Invited review: the scientific basis of Lactobacillus acidophilus NCFM functionality as a probiotic

Efficacy of probiotic supplements in improving the symptoms of psychosis, anxiety, insomnia, and anorexia due to amphetamine and methamphetamine use: a randomized clinical trial

RATIONALE

Changes in the density and diversity of gut microbiota in chronic use of methamphetamine have been mentioned as contributors to psychotic and anxiety symptoms, sleep problems, and loss of appetite.

OBJECTIVE

In this placebo-controlled clinical trial, we investigated the effect of the probiotic Lactobacillus Acidophilus in improving psychiatric symptoms among hospitalized patients with chronic methamphetamine use along with psychotic symptoms.

METHODS

60 inpatients with a history of more than 3 years of methamphetamine use, were randomly assigned to one of two groups receiving either a probiotic capsule or placebo along with risperidone for 8 weeks based on a simple randomization method. In weeks 0, 4, and 8, patients were evaluated using the Brief Psychiatric Rating Scale (BPRS), Beck Anxiety Inventory (BAI), Pittsburgh Sleep Quality Index (PSQI), Simple Appetite Nutritional Questionnaire (SANQ), and Body Mass Index (BMI).

RESULTS

Compared to the control group, patients receiving probiotics had better sleep quality, greater appetite, and higher body mass index (there were significant interaction effects of group and time at Week 8 in these variables (t = -3.32, B = -1.83, p = .001, d = 0.89), (t = 10.50, B = 2.65, p <.001, d = 1.25) and (t = 3.40, B = 0.76, p <.001, d = 0.30), respectively. In terms of the improvement of psychotic and anxiety symptoms, there was no statistically significant difference between the two groups.

CONCLUSIONS

The use of probiotics was associated with improved sleep quality, increased appetite, and increased body mass index in patients with chronic methamphetamine use. Conducting more definitive clinical trials with larger sample sizes and longer-term follow-up of cases is recommended.

Human-gut bacterial protein-protein interactions: understudied but impactful to human health

The human gut microbiome is associated with a wide range of diseases; yet, the mechanisms these microbes use to influence human health are not fully understood. Protein-protein interactions (PPIs) are increasingly identified as a potential mechanism by which gut microbiota influence their human hosts. Similar to some PPIs observed in pathogens, many disease-relevant human-gut bacterial PPIs function by interacting with components of the immune system or the gut barrier. Here, we highlight recent advances in these two areas. It is our opinion that there is a vastly unexplored network of human-gut bacterial PPIs that contribute to the prevention or pathogenesis of various diseases and that future research is warranted to expand PPI discovery.

Isolation and in vitro assessment of chicken gut microbes for probiotic potential

Poultry production occupies an important place in the economy of any country. High broiler production in recent years has badly affected its profitability due to bad feed quality, excessive use of chemotherapeutic agents, emergence of diverse pathogens, and the deficiencies in management practices during rearing cycle. Microbiological improvement of the meat quality using potential probiotics can be beneficial for broiler farming. Present study was initiated to isolate chicken gastrointestinal tract (GIT) bacteria with probiotic potential. To isolate probiotics from chicken gut, alimentary canal of chickens of known sizes and ages was suspended in ringers soln. Under shaking conditions for overnight followed by serial dilutions of ringers soln. Bacterial isolates were analyzed via growth curve analysis, biochemical testing using RapID™ NF Plus Panel kit, molecular characterization, antimicrobial activity assay, antibiotic sensitivity assay, GIT adherence assay, bile salt and gastric acid resistant assay, and cholesterol assimilation assay. Four bacteria isolated in present study were identified as Limosilactobacillus antri strain PUPro1, Lactobacillus delbrueckii strain PUPro2, Lacticaseibacillus casei strain PUPro3, and Ligilactobacillus salivarius strain PUPro4. L. delbrueckii strain PUPro2 grew extremely fast. All isolates exhibited exceptional resistance to increasing concentrations of NaCl and bile salts with value of p >0.5. L. delbrueckii strain PUPro2 adhered to chicken ileum epithelial cells and demonstrated the highest viable counts of 320 colony forming units (CFUs). Antagonistic action was found in all isolates against P. aeruginosa, B. subtilis, B. proteus, and S. aureus, with value of p >0.5. Antibiotic susceptibility testing showed sensitivity to all the antibiotics used. Cholesterol assimilation was detected in all bacteria, with values ranging from 216.12 to 192.2 mg/dL. All isolates exhibited γ-hemolysis. In future, these bacteria might be tested for their impact on broilers meat quality and growth and can be recommended for their use as supplements for broilers diet with positive impact on poultry production.

Applications of Proteomics in Probiotics Having Anticancer and Chemopreventive Properties

Proteomics has grown in importance in molecular sciences because it gives vital information on protein identification, expression levels, and alteration. Cancer is one of the world's major causes of death and is the major focus of much research. Cancer risk is determined by hereditary variables as well as the body's immunological condition. Probiotics have increasing medical importance due to their therapeutic influence on the human body in the prevention and treatment of numerous chronic illnesses, including cancer, with no adverse effects. Several anticancer, anti-inflammatory, and chemopreventive probiotics are studied using different proteomic approaches like two-dimensional gel electrophoresis, liquid chromatography-mass spectrometry, and matrix-assisted laser desorption/ionization mass spectrometry. To gain relevant information about probiotic characteristics, data from the proteomic analysis are evaluated and processed using bioinformatics pipelines. Proteomic studies showed the significance of different proteomic approaches in characterization, comparing strains, and determination of oxidative stress of different probiotics. Moreover, proteomic approaches identified different proteins that are involved in glucose metabolism and the formation of cell walls or cell membranes, and the differences in the expression of critical enzymes in the HIF-1 signaling pathway, starch, and sucrose metabolism, and other critical metabolic pathways.

Effects and Mechanisms of Resveratrol on the Adhesion of Lactobacillus acidophilus NCFM

Based on the adhesion and surface properties of Lactobacillus acidophilus NCFM, five common polyphenols in fruits and vegetables, including resveratrol, epicatechin, quercetin, hesperidin, and caffeic acid, were screened, and the reasons for resveratrol promoting adhesion were systematically explained. The results showed that resveratrol could significantly enhance NCFM adhesion to mucin (1.73 fold), followed by epicatechin (1.47 fold), caffeic acid (1.30 fold), and hesperidin (0.99 fold), while quercetin had a certain degree of inhibition (0.84 fold). The effects of these polyphenols on surface hydrophobicity and auto-aggregation of NCFM were consistent with adhesion results. Then, how resveratrol promotes NCFM adhesion was further explored. The results of the proteomic analysis showed that resveratrol changed the surface layer proteins of NCFM, involving 4 up-regulated proteins and 12 down-regulated proteins. In addition, resveratrol promoted the expression of mucin genes and the glycosylation of mucins on the HT-29 cell surface. Our results indicate that resveratrol changes the surface layer proteins of NCFM to modify surface properties and adhere to mucins. Meanwhile, resveratrol promotes expression and glycosylation of mucins in HT-29 cells. Our findings provide theoretical support for an in-depth explanation of the interaction among resveratrol, NCFM, and the HT-29 cells.

Lactobacillus acidophilus Expressing Murine Rotavirus VP8 and Mucosal Adjuvants Induce Virus-Specific Immune Responses

Rotavirus diarrhea-associated illness remains a major cause of global death in children under five, attributable in part to discrepancies in vaccine performance between high- and low-middle-income countries. Next-generation probiotic vaccines could help bridge this efficacy gap. We developed a novel recombinant Lactobacillus acidophilus (rLA) vaccine expressing rotavirus antigens of the VP8* domain from the rotavirus EDIM VP4 capsid protein along with the adjuvants FimH and FliC. The upp-based counterselective gene-replacement system was used to chromosomally integrate FimH, VP8Pep (10 amino acid epitope), and VP8-1 (206 amino acid protein) into the L. acidophilus genome, with FliC expressed from a plasmid. VP8 antigen and adjuvant expression were confirmed by flow cytometry and Western blot. Rotavirus naïve adult BALB/cJ mice were orally immunized followed by murine rotavirus strain ECWT viral challenge. Antirotavirus serum IgG and antigen-specific antibody-secreting cell responses were detected in rLA-vaccinated mice. A day after the oral rotavirus challenge, fecal antigen shedding was significantly decreased in the rLA group. These results indicate that novel rLA constructs expressing VP8 can be successfully constructed and used to generate modest homotypic protection from rotavirus challenge in an adult murine model, indicating the potential for a probiotic next-generation vaccine construct against human rotavirus.

Viability of Lactobacillus acidophilus in Thin-Film Freeze-Dried Powders Filled in Delayed-Release Vegetarian Capsules in a Simulated Gastric Fluid

Previously, we have shown that thin-film freeze-drying can be applied to prepare dry powders of bacteria such as Lactobacillus acidophilus. Herein, we tested the viability of L. acidophilus in thin-film freeze-dried powders (TFF powders) filled in delayed-release vegetarian capsules in a simulated gastric fluid (SGF) consisting of 0.1N hydrochloric acid and sodium chloride. Initially, we determined the water removal rate from frozen thin films on relatively larger scales (i.e., 10-750 g). We then prepared and characterized two TFF powders of L. acidophilus with either sucrose and maltodextrin or sucrose and hydroxypropyl methylcellulose acetate succinate (HPMC-AS), a pH-sensitive polymer, as excipients and evaluated the viability of the bacteria after the TFF powders were filled in delayed-release vegetarian capsules and the capsules were incubated in the SGF for 30 min. On 10-750 g scales and at the settings specified, water removal from frozen thin films was faster than from slow shelf-frozen bulk solids. When the L. acidophilus in sucrose and HPMC-AS TFF powder was filled into a delayed-release capsule that was placed into another delayed-release capsule, the bacterial viability reduction after incubation in the SGF can be minimized to within 1 log in colony forming unit (CFU). However, for the L. acidophilus in sucrose and maltodextrin TFF powder, even in the capsule-in-capsule dosage form, bacterial CFU reduction was > 2 logs. TFF powders of live microorganisms containing an acid-resistant material in capsule-in-capsule delayed-release vegetarian capsules have the potential for oral delivery of those microorganisms.

A critical review of the recent concept of artificial mechanical uterus design in relation to the maternal microbiome: An Update to past researches

The microbiome in the female reproductive tract plays an essential role in immune modulation and reproductive health. However, various microbes become established during pregnancy, the balance of which plays a crucial role in embryonic development and healthy births. The contribution of disturbances in the microbiome profile to embryo health is poorly understood. A better understanding of the relationship between reproductive outcomes and the vaginal microbiota is needed to optimize the chances of healthy births. In this regards, microbiome dysbiosis refers to conditions in which the pathways of communication and balance within the normal microbiome are imbalanced due to the intrusion of pathogenic microorganisms into the reproductive system. This review summarizes the current state of knowledge on the natural human microbiome, with a focus on the natural uterine microbiome, mother-to-child transmission, dysbiosis, and the pattern of microbial change in pregnancy and parturition, and reviews the effects of artificial uterus probiotics during pregnancy. These effects can be studied in the sterile environment of an artificial uterus, and microbes with potential probiotic activity can be studied as a possible therapeutic approach. The artificial uterus is a technological device or biobag used as an incubator, allowing extracorporeal pregnancy. Establishing beneficial microbial communities within the artificial womb using probiotic species could modulate the immune system of both the fetus and the mother. The artificial womb could be used to select the best strains of probiotic species to fight infection with specific pathogens. Questions about the interactions and stability of the most appropriate probiotics, as well as dosage and duration of treatment, need to be answered before probiotics can be a clinical treatment in human pregnancy.

Particulate Cell Wall Materials of Lactobacillus acidophilus as Vaccine Adjuvant

We evaluated Lactobacillus acidophilus (LA) for adjuvant application in animal vaccines. LA particles (LAPs) are made by treating LA with purification processes and high-pressure homogenization (HPH). We found that LAPs treated with HPH with trehalose and emulsifiers had an average particle size of 179 nm, considerably smaller than LAPs without additives. First, we evaluated the adjuvanticity of LAPs using a murine model with ovalbumin antigens, revealing that LAPs, especially in a five-fold concentration, could induce a considerable antibody response compared with other current adjuvants. In poultry vaccination tests using inactivated Newcastle disease virus, LAPs alone could induce a similar antibody response compared to commercial water-in-oil (W/O) adjuvant ISA70, a commercial adjuvant, at weeks 4 and 6; however, they declined faster than ISA70 at weeks 8 and 10. LAPs added to conventional adjuvant materials, such as mineral oil-based O/W emulsions, showed similar adjuvanticity to ISA70. LA-H5-C, composed of carbomer, emulsifiers and trehalose showed no significant body weight change in acute toxicity compared to other adjuvants including ISA70, making formulated LAPs a potential candidate for use as a veterinary vaccine adjuvant.

Effect of Acylated and Nonacylated Anthocyanins on Urine Metabolic Profile during the Development of Type 2 Diabetes in Zucker Diabetic Fatty Rats

The effect of nonacylated and acylated anthocyanins on urinary metabolites in diabetic rats was investigated. Nonacylated anthocyanins extract from bilberries (NAAB) or acylated anthocyanins extract from purple potatoes (AAPP) was given to Zucker diabetic fatty (ZDF) rats for 8 weeks at daily doses of 25 and 50 mg/kg body weight. ¹H NMR metabolomics was applied to study alterations in urinary metabolites from three time points (weeks 1, 4, and 8). Both types of anthocyanins modulated the metabolites associated with the tricarboxylic acid cycle, gut microbiota metabolism, and renal function at weeks 1 and 4, such as 2-oxoglutarate, fumarate, alanine, trigonelline, and hippurate. In addition, only a high dose of AAPP decreased monosaccharides, formate, lactate, and glucose levels at week 4, suggesting improvement in energy production in mitochondria, glucose homeostasis, and oxidative stress. This study suggested different impacts of AAPP and NAAB on the metabolic profile of urine in diabetes.

The Functional Roles of Lactobacillus acidophilus in Different Physiological and Pathological Processes

Probiotics are live microorganisms that can be consumed by humans in amounts sufficient to offer health-promoting effects. Owing to their various biological functions, probiotics are widely used in biological engineering, industry and agriculture, food safety, and the life and health fields. Lactobacillus acidophilus (L. acidophilus), an important human intestinal probiotic, was originally isolated from the human gastrointestinal tract and its functions have been widely studied ever since it was named in 1900. L. acidophilus has been found to play important roles in many aspects of human health. Due to its good resistance against acid and bile salts, it has broad application prospects in functional, edible probiotic preparations. In this review, we explore the basic characteristics and biological functions of L. acidophilus based on the research progress made thus far worldwide. Various problems to be solved regarding the applications of probiotic products and their future development are also discussed.

Bifidobacterium animalis subsp. lactis Bi-07 supports lactose digestion in vitro and in randomized, placebo- and lactase-controlled clinical trials

BACKGROUND

Probiotics may alleviate lactose maldigestion.

OBJECTIVES

The objective was to select a probiotic with high lactase activity and compare it with lactase and placebo in clinical trials.

METHODS

Bacterial cultures were screened for lactase activity in a model of the upper gastrointestinal (GI) tract. Bifidobacterium animalis subsp. lactis Bi-07 (Bi-07) counts were adjusted in subsequent experiments to correspond to 4500 Food Chemicals Codex (FCC) units of lactase, the amount in the European Food Safety Authority (EFSA)-approved health claim. Two crossover clinical trials, Booster Alpha and Booster Omega, were performed in participants with lactose intolerance, where 2 × 1012 CFUs Bi-07, 4662 FCC lactase, or placebo was consumed simultaneously with a lactose challenge, with 1-wk washouts between challenges. The trial designs were identical except for the source of lactose. Breath hydrogen concentration (BHC) was measured to assess the effect of the investigational products on lactose digestion, for which incremental area under the curve (iAUC) was the primary outcome. Peak BHC, cumulative BHC, and GI symptoms were secondary outcomes.

RESULTS

Bi-07 was superior to placebo in reducing BHC [iAUC, parts per million (ppm) ∙ h] in both trials (Booster Alpha: geometric least square mean ratio: 0.462; 95% CI: 0.249, 0.859; P = 0.016; Booster Omega: 0.227; 95% CI: 0.095, 0.543; P = 0.001). Lactase was superior to placebo in Booster Alpha (0.190; 95% CI: 0.102, 0.365; P < 0.001) but not Booster Omega (0.493; 95% CI: 0.210, 1.156; P = 0.102). Noninferiority of Bi-07 compared with lactase was observed in Booster Omega (0.460; 95% CI: 0.193, 1.096; P = 0.079; CI upper limit < 1.25 noninferiority margin). Odds of abdominal pain (compared with placebo: 0.32, P = 0.036) and flatulence (compared with placebo: 0.25, P = 0.007) were lower with lactase in Booster Alpha. Increased odds of nausea were seen with Bi-07 (compared with placebo: 4.0, P = 0.005) in Booster Omega.

CONCLUSIONS

Bi-07 has high lactase activity, and in 2 clinical trials, it supported lactose digestion in individuals with lactose intolerance.These trials were registered at clinicaltrials.gov as NCT03659747 (Booster Alpha) and NCT03814668 (Booster Omega).

Cysteine protected cells from H2O2-induced damage and promoted long-chain fatty acids synthesis in vivo to improve γ-aminobutyric acid production in Levilactobacillus brevis

Levilactobacillus brevis NPS-QW-145 isolated from kimchi is deficient in glutamate dehydrogenase-encoding gene (gdhA) to form glutamate, hence it required exogenous supplementation of glutamate/monosodium glutamate (MSG) for decarboxylation reaction to produce γ-aminobutyric acid (GABA). However, GABA conversion rate from MSG was relatively low. The individual effect of 20 amino acids on regulating GABA biosynthesis was investigated. Cysteine was selected to significantly improve GABA production from MSG. It was found that Lb. brevis was capable of producing H₂O₂, cysteine protected Lb. brevis against H₂O₂-induced oxidative damage to increase cell viability for the enhancement of GABA production. Moreover, cysteine promoted glucose consumption to produce acetyl-CoA for synthesizing long-chain fatty acids to significantly up-regulate GABA biosynthesis. These findings deciphered antioxidative capability of cysteine in Lb. brevis 145 and provided a theoretical basis for fatty acids synthesis-mediated GABA synthesis in Lb. brevis 145, and possibly in other lactic acid bacteria.

Pharmacological Efficacy of Probiotics in Respiratory Viral Infections: A Comprehensive Review

Mortality and morbidity from influenza and other respiratory viruses are significant causes of concern worldwide. Infections in the respiratory tract are often underappreciated because they tend to be mild and incapacitated. On the other hand, these infections are regarded as a common concern in clinical practice. Antibiotics are used to treat bacterial infections, albeit this is becoming more challenging since many of the more prevalent infection causes have acquired a wide range of antimicrobial resistance. Resistance to frontline treatment medications is constantly rising, necessitating the development of new antiviral agents. Probiotics are one of several medications explored to treat respiratory viral infection (RVI). As a result, certain probiotics effectively prevent gastrointestinal dysbiosis and decrease the likelihood of secondary infections. Various probiotic bacterias and their metabolites have shown immunomodulating and antiviral properties. Unfortunately, the mechanisms by which probiotics are effective in the fight against viral infections are sometimes unclear. This comprehensive review has addressed probiotic strains, dosage regimens, production procedures, delivery systems, and pre-clinical and clinical research. In particular, novel probiotics' fight against RVIs is the impetus for this study. Finally, this review may explore the potential of probiotic bacterias and their metabolites to treat RVIs. It is expected that probiotic-based antiviral research would be benefitted from this review's findings.

Probiotic activity traits in vitro and production of antimicrobial peptides by Lactobacillaceae isolates from pulque using Lactobacillus acidophilus NCFM as control

The objective of this work was to determine in vitro probiotic activity traits of 11 lactic acid bacteria (LAB) strains isolated from pulque obtained from three different locations in the Mexican states of Oaxaca and Puebla using the probiotic strain Lactobacillus acidophilus NCFM as a positive control, and to detect their production of antimicrobial peptides, including bacteriocins and peptidoglycan hydrolases (PGH). The LAB isolates were identified by sequencing of their 16S rRNA as belonging to four different genera of the Lactobacillaceae family: Lactiplantibacillus, Levilactobacillus, Lacticaseibacillus and Liquorilactobacillus, corresponding to the species plantarum, brevis, paracasei and ghanensis, respectively. Most of the strains showed resistance to high acidity (pH 2) and bile salts (0.5%), with survival rates up to 87 and 92%, respectively. In addition, most of the strains presented good antimicrobial activity against the foodborne pathogens Listeria monocytogenes, ECEC and Salmonella Typhi. The strain Liquorilactobacillus ghanensis RVG6, newly reported in pulque, presented an outstanding overall performance on the probiotic activity tests. In terms of their probiotic activity traits assessed in this work, the strains compared positively with the control L. acidophilus NCFM, which is a very-well documented probiotic strain. For the antimicrobial peptide studies, four strains presented bacteriocin-like mediated antibiosis and six had significant PGH activity, with two strains presenting outstanding overall antimicrobial peptide production: Lacticaseibacillus paracasei RVG3 and Levilactobacillus brevis UTMB2. The probiotic performance of the isolates was mainly dependent on strain specificity. The results obtained in this work can foster the revalorization of pulque as a functional natural product.

Improvement in Lactose Tolerance in Hypolactasic Subjects Consuming Ice Creams with High or Low Concentrations of Bifidobacterium bifidum 900791

Although Bifidobacterium bifidum expresses lactase activity, no clinical trials have determined its impact on lactose-intolerant subjects. This study evaluated whether acute and chronic ingestion of ice creams containing B. bifidum 900791 at high (10⁷ CFU/g) or low (10⁵ CFU/g) concentrations improved lactose tolerance in hypolactasic subjects. Fifty subjects were selected based on a positive lactose (20 g) hydrogen breath test (HBT0) and the presence of digestive symptoms. The recruited subjects were required to perform breath tests after the acute ingestion of: (1) ice cream containing 20 g of lactose without a probiotic (HBT1); (2) the same ice cream, accompanied by a lactase tablet (HBT2); (3) the same ice cream containing the low or high dose of probiotic (HBT3-LD and HBT3-HD); and (4) after the chronic consumption of the ice cream without (placebo) or with the low concentration of probiotic for 1 month (HBT4). Significant decreases in H₂ excretion during HBT2 and HBT3-HD as well as digestive symptoms during HBT2, HBT3-HD and HBT3-LD were observed compared to HBT0 and HBT1, while the orocecal transit time increased. Chronic consumption of the probiotic ice cream did not enhance lactose tolerance compared to the placebo. These results suggest that the acute ingestion of ice cream containing high or low concentrations of B. bifidum 900791 improves lactose tolerance in hypolactasic subjects.

In vitro gastrointestinal resistance of Lactobacillus acidophilus in some dairy products

In this study, different dairy products such as ice cream, yoghurt, white pickled cheese, and fermented acidophilus milk were manufactured by using either Lactobacillus acidophilus DSM 20,079 or Lactobacillus acidophilus NCFM. The counts of L. acidophilus in the samples on days 1, 15, and 30 of the storage were determined. Additionally, the samples contained L. acidophilus were passed through a dynamic gastrointestinal model designed in laboratory conditions to compare the protective effect of different dairy products on viability of L. acidophilus against stress factors of the gastrointestinal model. The counts of L. acidophilus NCFM and L. acidophilus DSM 20,079 in the samples decreased by between 0.04 and 0.37 log units and by between 0.11 and 0.27 log units, respectively, within 30 days of storage. During the passage through the gastrointestinal model, the highest percentage reduction in the counts of L. acidophilus was determined in yoghurt followed by fermented acidophilus milk, white pickled cheese, and ice cream, respectively. The reduction in the counts of L. acidophilus in the samples during the passage through the model increased with extension of storage time. The results of this study showed that the reduction in the counts L. acidophilus in the samples during the passage through the model was influenced significantly by the matrix of the dairy product and storage period.

Review and perspectives of enhanced volatile fatty acids production from acidogenic fermentation of lignocellulosic biomass wastes

Lignocellulosic biomass wastes are abundant resources that are usually valorized for methane-rich biogas via anaerobic digestion. Conversion of lignocellulose into volatile fatty acids (VFA) rather than biogas is attracting attention due to the higher value-added products that come with VFA utilization. This review consolidated the latest studies associated with characteristics of lignocellulosic biomass, the effects of process parameters during acidogenic fermentation, and the intensification strategies to accumulate more VFA. The differences between anaerobic digestion technology and acidogenic fermentation technology were discussed. Performance-enhancing strategies surveyed included (1) alkaline fermentation; (2) co-digestion and high solid-state fermentation; (3) pretreatments; (4) use of high loading rate and short retention time; (5) integration with electrochemical technology, and (6) adoption of membrane bioreactors. The recommended operations include: mesophilic temperature (thermophilic for high loading rate fermentation), C/N ratio (20-40), OLR (< 12 g volatile solids (VS)/(L·d)), and the maximum HRT (8-12 days), alkaline fermentation, membrane technology or electrodialysis recovery. Lastly, perspectives were put into place based on critical analysis on status of acidogenic fermentation of lignocellulosic biomass wastes for VFA production.

Effects of Sub-Lethal High Pressure Homogenization Treatment on the Adhesion Mechanisms and Stress Response Genes in Lactobacillus acidophilus 08

Cell surface hydrophobicity (CSH) and adhesion are very important phenotypical traits for probiotics that confer them a competitive advantage for the resilience in the human gastrointestinal tract. This study was aimed to understand the effects over time of a 50 MPa hyperbaric treatment on the surface properties of Lactobacillus acidophilus 08 including CSH, autoaggregation, and in vitro adhesion (mucin layer and Caco-2 cells). Moreover, a link between the hurdle applied and the expression of genes involved in the general stress response (groEL and clpP) and adhesion processes (efTu and slpA) was evaluated. High pressure homogenization (HPH) at 50 MPa significantly increased the CSH percentage (H%), autoaggregation and in vitro adhesion on mucin of L. acidophilus 08 cells compared with the untreated cells. Moreover, the hyperbaric hurdle induced an upregulation of the stress response genes groEL and ef-TU together with a down regulation of the clpP and S-layer slpA genes. Looking at the protein profile, HPH-treatment showed an increase in the number or intensity of protein bands at high and low molecular weights.

What Makes a Successful Donor? Fecal Transplant from Anxious-Like Rats Does Not Prevent Spinal Cord Injury-Induced Dysbiosis

Spinal cord injury (SCI) causes gut dysbiosis and an increased prevalence of depression and anxiety. Previous research showed a link between these two consequences of SCI by using a fecal transplant from healthy rats which prevented both SCI-induced microbiota changes and the subsequent development of anxiety-like behaviour. However, whether the physical and mental state of the donor are important factors in the efficacy of FMT therapy after SCI remains unknown. In the present study, rats received a fecal transplant following SCI from uninjured donors with increased baseline levels of anxiety-like behaviour and reduced proportion of Lactobacillus in their stool. This fecal transplant increased intestinal permeability, induced anxiety-like behaviour, and resulted in minor but long-term alterations in the inflammatory state of the recipients compared to vehicle controls. There was no significant effect of the fecal transplant on motor recovery in rehabilitative training, suggesting that anxiety-like behaviour did not affect the motivation to participate in rehabilitative therapy. The results of this study emphasize the importance of considering both the microbiota composition and the mental state of the donor for fecal transplants following spinal cord injury.

Characterization of Lactobacillus species proposed as probiotics

An isolated Lactobacillus from several various sources were identified depending on morphological, microscopically and biochemical tests in vitro analysis of probiotic properties that included: an ability to tolerate in different concentration of bile salt, survival in acidic conditions, their antimicrobial activity, and S-layer characterizations were carried out. It was noticed that isolates of Lactobacillus rhamnosus and L. delbrueckii have a broad activity of antimicrobial and found the isolate L. rhamnosus represented with a survival percentage 6.9% at pH 4.5 and 5.1% at pH 2.0) also L. rhamnosus (5.7% at pH 4.5 and 4.9% at pH 2.0) tolerated acidic media, Lactobacillus spp. has antimicrobial activity against all gram-positive and negative tested isolates. 70 kDa of S-layer protein bands were detected with whole-cell SDS-PAGE analysis, and it's predominant in cells of isolates which grown in MRS broth anaerobically. It was noticed that the collected Lactobacillus isolates could be used as probiotic.

Functional role of surface layer proteins of Lactobacillus acidophilus L-92 in stress tolerance and binding to host cell proteins

Lactobacillus acidophilus surface layer proteins (SLPs) self-assemble into a monolayer that is non-covalently bound to the outer surface of the cells. There they are in direct contact with the environment, environmental stressors and gut components of the host in which the organism resides. The role of L. acidophilus SLPs is not entirely understood, although SLPs seem to be essential for bacterial growth. We constructed three L. acidophilus L-92 strains, each expressing a mutant of the most abundant SLP, SlpA. Each carried a 12-amino acid c-myc epitope substitution at a different position in the protein. A strain was also obtained that expressed the SlpA paralog SlpB from an originally silent slpB gene. All four strains behaved differently with respect to growth under various stress conditions, such as the presence of salt, ox gall or ethanol, suggesting that SlpA affects stress tolerance in L. acidophilus L-92. Also, the four mutants showed differential in vitro binding ability to human host cell proteins such as uromodulin or dendritic cell (DC)-specific intercellular adhesion molecule-3 grabbing non-integrin (DC-SIGN). Furthermore, co-culture of murine immature DCs with a mutant strain expressing one of the recombinant SlpA proteins changed the concentrations of the cytokines IL-10 and IL-12. Our data suggest that SlpA and SlpB of L. acidophilus participate in bacterial stress tolerance and binding to uromodulin or DC-SIGN, possibly leading to effective immune-modification.

In Vivo Transcriptome of Lactobacillus acidophilus and Colonization Impact on Murine Host Intestinal Gene Expression

Lactobacillus acidophilus NCFM is a probiotic strain commonly used in dairy products and dietary supplements. Postgenome in vitro studies of NCFM thus far have linked potential key genotypes to its probiotic-relevant attributes, including gut survival, prebiotic utilization, host interactions, and immunomodulatory activities. To corroborate and extend beyond previous in vivo and in vitro functional studies, we employed a dual RNA sequencing (RNA-seq) transcriptomic approach to identify genes potentially driving the gut fitness and activities of L. acidophilus NCFM in vivo, and in parallel, examine the ileal transcriptional response of its murine hosts during monocolonization. Spatial expression profiling of NCFM from the ileum through the colon revealed a set of 134 core genes that were consistently overexpressed during gut transit. These in vivo core genes are predominantly involved in the metabolism of carbohydrates, amino acids, and nucleotides, along with mucus-binding proteins and adhesion factors, confirming their functionally important roles in nutrient acquisition and gut retention. Functional characterization of the highly expressed major S-layer-encoding gene established its indispensable role as a cell shape determinant and maintenance of cell surface integrity, essential for viability and probiotic attributes. Host colonization by L. acidophilus resulted in significant downregulation of several proinflammatory cytokines and tight junction proteins. Genes related to redox signaling, mucin glycosylation, and circadian rhythm modulation were induced, suggesting impacts on intestinal development and immune functions. Metagenomic analysis of NCFM populations postcolonization demonstrated the genomic stability of L. acidophilus as a gut transient and further established its safety as a probiotic and biotherapeutic delivery platform.IMPORTANCE To date, our basis for comprehending the probiotic mechanisms of Lactobacillus acidophilus, one of the most widely consumed probiotic microbes, was largely limited to in vitro functional genomic studies. Using a germfree murine colonization model, in vivo-based transcriptional studies provided the first view of how L. acidophilus survives in the mammalian gut environment, including gene expression patterns linked to survival, efficient nutrient acquisition, stress adaptation, and host interactions. Examination of the host ileal transcriptional response, the primary effector site of L. acidophilus, has also shed light into the mechanistic roles of this probiotic microbe in promoting anti-inflammatory responses, maintaining intestinal epithelial homeostasis and modulation of the circadian-metabolic axis in its host.

Probiotics and Gut Health in Athletes

PURPOSE OF REVIEW

To provide a focused analysis of the challenges to gut health in athletes and examine recent research aimed at determining the impact of probiotics on preventing gastrointestinal (GI) symptoms and loss of barrier function in athletes.

RECENT FINDINGS

Frequency and severity of GI symptoms during training or competition were reduced by approximately one-third in studies demonstrating efficacy. Improvement of GI symptoms with probiotic supplementation was measured in both single-strain Lactobacillus and multi-strain Lactobacillus and Bifidobacterim probiotics, while improvement in gut barrier function was only measured for multi-strain probiotics. Likelihood of efficacy increased with duration of supplementation. The greatest efficacy for reducing GI symptom frequency and severity, as well as improving or preserving gut barrier function during exercise training and competition, appears to be for multi-strain Lactobacillus and Bifidobacterium probiotic cocktails supplemented for at least 11 weeks.

The Microbiome and Its Implications in Cancer Immunotherapy

Cancer is responsible for ~18 million deaths globally each year, representing a major cause of death. Several types of therapy strategies such as radiotherapy, chemotherapy and more recently immunotherapy, have been implemented in treating various types of cancer. Microbes have recently been found to be both directly and indirectly involved in cancer progression and regulation, and studies have provided novel and clear insights into the microbiome-mediated emergence of cancers. Scientists around the globe are striving hard to identify and characterize these microbes and the underlying mechanisms by which they promote or suppress various kinds of cancer. Microbes may influence immunotherapy by blocking various cell cycle checkpoints and the production of certain metabolites. Hence, there is an urgent need to better understand the role of these microbes in the promotion and suppression of cancer. The identification of microbes may help in the development of future diagnostic tools to cure cancers possibly associated with the microbiome. This review mainly focuses on various microbes and their association with different types of cancer, responses to immunotherapeutic modulation, physiological responses, and prebiotic and postbiotic effects.

Impact of Media Heat Treatment on Cell Morphology and Stability of L. acidophilus, L. johnsonii and L. delbrueckii subsp. delbrueckii during Fermentation and Processing

Manufacturers of starter cultures and probiotics aim to provide preparations with the highest possible amount of living cells and assurance of long-term storage stability. Thereby the industrial economy and thus an efficient outcome of the processes is of utmost importance. Earlier research has shown that the sterilization procedure of the microbial culture medium tremendously impacts growth performance of heating product-sensitive Lactobacillus strains. Thus, three different strains, i.e., L. acidophilus NCFM, L. johnsonii La-2801 and L. delbrueckii subsp. delbrueckii La-0704, were investigated for the influence of media heat pretreatment on cell morphology and stability during fermentation and further freeze drying and storage. The data indicate a relationship between the heating time of the culture medium, which is associated with an increase in browning reactions, and the cultural characteristics of the three strains. The resulting characteristic cell sizes of the cultures could be a major reason for the different stability properties during processing and storage that were observed. Besides the obvious relevance of the results for the production of starter cultures and probiotics, the pleomorphic phenomenon described here could also be a subject for other biotechnological processes, where heat-mediated media conversions, and thereby related cellular effects, could be a topic. Future studies have to show if further functional properties are influenced by the cell morphology and which cellular mechanisms lead to the observed pleomorphism.

Development of a High-Resolution Single-Nucleotide Polymorphism Strain-Typing Assay Using Whole Genome-Based Analyses for the Lactobacillus acidophilus Probiotic Strain

Lactobacillus acidophilus is one of the most commonly used industrial products worldwide. Since its probiotic efficacy is strain-specific, the identification of probiotics at both the species and strain levels is necessary. However, neither phenotypic nor conventional genotypic methods have enabled the effective differentiation of L. acidophilus strains. In this study, a whole-genome sequence-based analysis was carried out to establish high-resolution strain typing of 41 L. acidophilus strains (including commercial isolates and reference strains) using the cano-wgMLST_BacCompare analytics platform; consequently, a strain-specific discrimination method for the probiotic strain LA1063 was developed. Using a core-genome multilocus sequence-typing (cgMLST) scheme based on 1390 highly conserved genes, 41 strains could be assigned to 34 sequence types. Subsequently, we screened a set of 92 loci with a discriminatory power equal to that of the 1390 loci cgMLST scheme. A strain-specific polymerase chain reaction combined with a multiplex minisequencing method was developed based on four (phoU, secY, tilS, and uvrA_1) out of 21 loci, which could be discriminated between LA1063 and other L. acidophilus strains using the cgMLST data. We confirmed that the strain-specific single-nucleotide polymorphisms method could be used to quickly and accurately identify the L. acidophilus probiotic strain LA1063 in commercial products.

S-layer associated proteins contribute to the adhesive and immunomodulatory properties of Lactobacillus acidophilus NCFM

BACKGROUND

Surface layers (S-layers) are two-dimensional crystalline arrays of repeating proteinaceous subunits that form the outermost layer of many bacterial cell envelopes. Within the Lactobacillus genus, S-layer presence is frequently associated with probiotic-relevant properties such as improved adherence to host epithelial cells and modulation of the immune response. However, recent studies have demonstrated that certain S-layer functions may be supplemented by a novel subset of proteins embedded within its lattice, termed S-layer associated proteins (SLAPs). In the following study, four Lactobacillus acidophilus NCFM SLAPs (LBA0046, LBA0864, LBA1426, and LBA1539) were selected for in silico and phenotypic assessment.

RESULTS

Despite lacking any sequence similarity or catalytic domains that may indicate function, the genes encoding the four proteins of interest were shown to be unique to S-layer-forming, host-adapted lactobacilli species. Likewise, their corresponding deletion mutants exhibited broad, host-relevant phenotypes including decreased inflammatory profiles and reduced adherence to Caco-2 intestinal cells, extracellular matrices, and mucin in vitro.

CONCLUSIONS

Overall, the data presented in this study collectively links several previously uncharacterized extracellular proteins to roles in the underlying host adaptive mechanisms of L. acidophilus.

An 1,4-α-Glucosyltransferase Defines a New Maltodextrin Catabolism Scheme in Lactobacillus acidophilus

The maltooligosaccharide (MOS) utilization locus in Lactobacillus acidophilus NCFM, a model for human small-intestine lactobacilli, encodes three glycoside hydrolases (GHs): a putative maltogenic α-amylase of family 13, subfamily 20 (LaGH13_20), a maltose phosphorylase of GH65 (LaGH65), and a family 13, subfamily 31, member (LaGH13_31B), annotated as a 1,6-α-glucosidase. Here, we reveal that LaGH13_31B is a 1,4-α-glucosyltransferase that disproportionates MOS with a degree of polymerization of ≥2, with a preference for maltotriose. Kinetic analyses of the three GHs encoded by the MOS locus revealed that the substrate preference of LaGH13_31B toward maltotriose complements the ~40-fold lower k _cat of LaGH13_20 toward this substrate, thereby enhancing the conversion of odd-numbered MOS to maltose. The concerted action of LaGH13_20 and LaGH13_31B confers the efficient conversion of MOS to maltose that is phosphorolyzed by LaGH65. Structural analyses revealed the presence of a flexible elongated loop that is unique for a previously unexplored clade of GH13_31, represented by LaGH13_31B. The identified loop insertion harbors a conserved aromatic residue that modulates the activity and substrate affinity of the enzyme, thereby offering a functional signature of this clade, which segregates from 1,6-α-glucosidases and sucrose isomerases previously described within GH13_31. Genomic analyses revealed that the LaGH13_31B gene is conserved in the MOS utilization loci of lactobacilli, including acidophilus cluster members that dominate the human small intestine.IMPORTANCE The degradation of starch in the small intestine generates short linear and branched α-glucans. The latter are poorly digestible by humans, rendering them available to the gut microbiota, e.g., lactobacilli adapted to the small intestine and considered beneficial to health. This study unveils a previously unknown scheme of maltooligosaccharide (MOS) catabolism via the concerted activity of an 1,4-α-glucosyltransferase together with a classical hydrolase and a phosphorylase. The intriguing involvement of a glucosyltransferase likely allows the fine-tuning of the regulation of MOS catabolism for optimal harnessing of this key metabolic resource in the human small intestine. The study extends the suite of specificities that have been identified in GH13_31 and highlights amino acid signatures underpinning the evolution of 1,4-α-glucosyl transferases that have been recruited in the MOS catabolism pathway in lactobacilli.

Human microbiome and prostate cancer development: current insights into the prevention and treatment

The huge communities of microorganisms that symbiotically colonize humans are recognized as significant players in health and disease. The human microbiome may influence prostate cancer development. To date, several studies have focused on the effect of prostate infections as well as the composition of the human microbiome in relation to prostate cancer risk. Current studies suggest that the microbiota of men with prostate cancer significantly differs from that of healthy men, demonstrating that certain bacteria could be associated with cancer development as well as altered responses to treatment. In healthy individuals, the microbiome plays a crucial role in the maintenance of homeostasis of body metabolism. Dysbiosis may contribute to the emergence of health problems, including malignancy through affecting systemic immune responses and creating systemic inflammation, and changing serum hormone levels. In this review, we discuss recent data about how the microbes colonizing different parts of the human body including urinary tract, gastrointestinal tract, oral cavity, and skin might affect the risk of developing prostate cancer. Furthermore, we discuss strategies to target the microbiome for risk assessment, prevention, and treatment of prostate cancer.

Probiotics for cancer alternative prevention and treatment

Cancer is a fatal malignancy with high clinical significance and remains one of the major causes of illness and death. It has no suitable cure existing till now. The safety and stability of the standard chemotherapeutics drugs and synthetic agents used to manage cancer are doubtful. These agents are affecting the quality of life or contributing for development of drug resistance and are not affordable to the majority of the patients. Therefore, scientists are looking into clinical management of the cancer with high efficiency. This review focuses on the role of probiotics as alternative prevention and treatment of cancer. In this regard, we discuss the alternative cancer biotherapeutic drugs including live or dead probiotics and their metabolites, such as short chain fatty acids, inhibitory compounds of protein, polysaccharide, nucleic acid and ferrichrome in in vitro, in vivo and clinical studies. We also discuss the effectiveness of these biotherapeutics in prevention and treatment of various types of cancer linked with probiotic bacterial or fungal strains, probiotic dose, and time of exposure. More in vivo mainly clinical trials are necessary to further reveal and approve the significant role of live and dead probiotics as well as their metabolic products in cancer prevention and treatment. Finally, the majority of the positive results provided by probiotic treatments are limited to experimental settings. To minimize side effects associated with probiotics, short and long term effect studies in the direction of methodology standardization are required.

Evodiamine has therapeutic efficacy in ulcerative colitis by increasing Lactobacillus acidophilus levels and acetate production

Emerging evidence implicates gut microbiota have an important role in ulcerative colitis (UC). Previous study indicated that Evodiamine (EVO) can alleviate colitis through downregulating inflammatory pathways. However, specific relationship between EVO-treated colitis relief and regulation of gut microbiota is still unclear. Here, our goal was to determine the potential role of gut microbiota in the relief of UC by EVO. By using pathology-related indicators, 16S rRNA sequencing and metabolomics profiling, we assessed the pharmacological effect of EVO on dextran sulfate sodium (DSS)-induced colitis rats as well as on the change of gut microbiota and metabolism. Fecal derived from EVO-treated rats was transplanted into colitis rats to verify the effect of EVO on gut microbiota, and 'driver bacteria' was found and validated by 16S rRNA sequencing, metagenome and qRT-PCR. The effect of Lactobacillus acidophilus (L. acidophilus) was investigated by vivo experiment, microbiota analysis, Short-chain fatty acids (SCFAs) quantification and colon transcriptomics. EVO reduced the susceptibility to DSS-induced destruction of epithelial integrity and severe inflammatory response, and regulated the gut microbiota and metabolites. Fecal Microbiota Transplantation (FMT) alleviated DSS-induced colitis, increased the abundance of L. acidophilus and the level of acetate. Furthermore, gavaged with L. acidophilus reduced pro-inflammatory cytokines, promoted the increase of goblet cells and the secretion of antimicrobial peptides, regulated the ratio of Firmicutes/Bacteroidetes and increased the level of acetate. Our results indicated that EVO mitigation of DSS-induced colitis is associated with increased in L. acidophilus and protective acetate production, which may be a promising strategy for treating UC.

Deletion of S-Layer Associated Ig-Like Domain Protein Disrupts the Lactobacillus acidophilus Cell Surface

Bacterial surface-layers (S-layers) are crystalline arrays of repeating proteinaceous subunits that coat the exterior of many cell envelopes. S-layers have demonstrated diverse functions in growth and survival, maintenance of cell integrity, and mediation of host interactions. Additionally, S-layers can act as scaffolds for the outward display of auxiliary proteins and glycoproteins. These non-covalently bound S-layer associated proteins (SLAPs) have characterized roles in cell division, adherence to intestinal cells, and modulation of the host immune response. Recently, IgdA (LBA0695), a Lactobacillus acidophilus SLAP that possesses a Group 3 immunoglobulin (Ig)-like domain and GW (Gly-Tryp) dipeptide surface anchor, was recognized for its high conservation among S-layer-forming lactobacilli, constitutive expression, and surface localization. These findings prompted its selection for examination within the present study. Although IgdA and corresponding orthologs were shown to be unique to host-adapted lactobacilli, the Ig domain itself was specific to vertebrate-adapted species suggesting a role in vertebrate adaptation. Using a counterselective gene replacement system, igdA was deleted from the L. acidophilus NCFM chromosome. The resultant mutant, NCK2532, exhibited a visibly disrupted cell surface which likely contributed to its higher salt sensitivity, severely reduced adhesive capacity, and altered immunogenicity profile. Transcriptomic analyses revealed the induction of several stress response genes and secondary surface proteins. Due to the broad impact of IgdA on the cellular physiology and probiotic attributes of L. acidophilus, identification of similar proteins in alternative bacterial species may help pinpoint next-generation host-adapted probiotic candidates.

Strain-Specific Probiotic Properties of Bifidobacteria and Lactobacilli for the Prevention of Diarrhea Caused by Rotavirus in a Preclinical Model

Probiotic supplementation with different lactobacilli and bifidobacterial strains has demonstrated beneficial effects in infectious diarrhea caused by rotavirus (RV) in young children. Preclinical models of RV infection might be a good strategy to screen for the efficacy of new probiotic strains or to test their comparative efficacy. Neonatal Lewis rats were supplemented with Bifidobacterium breve M-16V, Lactobacillus acidophilus NCFM, Lactobacillus helveticus R0052, or Lactobacillus salivarius PS2 from days 2–14 of life. On day five, animals received RV SA-11 orally. Fecal samples were collected daily, weighed, and scored for the calculation of severity and incidence of diarrhea. In addition, fecal pH and fecal viral shedding were measured. Animals were sacrificed at the end of the study and their blood was obtained for the quantification of RV-specific immunoglobulins. RV infection was induced in ~90% of the animals. All probiotics caused a reduction of several clinical variables of severity and incidence of diarrhea, except L. salivarius PS2. L. acidophilus NCFM, B. breve M-16V, and L. helveticus R0052 seemed to be very effective probiotic strains. In addition, all Lactobacillus strains reduced the viral elimination one day post-inoculation. No differences were detected in the specific anti-RV humoral response. The present study highlights the strain-specific effects of probiotics and identifies promising probiotics for use in ameliorating and preventing RV-induced diarrhea in children, for example by including them in infant formulas.

Probiotic supplementation attenuates the aggressiveness of chemically induced colorectal tumor in rats

To evaluate the effect of a probiotic on the aggressiveness of a chemically induced colorectal tumor in rats. Twenty-five male Fisher 344 rats, 250 g, provided with feed and water ad libitum, were randomly divided into 5 groups (5 rats/group): G_Control, no treatment; G_Tumor, tumor induction; G_Tumor+5FU, tumor induction, 5-Fluorouracil applied; G_Tumor+Prob, induction of the tumor, supplemented with probiotic; G_{Tumor+5-FU+Prob}, tumor induction, 5-Fluorouracil applied, supplemented with probiotic. For tumor induction 20 mg/kg of 1,2-dimethylhydrazine was applied intraperitoneally over 4 weeks, followed by an interval of 15 days, and then repeated for a further 4 weeks. Five weeks after the final dose of the carcinogen, treatment was initiated with 5-Fluorouracil (15 mg/kg, intraperitoneally/week) and a commercial probiotic (1 × 10⁹ CFU, daily/gavage). Data were analyzed by One Way Variance Analysis and means compared by Dunnett's test. GraphPad Prism statistical software was used. The histopathological analyzes were evaluated by the chi-square test. A 5% type-I error was considered statistically significant. Compared with the G_Tumor, the G_Tumor+Prob (p < 0.0373) and G_{Tumor+5-FU+Prob} (p < 0.0003) demonstrated an attenuated effect on the aggressiveness of the colorectal tumor, with a reduction in the count of Aberrant Crypt foci; and a lower percentage of malignant neoplastic lesions in the G_Tumor+Prob (40% low grade tubular adenoma, 40% carcinoma in situ, 20% low grade adenocarcinoma) and G_{Tumor+5-FU+Prob} (40% low grade tubular adenoma and 60% carcinoma in situ). Probiotic supplementation has the potential to decrease the formation of aberrant crypts and ameliorate tumor malignancy, enhancing the antitumor effect of 5-Fluorouracil chemotherapy in colic segments.

Effect of Lactobacillus acidophilus, Oenococcus oeni, and Lactobacillus brevis on Composition of Bog Bilberry Juice

This study investigated the impact of Lactobacillus acidophilus NCFM, Oenococcus oeni Viniflora^® Oenos and Lactobacillus brevis CICC 6239 on bog bilberry juice with a considerably low pH and rich in anthocyanins content. Moreover, the effects of the strains on the composition of phenolic compounds, amino acids, ammonium ion, biogenic amines, reduced sugars, organic acids, and color parameters of the juice were studied. All three bacteria consumed sugars and amino acids but exhibited different growth patterns. Lactic acid was detected only in L. acidophilus inoculated juice. The content of the phenolic compounds, especially anthocyanins, decreased in juice after inoculation. The CIELa*b* analysis indicated that the juice inoculated with L. acidophilus and O. oeni showed a decrease on a* and b* (less red and yellow) but an increase on L (more lightness), whereas the color attributes of L. brevis inoculated juice did not significantly change. Based on this study, L. brevis showed the most optimal performance in the juice due to its better adaptability and fewer effects on the appearance of juice. This study provided a useful reference on the metabolism of lactic acid bacteria in low pH juice and the evolution of primary and secondary nutrients in juice after inoculated with lactic acid bacteria.

Isolation and characterization of Lactobacillus-derived membrane vesicles

Bacterial membrane vesicles have been implicated in a broad range of functions in microbial communities from pathogenesis to gene transfer. Though first thought to be a phenomenon associated with Gram-negative bacteria, vesicle production in Staphylococcus aureus, Lactobacillus plantarum, and other Gram-positives has recently been described. Given that many Lactobacillus species are Generally Regarded as Safe and often employed as probiotics, the engineering of Lactobacillus membrane vesicles presents a new avenue for the development of therapeutics and vaccines. Here we characterize and compare the membrane vesicles (MVs) from three different Lactobacillus species (L. acidophilus ATCC 53544, L. casei ATCC 393, and L. reuteri ATCC 23272), with the aim of developing future strategies for vesicle engineering. We characterize the vesicles from each Lactobacillus species comparing the physiochemical properties and protein composition of each. More than 80 protein components from Lactobacillus-derived MVs were identified, including some that were enriched in the vesicles themselves suggesting vesicles as a vehicle for antimicrobial delivery. Additionally, for each species vesicular proteins were categorized based on biological pathway and examined for subcellular localization signals in an effort to identify possible sorting mechanisms for MV proteins.

Stimulatory effects of novel glucosylated lactose derivatives GL34 on growth of selected gut bacteria

Previously we structurally characterized five glucosylated lactose derivatives (F1-F5) with a degree of polymerization (DP) of 3-4 (GL34), products of Lactobacillus reuteri glucansucrases, with lactose and sucrose as substrates. Here, we show that these GL34 compounds are largely resistant to the hydrolytic activities of common carbohydrate-degrading enzymes. Also, the ability of single strains of gut bacteria, bifidobacteria, lactobacilli, and commensal bacteria, to ferment the GL34 compounds was studied. Bifidobacteria clearly grew better on the GL34 mixture than lactobacilli and commensal bacteria. Lactobacilli and the commensal bacteria Escherichia coli Nissle and Bacteroides thetaiotaomicron only degraded the F2 compound α-D-Glcp-(1 → 2)-[β-D-Galp-(1 → 4)-]D-Glcp, constituting around 30% w/w of GL34. Bifidobacteria digested more than one compound from the GL34 mixture, varying with the specific strain tested. Bifidobacterium adolescentis was most effective, completely degrading four of the five GL34 compounds, leaving only one minor constituent. GL34 thus represents a novel oligosaccharide mixture with (potential) synbiotic properties towards B. adolescentis, synthesized from cheap and abundantly available lactose and sucrose.

Engineering Components of the Lactobacillus S-Layer for Biotherapeutic Applications

Lactic acid bacteria (LAB) are frequently harnessed for the delivery of biomolecules to mucosal tissues. Several species of Lactobacillus are commonly employed for this task, of which a subset are known to possess surface-layers (S-layers). S-layers are two-dimensional crystalline arrays of repeating proteinaceous subunits that form the outermost coating of many prokaryotic cell envelopes. Their periodicity and abundance have made them a target for numerous biotechnological applications. In the following review, we examine the multi-faceted S-layer protein (Slp), and its use in both heterologous protein expression systems and mucosal vaccine delivery frameworks, through its diverse genetic components: the strong native promoter, capable of synthesizing as many as 500 Slp subunits per second; the signal peptide that stimulates robust secretion of recombinant proteins; and the structural domains, which can be harnessed for both cell surface display of foreign peptides or adhesion enhancement of a host bacterium. Although numerous studies have established vaccine platforms based on one or more components of the Lactobacillus S-layer, this area of research still remains largely in its infancy, thus this review is meant to not only highlight past works, but also advocate for the future usage of Slps in biotherapeutic research.

Surface-Layer Protein from Lactobacillus acidophilus NCFM Inhibits Lipopolysaccharide-Induced Inflammation through MAPK and NF-κB Signaling Pathways in RAW264.7 Cells

The objective of our research was to evaluate the molecular mechanism of the anti-inflammatory effects of surface-layer protein (Slp) derived from Lactobacillus acidophilus NCFM in lipopolysaccharide-induced RAW264.7 cells. Our results presented that Slp, with an apparent size of 46 kDa, attenuated the production of TNF-α, IL-1β, and reactive oxygen species (ROS), by inhibiting the MAPK and NF-κB signaling pathways. In addition, 10 μg mL^-1 of Slp significantly inhibited NO and PGE₂ production ( P < 0.001) through downregulating the expression levels of iNOS and COX-2 protein. Furthermore, Slp was found to inhibit NF-κB p65 translocation into the nucleus to activate inflammatory gene transcription. These findings suggest that Slp is a potential immune-modulating bioactive protein derived from probiotics and holds promise for use as an additive in functional foods.

Increases in Phenolic, Fatty Acid, and Phytosterol Contents and Anticancer Activities of Sweet Potato after Fermentation by Lactobacillus acidophilus

Phenolic, fatty acid, and phytosterol contents in sweet potato (SP) fermented by Lactobacillus acidophilus were evaluated and compared with those of raw and boiled SPs. The differences in the profiles and levels of phenolics between the raw and boiled SPs were not as significant as the differences between those and the fermented SP. The levels of caffeic acid and 3,5-dicaffeoylquinic acid in fermented SP were more than 4 times higher than those in raw and boiled SPs. Two phenolics, p-coumaric acid and ferulic acid, which were not detected in either raw or boiled SP, were found in fermented SP. The level of each fatty acid or phytosterol increased in fermented SP and decreased in boiled SP. Among the hydrophilic and lipophilic extracts obtained from raw and fermented SPs, the hydrophilic extract of fermented SP exhibited the highest capability of inhibiting cancer-cell PC-12 proliferation. However, each of the extracts had very low cytotoxicities to normal-monkey-kidney-cell growth. The results indicated that SP fermented by L. acidophilus significantly increased free antioxidant-rich phenolics and inhibited cancer-cell-proliferation activity without cytotoxicity to normal cells.