, F. perfoetens, and A. succiniciproducens were negatively correlated. Considering the similarities between the gut microbiome of dogs and humans, these results provide more insight into how gut microbiota regulation could improve male sperm quality in both species.

Lactobacillus salivarius CML352 Isolated from Chinese Local Breed Chicken Modulates the Gut Microbiota and Improves Intestinal Health and Egg Quality in Late-Phase Laying Hens

Lactobacillus strains with fine probiotic properties are continuously needed in the laying hen industry to improve the animals’ gut health and production performance. In this study, we isolated 57 Lactobacillus strains from the gut microbiota of 17 different chicken breeds in China. We characterized the probiotic features of these isolates, and evaluated the effects of a selected strain, Lactobacillus salivarius CML352, on the production performance and gut health of the late-phase laying hens. The results showed that the isolates varied much in probiotic properties, among which L. salivarius CML352 displayed high acid and bile salt tolerance, high hydrophobicity, auto-aggregation, and antibacterial activities. Whole genome sequencing analysis showed that CML352 was closely related to a strain isolated from human fecal samples, but had different functional potentials. Dietary supplementary of L. salivarius CML352 significantly reduced the Firmicutes to Bacteroidetes ratio, increased the expression of Muc-2, and decreased the expression of MyD88, IFN-γ, and TLR-4. Furthermore, strain CML352 reduced the birds’ abdominal fat deposition, and improved egg quality. Taken together, this study indicated that the newly isolated L. salivarius strain might be a worthy probiotic with positive impacts on the intestinal health and production performance of late-phase laying hens.

The Therapeutic Role of Exercise and Probiotics in Stressful Brain Conditions

Oxidative stress has been recognized as a contributing factor in aging and in the progression of multiple neurological disorders such as Parkinson’s disease, Alzheimer’s dementia, ischemic stroke, and head and spinal cord injury. The increased production of reactive oxygen species (ROS) has been associated with mitochondrial dysfunction, altered metal homeostasis, and compromised brain antioxidant defence. All these changes have been reported to directly affect synaptic activity and neurotransmission in neurons, leading to cognitive dysfunction. In this context two non-invasive strategies could be employed in an attempt to improve the aforementioned stressful brain status. In this regard, it has been shown that exercise could increase the resistance against oxidative stress, thus providing enhanced neuroprotection. Indeed, there is evidence suggesting that regular physical exercise diminishes BBB permeability as it reinforces antioxidative capacity, reduces oxidative stress, and has anti-inflammatory effects. However, the differential effects of different types of exercise (aerobic exhausted exercise, anaerobic exercise, or the combination of both types) and the duration of physical activity will be also addressed in this review as likely determinants of therapeutic efficacy. The second proposed strategy is related to the use of probiotics, which can also reduce some biomarkers of oxidative stress and inflammatory cytokines, although their underlying mechanisms of action remain unclear. Moreover, various probiotics produce neuroactive molecules that directly or indirectly impact signalling in the brain. In this review, we will discuss how physical activity can be incorporated as a component of therapeutic strategies in oxidative stress-based neurological disorders along with the augmentation of probiotics intake.

Novel Millet-Based Flavored Yogurt Enriched With Superoxide Dismutase

Superoxide dismutase (SOD) is an important antioxidant enzyme with different physiological functions, which can be used as a nutritional fortifier in food. Cereal-based fermented products are becoming popular worldwide. In this study, novel millet-based flavored yogurt enriched with SOD was developed. Lactiplantibacillus plantarum subsp. plantarum was screened, which manufactured SOD activity of 2476.21 ± 1.52 U g^-1. The SOD content of millet yogurt was 19.827 ± 0.323 U mL^-1, which was 63.01, 50.11, and 146.79% higher than that of Bright Dairy Yogurt 1911, Junlebao and Nanjing Weigang, respectively. Fifty-four volatile flavor substances and 22,571 non-volatile flavor substances were found in yogurt. Compared to traditional fermented yogurt, 37 non-volatile metabolites in yogurt with millet enzymatic fermentation broth were significantly upregulated, including 2-phenyl ethanol, hesperidin, N-acetylornithine and L-methionine, which were upregulated by 3169.6, 228.36, 271.22, and 55.67 times, respectively, thereby enriching the sensory and nutritional value of yogurt. Moreover, the manufacture of unpleasant volatile flavor substances was masked, making the product more compatible with consumers' tastes.

An Update on the Effectiveness of Probiotics in the Prevention and Treatment of Cancer

Probiotics are living microbes that play a significant role in protecting the host in various ways. Gut microbiota is one of the key players in maintaining homeostasis. Cancer is considered one of the most significant causes of death worldwide. Although cancer treatment has received much attention in recent years, the number of people suffering from neoplastic syndrome continues to increase. Despite notable improvements in the field of cancer therapy, tackling cancer has been challenging due to the multiple properties of cancer cells and their ability to evade the immune system. Probiotics alter the immunological and cellular responses by enhancing the epithelial barrier and stimulating the production of anti-inflammatory, antioxidant, and anticarcinogenic compounds, thereby reducing cancer burden and growth. The present review focuses on the various mechanisms underlying the role of probiotics in the prevention and treatment of cancer.

Probiotic Fermented Beverage From Macroalgae

We have tested the hypothesis that a fermented beverage from the macroalgae Hydropuntia eucheumatoides exhibits antioxidant and enzymatic activity. The macroalga was hydrolyzed (maximum hydrolysis yield: 78%) with a mixture of the enzymes viscozyme and lactozyme. Then, the hydrolyzate was fermented with Lactobacillus casei and Saccharomyces boulardii. This beverage contained oligosaccharide prebiotics. The lactic acid, acetic acid, ethanol, methanol, cell count, pH, and heavy metal content of the beverage were determined. All tested heavy metals were either not detected (eg, As) or within the US Food and Drug Administration limits (eg, Fe).

Flavonoid-Rich Extract of Paeonia lactiflora Petals Alleviate d-Galactose-Induced Oxidative Stress and Restore Gut Microbiota in ICR Mice

This study was aimed to investigate the antioxidant effect of Paeonia lactiflora Pall. petal flavonoids extract (PPF) on d-galactose (d-gal)-induced ICR mice. In this study, sixty male ICR mice were randomly divided into six groups during an 8 weeks experimental period, including normal control (NC) group, d-gal group, epigallocatechin gallate (EGCG) group, low, medium, and high dose PPF groups (10, 20 and 40 mg/kg/day). The results showed that intragastric administration with PPF significantly reverses the atrophy of the visceral organs of oxidative damage mice in a dose-dependent relationship. PPF indicated the antioxidant capacity to decrease the malondialdehyde (MDA) level and improve the activity of superoxide dismutase (SOD), catalase (CAT) as well as glutathione peroxidase (GSH-Px). In addition, PPF treatment reversed gut microbiota dysbiosis by increasing the relative abundance of Lactobacillaceae. Spearman correlation analysis showed that the body's oxidative stress markers were directly related to changes in gut microbiota. These findings reveal firstly that PPF could alleviate d-Gal-induced oxidative stress and modulate gut microbiota balance.

Antibacterial and antiplaque efficacy of a lactoperoxidase-thiocyanate-hydrogen-peroxide-system-containing lozenge

Background

Antimicrobial agents are considered valuable adjuncts to mechanical methods of plaque control. However, their long-term use can be limited because of side effects.

Therefore, using physiological substances is promising due to no risk of development, for example, of microbial resistances, allergies or DNA damaging. The lactoperoxidase-thiocyanate-hydrogen peroxide system (LPO-system) is a highly effective antimicrobial system. This study aimed to evaluate in a randomized study with a four-replicate cross-over design the effectiveness of two oral hygiene lozenges containing LPO-system in oral hygiene.

Results

After using the mouth rinse as positive control (A) and allocated test lozenges (B) (0.083% H₂O₂) & (C) (0.04% H₂O₂) for 4 days instead of the normal oral hygiene procedures (tooth brushing etc.), Listerine rinse (A) was statistically significantly more effective than the LPO-system-lozenge with 0.083% H₂O₂, the LPO-system-lozenge with 0.04% H₂O₂, and the placebo lozenge (D) in inhibiting plaque. Lozenges B and C were statistically significantly more effective than the placebo lozenge, but no statistically significant differences could be observed between them.

The LPO-system-lozenge (B) reduced statistically significantly more S. mutans than the LPO-system-lozenge with (C) and the placebo lozenge (D). The LPO-system-lozenge (C) reduced statistically significantly more Lactobacilli than Listerine (A), the LPO-system-lozenge (B) and the placebo lozenge (D). There were no statistically significant differences in the total CFUs between Listerine rinse, the LPO-system-lozenge with 0.083% H₂O₂ (B), the LPO-system-lozenge with 0.04% H₂O₂ (C), and the placebo lozenge (D). On day 5 there were no differences of the OSCN⁻-values between all A, B, C, and D. However, the SCN⁻-values increased over the days in both LPO-system-lozenges (B/C). The statistically significant differences between B/C and A/D on day 5 were as followed: A to B p = 0.0268; A to C p = 0.0035; B to D p = 0.0051; C to D p = 0.0007. Only in the group of Listerine (A) increased the NO₃⁻/NO₂⁻-quotient over the test time, which indicates a reduction of nitrate-reducing bacteria. On Day 5 the statistically significant difference between A and B was p = 0.0123.

Conclusions

The results indicate that lozenges containing a complete LPO-system, inhibiting plaque regrowth and reducing cariogenic bacteria, may be used in the daily oral hygiene.

Lactobacillus fermentum and Lactobacillus crispatus Do Not Have Cytotoxic Effects on HN5 Oral Squamous Cell Carcinoma Cell Line

Background

The oral environment has a very complex normal flora and a wide variety of bacteria including lactobacilli. Studies have shown oral microbial flora has important influence in the development of oral cancer. Squamous cell carcinomas account for more than 90% of cancers in oral cavity. Lactobacilli are known as one of the newest methods for the prevention and treatment of cancers. Previous studies on the effects of probiotics on oral cancer cells are very limited, and only two species of Lactobacillus which are not present in the normal oral microflora have been studied. Due to the unknown effects of lactobacilli on oral cancer, this study aimed to investigate the effect of two species of lactobacilli of oral cavity on oral cancer cells.

Methods and Materials

The effects of the supernatant of two lactobacilli, namely, fermentum and crispatus were studied on HN5-cancer cells. The MTT method was used to study the effects of lactobacilli on inhibition of cancer cell growth.

Results

The results showed that these lactobacilli do not prevent the progression of oral cancer cells. Moreover, the results showed that the acidic medium had the most effect on reducing the growth of oral cancer cells.

Conclusion

Due to the different effects of lactobacilli on various cancer types, the effects of two Lactobacillus crispatus and Lactobacillus fermentum on other oral cancer cell lines may be different from what has been reported in this study.

Fermented milk containing a potential probiotic Lactobacillus rhamnosus SD11 with maltitol reduces Streptococcus mutans: A double-blind, randomized, controlled study

Background/purpose

Sucrose has been considered as a cariogenic substrate due to large amounts of acid production after fermentation by certain oral bacteria, thus sugar alcohols are often used to replace sucrose. The aims of this study were to investigate the effect of maltitol on the growth and acid production of Streptococcus mutans and Lactobacillus rhamnosus-SD11 compared to various sugars, and to examine whether the fermented milk containing a potential probiotic L. rhamnosus-SD11 with maltitol could reduce S. mutans.

Materials and methods

The acid production of tested sugars by cariogenic S. mutans was measured using pH meter. In a clinical trial, 123 children were recruited and randomly assigned to either the probiotic- or control-fermented milk, once daily for 4 weeks. The target bacteria levels in the saliva were examined using a real-time PCR at baseline, 4 and 8 weeks. The oral examination was recorded at the baseline and 8 weeks.

Results

The results showed that maltitol exhibited less acid production than simple sugars. In the clinical trial, a significant reduction of salivary total streptococci and S. mutans occurred, while the levels of salivary lactobacilli significantly increased in the probiotic group compared to the control group after receiving the probiotic fermented milk.

Conclusion

The daily consumption of the fermented milk containing L. rhamnosus-SD11 with maltitol had beneficial effects on oral health by reducing salivary S. mutans. Thus, the substitution of simple sugars by maltitol in dairy products containing L. rhamnosus-SD11 may be an alternative way to prevent the risk of caries.

Diabetes mellitus and congestive heart failure: the prevalence of congestive heart failure in patients with and without diabetes in Poland

INTRODUCTION

Diabetes mellitus is a systemic disease and has a negative effect on the cardiovascular system. This paper aimed to present a retrospective analysis of morbidity associated with heart failure in subgroups of patients with and without diabetes in Poland in 2012.

MATERIAL AND METHODS

Data from the National Health Fund were used for the study. In general, 656,937 patients with heart failure, including 281,538 males and 375,354 females, were studied. In this population, additionally, 201,043 patients with heart failure (main diagnosis) and diabetes were studied, including 82,117 males and 118,926 females.

RESULTS

The mean index of morbidity associated with heart failure in the whole subpopulation of diabetes patients was 9.03%; 8.42% for males and 9.50% for females. Morbidity associated with heart failure in the population of patients diagnosed with diabetes in Poland in 2012 was seven times higher compared to morbidity associated with heart failure in non-diabetes patients. Morbidity associated with heart failure in females was significantly higher compared to morbidity in males in the whole population, in both the subpopulations of patients with and without diabetes.

CONCLUSIONS

Diabetes mellitus significantly increases risk of heart failure in both women and men. The risk is significantly high after the age of 60 years and higher in females.

Food-borne Lactiplantibacillus plantarum protect normal intestinal cells against inflammation by modulating reactive oxygen species and IL-23/IL-17 axis

Food-associated Lactiplantibacillus plantarum (Lpb. plantarum) strains, previously classified as Lactobacillus plantarum, are a promising strategy to face intestinal inflammatory diseases. Our study was aimed at clarifying the protective role of food-borne Lpb. plantarum against inflammatory damage by testing the scavenging microbial ability both in selected strains and in co-incubation with normal mucosa intestinal cells (NCM460). Here, we show that Lpb. plantarum endure high levels of induced oxidative stress through partially neutralizing reactive oxygen species (ROS), whereas they elicit their production when co-cultured with NCM460. Moreover, pre-treatment with food-borne Lpb. plantarum significantly reduce pro-inflammatory cytokines IL-17F and IL-23 levels in inflamed NCM460 cells. Our results suggest that food-vehicled Lpb. plantarum strains might reduce inflammatory response in intestinal cells by directly modulating local ROS production and by triggering the IL-23/IL-17 axis with future perspectives on health benefits in the gut derived by the consumption of functional foods enriched with selected strains.

Fermented blueberry pomace ameliorates intestinal barrier function through the NF-κB-MLCK signaling pathway in high-fat diet mice

The barrier-improving functions of fermented blueberry pomace (FBP) and its potential mechanism were investigated in this study. Polyphenols and the approximate composition of FBP were evaluated according to the National Standard of the People's Republic of China and the UPLC-MS system. Male C57BL/6 mice were fed a control diet (CD) or a high-fat diet (HFD) with or without FBP supplementation. Oxidative stress, inflammation, histological morphology and the expression of functional proteins in the small intestine of mice were evaluated using the enzyme linked immunosorbent assay (ELISA), quantitative polymerase chain reaction (qPCR) and western blotting. The content of protein, fat, soluble dietary fiber, insoluble dietary fiber and carbohydrates (non-dietary fiber) was 114.5 ± 1.5 g kg^-1, 5.0 ± 0.2 g kg^-1, 48.0 ± 0.1 g kg^-1, 360.3 ± 2.2 g kg^-1 and 423 g kg^-1 (by difference), respectively. Thirty-six polyphenols were identified in FBP. FBP improved the growth of mice and attenuated hepatic and intestinal oxidative stress. Intestinal inflammation was significantly reduced through the decrease of tumor necrosis factor-alpha (TNF-α) and myeloperoxidase (MPO) as well as an increase of interleukin-10 (IL-10). FBP supplementation significantly improved the intestinal morphology and barrier function, potentially by mediating the NF-κB-MLCK signaling pathway. The supplementation of FBP in HFD mice enhanced the intestinal barrier function. This suggested that polyphenol-rich by-products might provide a similar health effect in HFD individuals.

Reduction of Streptococcus mutans by probiotic milk: a multicenter randomized controlled trial

OBJECTIVE

To investigate the effects of probiotics, Lactobacillus paracasei SD1, on the quantities of Streptococcus mutans in saliva and plaque samples of preschool children.

DESIGN

This randomized trial recruited 487 preschool children from eight childcare centers. Participants were assigned to receive a 6-month course of placebo milk daily (group I), probiotic milk either daily (group II) or three days a week (triweekly, group III). The absolute quantities of S. mutans and total lactobacilli in the saliva and plaque samples at baseline (T0), after intervention (T6), and 6 months after discontinuation (T12) were assessed by qPCR.

RESULTS

Of 487 children, 354 completed all follow-up periods. However, only 268 children (3.2 ± 0.8 years old; groups I = 86, II = 89, and III = 93) provided adequate saliva for qPCR. Whereas the quantities of S. mutans were significantly decreased in groups II and III compared to group I in the saliva and plaque samples at T6 and T12, those of total lactobacilli were significantly increased (p < 0.0167). There was no difference in the quantities of S. mutans or total lactobacilli between groups II and III at any period. Significant changes in the quantities of S. mutans and total lactobacilli lasted until T12 compared to T0 (p < 0.0167).

CONCLUSIONS

Probiotic administration daily or triweekly reduces S. mutans quantities, whereas it increases total lactobacilli quantities that persists at least 6 months after discontinuation in the saliva and plaque samples of preschool children.

CLINICAL RELEVANCE

Daily or triweekly consumption of L. paracasei SD1 supplemented in milk may help prevent dental caries in preschool children.

New crosstalk between probiotics Lactobacillus plantarum and Bacillus subtilis

It was reported that oral administration of Bacillus favored the growth of Lactobacillus in the intestinal tract. Here, this phenomenon was confirmed by co-cultivation of Bacillus subtilis 168 and Lactobacillus plantarum SDMCC050204-pL157 in vitro. To explain the possible molecular mechanisms, B. subtilis 168 cells were incubated in simulated intestinal fluid at 37 °C for 24 h, and up to 90% of cells autolysed in the presence of bile salts. Addition of the autolysate to medium inoculated with Lb. plantarum SDMCC050204 decreased the concentration of H₂O₂ in the culture, alleviated DNA damage and increased the survival of Lb. plantarum, as like the results of exogenous heme addition. These results suggested that the autolysate provided heme, which activated the heme-dependent catalase KatA in Lb. plantarum SDMCC050204. HPLC confirmed the presence of heme in the autolysate. Disruption of the Lb. plantarum SDMCC050204 katA gene abolished the protective effect of the B. subtilis 168 autolysate against H₂O₂ stress. We thus hypothesized that the beneficial effect of Bacillus toward Lactobacillus was established through activation of the heme-dependent catalase and remission of the damage of reactive oxygen species against Lactobacillus. This study raised new crosstalk between the two frequently-used probiotics, highlighting heme-dependent catalase as the key mediator.

NADPH oxidases and ROS signaling in the gastrointestinal tract

Reactive oxygen species (ROS), initially categorized as toxic by-products of aerobic metabolism, have often been called a double-edged sword. ROS are considered indispensable when host defense and redox signaling is concerned and a threat in inflammatory or degenerative diseases. This generalization does not take in account the diversity of oxygen metabolites being generated, their physicochemical characteristics and their production by distinct enzymes in space and time. NOX/DUOX NADPH oxidases are the only enzymes solely dedicated to ROS production and the prime ROS producer for intracellular and intercellular communication due to their widespread expression and intricate regulation. Here we discuss new insights of how NADPH oxidases act via ROS as multifaceted regulators of the intestinal barrier in homeostasis, infectious disease and intestinal inflammation. A closer look at monogenic VEOIBD and commensals as ROS source supports the view of H₂O₂ as key beneficial messenger in the barrier ecosystem.

iNOS- and NOX1-dependent ROS production maintains bacterial homeostasis in the ileum of mice

The intestinal epithelial cells constitute the first line of defense against gut microbes, which includes secretion of various antimicrobial substances. Reactive oxygen species (ROS) are well characterized as part of the innate phagocytic immunity; however, a role in controlling microorganisms in the gut lumen is less clear. Here, we show a role for nitric oxide synthase (iNOS)- and NOX1-produced ROS in maintaining homeostasis of the gut microbiota. In vivo imaging revealed distinctly high levels of ROS in the ileum of normal healthy mice, regulated in accordance with the amount of gut bacteria. The ROS level was dependent on the nitric oxide and superoxide producers iNOS and NOX1, respectively, suggesting peroxynitrite as the effector molecule. In the ileum of iNOS- and NOX1-deficient mice, the bacterial load is increased and the composition is more cecum like. Our data suggest a unique role of ileum in maintaining homeostasis of gut microbes through production of ROS with potential importance for preventing reflux from the large intestine, bacterial overgrowth, and translocation.