The prebiotic source influences the growth, biochemical features and survival under simulated gastrointestinal conditions of the probiotic Lactobacillus acidophilus

Journey of the Probiotic Bacteria: Survival of the Fittest

This review aims to bring a more general view of the technological and biological challenges regarding production and use of probiotic bacteria in promoting human health. After a brief description of the current concepts, the challenges for the production at an industrial level are presented from the physiology of the central metabolism to the ability to face the main forms of stress in the industrial process. Once produced, these cells are processed to be commercialized in suspension or dried forms or added to food matrices. At this stage, the maintenance of cell viability and vitality is of paramount for the quality of the product. Powder products requires the development of strategies that ensure the integrity of components and cellular functions that allow complete recovery of cells at the time of consumption. Finally, once consumed, probiotic cells must face a very powerful set of physicochemical mechanisms within the body, which include enzymes, antibacterial molecules and sudden changes in pH. Understanding the action of these agents and the induction of cellular tolerance mechanisms is fundamental for the selection of increasingly efficient strains in order to survive from production to colonization of the intestinal tract and to promote the desired health benefits.

The Promising Role of Microbiome Therapy on Biomarkers of Inflammation and Oxidative Stress in Type 2 Diabetes: A Systematic and Narrative Review

Background

One in 10 adults suffer from type 2 diabetes (T2D). The role of the gut microbiome, its homeostasis, and dysbiosis has been investigated with success in the pathogenesis as well as treatment of T2D. There is an increasing volume of literature reporting interventions of pro-, pre-, and synbiotics on T2D patients.

Methods

Studies investigating the effect of pro-, pre-, and synbiotics on biomarkers of inflammation and oxidative stress in T2D populations were extracted from databases such as PubMed, Scopus, Web of Science, Embase, and Cochrane from inception to January 2022.

Results

From an initial screening of 5,984 hits, 47 clinical studies were included. Both statistically significant and non-significant results have been compiled, analyzed, and discussed. We have found various promising pro-, pre-, and synbiotic formulations. Of these, multistrain/multispecies probiotics are found to be more effective than monostrain interventions. Additionally, our findings show resistant dextrin to be the most promising prebiotic, followed closely by inulin and oligosaccharides. Finally, we report that synbiotics have shown excellent effect on markers of oxidative stress and antioxidant enzymes. We further discuss the role of metabolites in the resulting effects in biomarkers and ultimately pathogenesis of T2D, bring attention toward the ability of such nutraceuticals to have significant role in COVID-19 therapy, and finally discuss few ongoing clinical trials and prospects.

Conclusion

Current literature of pro-, pre- and synbiotic administration for T2D therapy is promising and shows many significant results with respect to most markers of inflammation and oxidative stress.

Acute and short-term effects of Lactobacillus paracasei subsp. paracasei 431 and inulin intake on appetite control and dietary intake: A two-phases randomized, double blind, placebo-controlled study

This study aims to examine the acute and short-term effects of prebiotics, probiotics, and their combination on appetite, energy intake and satiety related hormones in two phases. The first phase was a randomized, double blind, placebo controlled crossover study. Prebiotic (16 g inulin), probiotic (Lactobacillus paracasei subsp. paracasei 431 (L. casei 431) (>10⁶ cfu/ml), synbiotic (their combination) and control (16 g maltodextrin) dairy drinks were consumed by 16 healthy men with a standard breakfast on four separate test days, and the following satiety responses and ad libitum food intake at lunch and over 24 h were assessed. In the second phase, the effects of 21 days of synbiotic (n = 10) or control (n = 11) drink consumption on appetite sensation, energy intake, serum glucose, insulin, peptide YY, ghrelin, obestatin and adiponectin concentration were assessed in a randomized double-blind placebo-controlled design. In the first phase, energy intake values during ad libitum lunch were the lowest in the prebiotic drink, followed by probiotic, synbiotic and control drinks, respectively (p = 0.017); also the rest of the day and 24-h dietary energy intake was lower by prebiotic and probiotic drinks compared to the control drink (p < 0.05 for each). For short-term effects, no significant difference in anthropometric measurements, hunger-satiety scores and serum glucose, insulin, PYY, ghrelin, obestatin and adiponectin concentrations were recorded. Despite the potential of prebiotics and probiotics to reduce energy intake, further studies are required for a better understanding of their role in satiety related mechanisms.

Probiotic potential and safety assessment of bacteriocinogenic Enterococcus faecium strains with antibacterial activity against Listeria and vancomycin-resistant enterococci

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Bacteriocinogenic Enterococcus faecium strains were evaluated for their beneficial and safety properties.

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Safety of the strains were evaluated based on phenotypic and bio-molecular approaches.

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The beneficial properties of the strains were demonstrated.

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High survivability under simulated GIT conditions and inhibition of Listeria spp. were demonstrated.

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The strains were found to carry genes coding for GABA production.

Enterococcus spp., known for their wide ecological distribution, have been associated with various fermented food products of plant and animal origin. The strains used in this study, bacteriocinogenic Enterococcus faecium previously isolated from artisanal soybean paste, have shown strong activity against Listeria spp. and vancomycin-resistant enterococci. Although their antimicrobial activity is considered beneficial, the potential application of enterococci is still under debate due to concerns about their safety for human and other animal consumption. Therefore, this study not only focuses on the screening of potential virulence factors, but also the auxiliary beneficial properties of the strains Ent. faecium ST651ea, ST7119ea, and ST7319ea. Phenotypic screening for gelatinase, hemolysin, and biogenic amine production showed that the strains were all safe. Furthermore, the antibiogram profiling showed that all the strains were susceptible to the panel of antibiotics used in the assessment except for erythromycin. Yet, Ent. faecium ST7319ea was found to carry some of the virulence genes used in the molecular screening for safety including hyl, esp, and IS16. The probiotic potential and other beneficial properties of the strains were also studied, demonstrating high aggregation and co-aggregation levels compared to previously characterized strains, in addition to high survivability under simulated gastrointestinal conditions, and production of numerous desirable enzymes as evaluated by APIZym, indicating diverse possible biotechnological applications of these strains. Additionally, the strains were found to carry genes coding for γ-aminobutyric acid (GABA) production, an auxiliary characteristic for their probiotic potential. Although these tests showed relatively favorable characteristics, it should be considered that these assays were carried out in vitro and should therefore also be assessed under in vivo conditions.

Development of a functional synbiotic beverage fortified with different cereal sprouts and prebiotics

Abstract

The study was devoted to developing a novel synbiotic beverage based on with millet, rye and alfalfa sprouts with a mixed culture of Lactobacillus casei and Lactobacillus plantarum. In this regard, the influences of incorporated prebiotics inulin and oligofructose on probiotics viability during the refrigerated storage (4 ± 1 °C, 28 days) as well as under the simulated gastric condition were investigated. The characteristics such as microbial viability, physicochemical properties (viscosity, pH, titrable acidity and radical scavenging activity) and sensorial evaluation were assessed. The synbiotic beverage produced contained 10⁸ CFU ml^-1 for L. casei, with a good survival throughout the storage period (10⁸ CFU ml^-1) and L. plantarum at sufficient levels (10⁶ CFU ml^-1) after about 21 days. Inulin and oligofructose promoted the growth of the strains and their viability under cold storage while conferring higher sensory scores. In this context, the beverages demonstrated acceptable sensory attributes. The viability (bacterial survival) of over 55% for all the strains was achieved under simulated gastric condition. Therefore, the introduced fermented beverage was a good food matrix from the viability of probiotics as well as under the gastric condition and sensory characteristics.

Graphic abstract

Survival of Lactobacillus paracasei subsp. paracasei LBC 81 in Fermented Beverage from Chickpeas and Coconut in a Static In Vitro Digestion Model

The objective of this study was to evaluate in a static in vitro digestion model the survival of Lactobacillus paracasei subsp. paracasei LBC 81 in fermented chickpea and coconut beverage. The fermented beverage was stored for 1 and 8 days at 4 °C and then submitted to gastric juice, pancreatic juice, or sequential exposure to gastric and pancreatic juice. The experiment controls were (i) control 1—suspension of cells in 0.85% saline solution; (ii) control 2—cell suspension in chickpea and coconut beverage. The survival of L. paracasei was determined in log CFU/mL and expressed as a survival percentage. The survival of L. paracasei in the fermented beverage after exposure to gastric juice and sequential exposure to gastric and pancreatic juice was 99.47 + 2.05% and 93.21 + 0.43%, respectively. These values were higher than those found for controls 1 and 2. The storage condition of the fermented beverage for 1 or 8 days at 4 °C did not affect the survival after exposure to gastric juice, pancreatic juice, or sequential exposure. The results obtained in this study conclude that the fermented beverage of chickpeas and coconut is an excellent carrier for L. paracasei LBC 81, capable of enhancing survival to gastrointestinal conditions and ensuring a greater number of viable cells reaching the intestinal epithelium.

Modulating the Microbiota as a Therapeutic Intervention for Type 2 Diabetes

Mounting evidence suggested that the gut microbiota has a significant role in the metabolism and disease status of the host. In particular, Type 2 Diabetes (T2D), which has a complex etiology that includes obesity and chronic low-grade inflammation, is modulated by the gut microbiota and microbial metabolites. Current literature supports that unbalanced gut microbial composition (dysbiosis) is a risk factor for T2D. In this review, we critically summarize the recent findings regarding the role of gut microbiota in T2D. Beyond these associative studies, we focus on the causal relationship between microbiota and T2D established using fecal microbiota transplantation (FMT) or probiotic supplementation, and the potential underlying mechanisms such as byproducts of microbial metabolism. These microbial metabolites are small molecules that establish communication between microbiota and host cells. We critically summarize the associations between T2D and microbial metabolites such as short-chain fatty acids (SCFAs) and trimethylamine N-Oxide (TMAO). Additionally, we comment on how host genetic architecture and the epigenome influence the microbial composition and thus how the gut microbiota may explain part of the missing heritability of T2D found by GWAS analysis. We also discuss future directions in this field and how approaches such as FMT, prebiotics, and probiotics supplementation are being considered as potential therapeutics for T2D.

Probiotics, Pre-biotics and Synbiotics in the Treatment of Pre-diabetes: A Systematic Review of Randomized Controlled Trials

Objectives: This study aimed to review the data from randomized controlled trials (RCTs) and identify evidence for microbiota's role and use of probiotics, pre-biotics, or synbiotics in pre-diabetes. Methods: RCTs of pro-, pre-, synbiotics for the treatment of pre-diabetes population will be summarized. We searched for EMBASE, MEDLINE, Web of Science, Cochrane Central, Clinical Trials (ClinicalTrials.gov) from inception to February 2021. Results: The gut microbiota influences host metabolic disorders via the modulation of metabolites, including short-chain fatty acids (SCFAs), the endotoxin lipopolysaccharides (LPS), bile acids (BA) and trimethylamine N-oxide (TMAO), as well as mediating the interaction between the gastrointestinal system and other organs. Due to the limited sources of studies, inconsistent outcomes between included studies. Probiotics can decrease glycated hemoglobin (HbA1c) and have the potential to improve post-load glucose levels. The supplementation of probiotics can suppress the rise of blood cholesterol, but the improvement cannot be verified. Pre-biotics are failed to show an evident improvement in glycemic control, but their use caused the changes in the composition of gut microbiota. A combination of probiotics and pre-biotics in the synbiotics supplementation is more effective than probiotics alone in glycemic control. Conclusion: In the current studies using probiotics, pre-biotics or synbiotics for the treatment of pre-diabetes, the benefits of modulating the abundance of gut microbiota were partially demonstrated. However, there is insufficient evidence to show significant benefits on glucose metabolism, lipid metabolism and body composition.

Unravelling the involvement of gut microbiota in type 2 diabetes mellitus

Type 2 diabetes mellitus is the most prevalent metabolic disorder characterized by hyperglycemia, hyperlipidemia as well as insulin resistance and is affecting the lives of a huge population across the globe. Genetic mutations, obesity and lack of physical activity constitute the possible factors that can lead to onset and progression of this disorder. However, there is another major factor that can be the root cause of type 2 diabetes mellitus and that is an imbalance in the microorganisms that inhabit the gut. The gut microbiome is a vital component that needs to be given significant attention because any "dysbiosis" in the colonic microorganisms can transform the host from a state of health to a state of disease. This transformation is quite obvious since the gut barrier integrity, host metabolism such as sensitivity to insulin and maintaining blood glucose level are carried out by the tiny organisms inhabiting our intestine. In fact, the normal functioning of the human body is accredited to the microbes, particularly the bacteria, because they generate their metabolites that communicate with host cells and maintain normal physiology. Giving importance to gut health is, therefore, necessary to prevent metabolic diseases that can be maintained by the intake of prebiotics, probiotics, synbiotics along with healthy diet. The tiny microorganisms in the gut that keep our body free of disorders such as type 2 diabetes mellitus need to be in a state of 'eubiosis', else the consequences of disturbance in gut microbes can progress to serious complications in the host.

The In Vitro Analysis of Prebiotics to Be Used as a Component of a Synbiotic Preparation

Prebiotics are food components that are selectively fermented by beneficial microbiota and which confer a health benefit. The aim of the study was to select a prebiotic for the chosen probiotic strains to create a synbiotic. The impact of prebiotics (inulin, maltodextrin, corn starch, β-glucan, and apple pectin) on five Lactobacillus spp. strains' growth and metabolites synthesis (lactic, acetic, propionic, and butyric acids, ethanol, and acetaldehyde) was tested by the plate count method and by high-performance liquid chromatography, respectively. Moreover, the differences in the ratio of D(-) and L(+) lactate isomers produced by Lactobacillus spp., as well as variations in the probiotics' enzymatic profiles associated with the prebiotic used for cultivation, were determined with a Megazyme rapid assay kit and API® ZYM assay, accordingly. Finally, the influence of the carbon source (prebiotic) used on the antagonistic activity of the probiotic strains towards pathogenic bacteria, such as Salmonella spp. or Listeria monocytogenes was analyzed in the co-cultures. The results showed that the growth, metabolic profile, and antagonistic activity of the probiotics towards selected pathogens were the most favorable when 2% (w/v) of inulin was used. Therefore, the combination of inulin with selected probiotics is a promising synbiotic mixture.

From role of gut microbiota to microbial-based therapies in type 2-diabetes

The incidence of type 2 diabetes mellitus (T2DM) has increased dramatically at an alarming level around the world.T2DM is associated with changeable risk factors in lifestyle as well as genetic and family associated risk factors. More importantly, imbalanced or impaired gut microbial distribution (dysbiosis) has been reported as a contributing risk factor in insulin resistance progression in T2DM. Dysbiosis may restructure the metabolic and functional pathways in the intestine which are involved in the development of T2DM. However, several studies have indicated the constructive and helpful effect of prebiotics, probiotics, and fecal microbiota transplantation (FMT) on the improvement of gut microbiota (GM) and accordingly host metabolism. In this review, the association between GM and T2DM have been evaluated and the role of prebiotics, probiotics and FMT, as potential therapeutic approaches have been discussed. Relevant studies were obtained randomly from online databases such as PubMed/Medline and ISI Web of Science.

A new delivery system based on apple pomace-pectin gels to encourage the viability of antimicrobial strains

This work was aimed to investigate the concept of the valorization of apple processing by-products to produce a new preservation system based on apple pomace gels to encourage the viability of antimicrobial Lactobacillus strains. A high frequency (850 kHz) low power (1.3 W/cm²) ultrasound-stimulated cavitation was used for the structure modulating of gels under low-temperature (50 ℃) conditions. Medium esterified apple pectin was added to apple pomace to improve its texture properties and stability. The monitoring of the process of gelation was performed by using acoustic technique and method, based on the measurement of the distance (parameter h, mm) traveled by a free-falling module. The obtained data were then compared to gel texture measurements. The results suggest that low power ultrasound leads to a reduced jelly mass stickiness and increased gel hardness, compared to the thermally treated sample. The immobilization of probiotic cells in low pectin apple pomace gels did not sufficiently protect the microorganisms. The higher viability of immobilized Lactobacillus paracasei (54-77%) compared to L. plantarum (43-59%) was recorded after incubation at acidic conditions (pH 2.0). The most suitable system for preserving bacterial cells during storage can be the apple pomace-pectin gel containing up to 53% pectin as a stabilizer retaining 84% of viable cells after one-month storage at 4 ℃. The apple pomace-pectin hydrogels with gelation rate (dh/dt) of 0.03-0.05 mm/s can be used for the preservation of bacterial cells as a suitable functional ingredient for food.

In vitro fermentation of oligosaccharides obtained from enzymatic hydrolysis of Opuntia streptacantha mucilage

BACKGROUND

Among Cactaceae, the genus Opuntia is widely known for the use of its biomass as cattle fodder and in human nutrition (e.g. species such as Opuntia ficus indica and Opuntia streptacantha). In particular, O. streptacantha (OS) produces abundant mucilage and, hence, the characterization of its properties and nutritional value is important. Accordingly, determination of the dietary fiber content of the OS mucilage and the fermentability of its hydrolysis products (oligosaccharides, OLI) is important for developing new uses of the crop as a functional food.

RESULTS

The values for insoluble dietary fiber and soluble dietary fiber in the mucilage were 204.6 and 371.6 g kg^-1 , respectively. After hydrolysis of OS mucilage with α-amylase, three purified fractions of OLI were evaluated (OLI-A, OLI-B and OLI-C). OLI (1% w/v) stimulated the growth of the commercial probiotic strains (Lactobacillus acidophilus, Lactobacillus casei and Bifidobacterium animalis subsp. lactis) in vitro, showing behaviors similar to those of commercial inulin. The production of short chain fatty acids (SCFAs) in the fermentation broth was also determined. The final pH of the fermentation broth as well as the identification and concentrations of SCFA depended on the type of OLI and probiotic used.

CONCLUSION

The OS mucilage is an unconventional fiber source and can be used to produce non-digestible OLI as functional compounds. This knowledge will be useful for proposing new sustainable ways of processing cacti crops for food and industrial purposes. © 2018 Society of Chemical Industry.

Enrichment of Probiotic Fermented Milk with Green Banana Pulp: Characterization Microbiological, Physicochemical and Sensory

The aims of this study were (i) to evaluate the growth kinetic of L. paracasei LBC 81 in fermented milks enriched with green banana pulp (GBP); (ii) to evaluate the effect of the incorporation of GBP on the chemical composition and the sensory acceptance; and (iii) to study the viability of the probiotic and technological properties during refrigerated storage. The amount of GBP used were 3.0, 6.0 and 9.0 g/100 g. The results show that the higher the concentration of GBP added, the shorter the time taken to reach pH 4.6. It was observed that the incorporation of GBP did not affect negatively the viability of L. paracasei LBC 81 during storage. The fermented milk elaborated with 6.0 g/100 g of GBP was the most accepted. The present study indicates that the enrichment of fermented milk with GBP favors the stability of the probiotic strain, L. paracasei LBC 81 during storage.

Probiotics, prebiotics, synbiotics and insulin sensitivity

Animal studies indicate that the composition of gut microbiota may be involved in the progression of insulin resistance to type 2 diabetes. Probiotics and/or prebiotics could be a promising approach to improve insulin sensitivity by favourably modifying the composition of the gut microbial community, reducing intestinal endotoxin concentrations and decreasing energy harvest. The aim of the present review was to investigate the effects of probiotics, prebiotics and synbiotics (a combination of probiotics and prebiotics) on insulin resistance in human clinical trials and to discuss the potential mechanisms whereby probiotics and prebiotics improve glucose metabolism. The anti-diabetic effects of probiotics include reducing pro-inflammatory cytokines via a NF-κB pathway, reduced intestinal permeability, and lowered oxidative stress. SCFA play a key role in glucose homeostasis through multiple potential mechanisms of action. Activation of G-protein-coupled receptors on L-cells by SCFA promotes the release of glucagon-like peptide-1 and peptide YY resulting in increased insulin and decreased glucagon secretion, and suppressed appetite. SCFA can decrease intestinal permeability and decrease circulating endotoxins, lowering inflammation and oxidative stress. SCFA may also have anti-lipolytic activities in adipocytes and improve insulin sensitivity via GLUT4 through the up-regulation of 5'-AMP-activated protein kinase signalling in muscle and liver tissues. Resistant starch and synbiotics appear to have favourable anti-diabetic effects. However, there are few human interventions. Further well-designed human clinical studies are required to develop recommendations for the prevention of type 2 diabetes with pro- and prebiotics.

Evaluation of the prebiotic effects of citrus pectin hydrolysate

Citrus pectin enzyme hydrolysate (PEH) of different hydrolysis time intervals (6 hours, PEH-6; 12 hours, PEH-12; 24 hours, PEH-24; or 48 hours, PEH-48) or concentrations (1%, 2%, and 4%) was tested for its growth stimulation effect on two probiotics, Bifidobacterium bifidum and Lactobacillus acidophilus. Higher monosaccharide concentrations and smaller molecular weights of PEHs were obtained by prolonging the hydrolysis time. In addition, higher PEH concentrations resulted in significantly higher (p < 0.05) probiotic populations, pH reduction, and increase in total titratable acidity than the glucose-free MRS negative control. Furthermore, significantly higher populations in the low pH environment and longer survival time in nonfat milk (p < 0.05) were observed when the two probiotics were incubated in media supplemented with 2% PEH-24, than in glucose and the negative control. In comparison with other prebiotics, addition of 2% PEH-24 resulted in a more significant increase in the probiotic population (p < 0.05) than in the commercial prebiotics. This study demonstrated that PEH derived from citrus pectin could be an effective prebiotic to enhance the growth, fermentation, acid tolerance, and survival in nonfat milk for the tested probiotics.

Effect of Inulin on the Viability of L. plantarum during Storage and In Vitro Digestion and on Composition Parameters of Vegetable Fermented Juices

The prebiotic effect of different concentrations of inulin (0, 1 and 2%) on the growth and survival of Lactobacillus plantarum (LP) CECT 220 in blended carrot and orange juices was investigated after 24 h of fermentation, during 30 days of storage at 4 °C and through the phases of gastrointestinal digestion after different storage periods. Microbiological and chemical determinations were also carried out in all juices. The lactic fermentation increased the shelf life of the fermented juices with inulin. The hygienic-sanitary quality in fermented juices was better than the control juices. During storage, the inulin improved the viability of LP and the monosaccharide concentration remained higher with respect to the juice without inulin (40% lower). At 30 days, the fermented juices with 2% inulin after in vitro digestion presented the highest survival of L. plantarum.

Fermentation of Dietetic Fiber from Green Bean and Prickly Pear Shell by Pure and Mixture Culture of Lactobacillus acidophilus LA-5 and Bifidobacterium bifidum 450B

The aim of this study was to evaluate the fermentation of dietary fiber from green bean (Phaseolus vulgaris) and prickly pear shell (Opuntia ficus-indica) by Lactobacillus acidophilus LA-5 and Bifidobacterium bifidum 450B growing as mono-culture and co-culture, the fermentation products, and proteins expressed during this process. The analysis of the fermentation profile showed a major growth of bacteria in the culture media of each dietary fiber supplemented with glucose, and particularly B. bifidum 450B at 48 h showed the highest growth. In the case of the co-culture, the growth was lower indicating the possible negative interaction between L. acidophilus LA-5 and B. bifidum 450B and may be due to the less amount of carbohydrates and the high content of non-soluble fiber that affected the nutrients availability for the bacterial strains. The pH changes indicated the presence of short-chain fatty acids (SCFAs), being acetate (46-100%) the main SCFA. Changes in the proteome concerned proteins that are involved in carbohydrate and other carbohydrate pathways. The characterization of the bacteria according to the growth, metabolites, and proteins expressed allows understanding the response to the change of environmental conditions and could be useful to understand L. acidophilus LA-5 and B. bifidum 450B strains' adaptation to specific applications.

Pb2+ Effects on Growth, Lipids, and Protein and DNA Profiles of the Thermophilic Bacterium Thermus Thermophilus

Extremophiles are organisms able to thrive in extreme environmental conditions and some of them show the ability to survive high doses of heavy metals thanks to defensive mechanisms provided by primary and secondary metabolic products, i.e., extremolytes, lipids, and extremozymes. This is why there is a growing scientific and industrial interest in the use of thermophilic bacteria in a host of tasks, from the environmental detoxification of heavy metal to industrial activities, such as bio-machining and bio-metallurgy. In this work Thermus thermophilus was challenged against increasing Pb²⁺ concentrations spanning from 0 to 300 ppm in order to ascertain the sensitiveness of this bacteria to the Pb environmental pollution and to give an insight on its heavy metal resistance mechanisms. Analysis of growth parameters, enzyme activities, protein profiles, and lipid membrane modifications were carried out. In addition, genotyping analysis of bacteria grown in the presence of Pb²⁺, using random amplified polymorphic DNA-PCR and DNA melting evaluation, were also performed. A better knowledge of the response of thermophilic bacteria to the different pollutants, as heavy metals, is necessary for optimizing their use in remediation or decontamination processes.

Shortening of the Lactobacillus paracasei subsp. paracasei BGNJ1-64 AggLb Protein Switches Its Activity from Auto-aggregation to Biofilm Formation

AggLb is the largest (318.6 kDa) aggregation-promoting protein of Lactobacillus paracasei subsp. paracasei BGNJ1-64 responsible for forming large cell aggregates, which causes auto-aggregation, collagen binding and pathogen exclusion in vitro. It contains an N-terminus leader peptide, followed by six successive collagen binding domains, 20 successive repeats (CnaB-like domains) and an LPXTG sorting signal at the C-terminus for cell wall anchoring. Experimental information about the roles of the domains of AggLb is currently unknown. To define the domain that confers cell aggregation and the key domains for interactions of specific affinity between AggLb and components of the extracellular matrix, we constructed a series of variants of the aggLb gene and expressed them in Lactococcus lactis subsp. lactis BGKP1-20 using a lactococcal promoter. All of the variants contained a leader peptide, an inter collagen binding-CnaB domain region (used to raise an anti-AggLb antibody), an anchor domain and a different number of collagen binding and CnaB-like domains. The role of the collagen binding repeats of the N-terminus in auto-aggregation and binding to collagen and fibronectin was confirmed. Deletion of the collagen binding repeats II, III, and IV resulted in a loss of the strong auto-aggregation, collagen and fibronectin binding abilities whereas the biofilm formation capability was increased. The strong auto-aggregation, collagen and fibronectin binding abilities of AggLb were negatively correlated to biofilm formation.

Exploring the relationship between exposure to technological and gastrointestinal stress and probiotic functional properties of lactobacilli and bifidobacteria

Strains of Lactobacillus and Bifidobacterium are considered probiotic because of their associated potential health benefits. Probiotics are commonly administered orally via incorporation into food products. Microorganisms for use as probiotics encounter stress conditions, which include acid, bile, osmotic, oxidative, heat and cold stresses. These can occur during processing and storage and during passage through the gastrointestinal tract, and can affect viability. Probiotic bacteria have to remain viable to confer any health benefits. Therefore, the ability to withstand technological and gastrointestinal stresses is crucial probiotic selection criteria. While the stress tolerance mechanisms of lactobacilli and bifidobacteria are largely understood, the impact of exposure to stressful conditions on the functional properties of surviving probiotic microorganisms is not clear. This review explores the potentially positive and negative relationships between exposure to stress conditions and probiotic functional properties, such as resistance to gastric acid and bile, adhesion and colonization potential, and tolerance to antibiotics. Protective strategies can be employed to combat negative effects of stress on functional properties. However, further research is needed to ascertain synergistic relationships between exposure to stress and probiotic properties.

Effects of milk components and food additives on survival of three bifidobacteria strains in fermented milk under simulated gastrointestinal tract conditions

Background

In the dairy industry, probiotic strains of Bifidobacterium are introduced into the composition of traditional starter cultures intended for the production of fermented foods, or sometimes are the sole microflora responsible for the fermentation process. In order to be able to reach the intestines alive and fulfil their beneficial role, probiotic strains must be able to withstand the acidity of the gastric juices and bile present in the duodenum.

Objective

The paper reports effects of selected fermented milk components on the viability of three strains of bifidobacteria in fermented milk during subsequent incubation under conditions representing model digestive juices.

Design

The viability of the bifidobacterial cells was examined after a 3-h incubation of fermented milk under simulated gastric juice conditions and then after 5-h incubation under simulated duodenum juice conditions. The Bifidobacterium strains tested differed in their sensitivity to the simulated conditions of the gastrointestinal juices.

Results

Bifidobacterial cell viability in simulated intestinal juices was dependent on the strain used in our experiments, and product components acted protectively towards bifidobacterial cells and its dose.

Conclusions

Bifidobacterial cells introduced into the human gastrointestinal tract as food ingredients have a good chance of survival during intestinal transit and to reach the large intestine thanks to the protective properties of the food components and depending on the strain and composition of the food.

The Effects of Lactobacillus acidophilus on the Intestinal Smooth Muscle Contraction through PKC/MLCK/MLC Signaling Pathway in TBI Mouse Model

Clinical studies have shown that probiotics influence gastrointestinal motility. However, the molecular mechanisms by which probiotic Lactobacillus modulates intestinal motility in traumatic brain injury (TBI) mouse model have not been explored. In the present study, we provided evidence showing that treatment of TBI mice with Lactobacillus acidophilus significantly improved the terminal ileum villus morphology, restored the impaired interstitial cells of Cajal (ICC) and the disrupted ICC networks after TBI, and prevented TBI-mediated inhibition of contractile activity in intestinal smooth muscle. Mechanistically, the decreased concentration of MLCK, phospho-MLC₂₀ and phospho-MYPT1 and increased concentration of MLCP and PKC were observed after TBI, and these events mediated by TBI were efficiently prevented by Lactobacillus acidophilus application. These findings may provide a novel mechanistic basis for the application of Lactobacillus acidophilus in the treatment of TBI.

Probiotics as cheater cells: parameter space clustering for individualized prescription

Clinicians often perform infection management administering probiotics along with antibiotics. Such probiotics added to an infecting population showing antibiotic resistance can be compared to a dynamical system composed of cheaters and workers. The presence of cheater strains is known to modulate the fitness of the infecting population. We propose a model where probiotics as cheater strain re-establishes the susceptibility of a resistant population towards an antibiotic. Control parameters must assume optimal values in order to attain minimum worker number within a finite time-scale feasible in a clinical set-up. The problem is made non-trivial by the complicated interplay between parameters. The model is an extension of a logistic framework, where a pay-off function has been included to account for the effect of instantaneous worker number on death rates of each species. The outcomes for a randomized set of parameter values and initial conditions are utilized in partitioning the set and desired clusters were identified. For a test case, one can take random combinations of controllable parameters and combine them with fixed parameters and find out the closeness of the points to the desired cluster centroids. This process leads to the identification of optimum antibiotic versus probiotic dosage range leading to elimination or limited existence of the genetically resistant population.

Eruca sativa might influence the growth, survival under simulated gastrointestinal conditions and some biological features of Lactobacillus acidophilus, Lactobacillus plantarum and Lactobacillus rhamnosus strains

The growth and viability of three Lactobacillus strains, Lactobacillus acidophilus, Lactobacillus plantarum and Lactobacillus rhamnosus, after their passage through simulated gastric and pancreatic juices were studied as a function of their presence in the growth medium of rocket salad (Eruca sativa). The presence of E. sativa affected some of the biological properties of the strains. For example, L. acidophilus and L. plantarum worked more efficiently in the presence of E. sativa, increasing not only the antioxidant activity of the medium, but also their own antioxidant power and antimicrobial activity; L. rhamnosus was not affected in the same manner. Overall, the presence of vegetables might help to boost, in specific cases, some of the characteristics of lactobacilli, including antioxidant and antimicrobial power.

Survival and synergistic growth of mixed cultures of bifidobacteria and lactobacilli combined with prebiotic oligosaccharides in a gastrointestinal tract simulator

BACKGROUND

Probiotics, especially in combination with non-digestible oligosaccharides, may balance the gut microflora while multistrain preparations may express an improved functionality over single strain cultures. In vitro gastrointestinal models enable to test survival and growth dynamics of mixed strain probiotics in a controlled, replicable manner.

METHODS

The robustness and compatibility of multistrain probiotics composed of bifidobacteria and lactobacilli combined with mixed prebiotics (galacto-, fructo- and xylo-oligosaccharides or galactooligosaccharides and soluble starch) were studied using a dynamic gastrointestinal tract simulator (GITS). The exposure to acid and bile of the upper gastrointestinal tract was followed by dilution with a continuous decrease of the dilution rate (de-celerostat) to simulate the descending nutrient availability of the large intestine. The bacterial numbers and metabolic products were analyzed and the growth parameters determined.

RESULTS

The most acid- and bile-resistant strains were Lactobacillus plantarum F44 and L. paracasei F8. Bifidobacterium breve 46 had the highest specific growth rate and, although sensitive to bile exposure, recovered during the dilution phase in most experiments. B. breve 46, L. plantarum F44, and L. paracasei F8 were selected as the most promising strains for further studies.

CONCLUSIONS

De-celerostat cultivation can be applied to study the mixed bacterial cultures under defined conditions of decreasing nutrient availability to select a compatible set of strains.

Effect of prebiotic carbohydrates on growth, bile survival and cholesterol uptake abilities of dairy-related bacteria

BACKGROUND

Three strains of lactic acid bacteria and one probiotic Bifidobacterium strain sourced from milk origin were considered to select for the best synbiotic-like combination for cholesterol uptake ability. For that purpose, fermentative characteristics, bile salt hydrolase activity, bile survival and cholesterol removal were assessed in the presence of different carbohydrates.

RESULTS

Carbohydrate fermentability was highly variable among the different strains, and lactulose was the only prebiotic to favour growth of all strains, whereas pectin led to low population regardless of the strain. Bile survival of bacteria could be improved by the preferred carbon source and was related to their bile salt hydrolase activities. All together, our results showed that the most advantageous synbiotic-like combinations to achieve cholesterol uptake abilities were Lactobacillus delbrueckii subsp. bulgaricus LB 340 with raffinose, Streptococcus thermophilus TA040 or Lactobacillus rhamnosus LBRE-LSAS with lactulose, and Bifidobacterium animalis subsp. lactis Bb12 with mannitol.

CONCLUSION

The suggested synbiotics may represent new promising functional dairy additives.

Superior prebiotic and physicochemical properties of novel dextran from Weissella cibaria JAG8 for potential food applications

The dextran fromWeissella cibariaJAG8 showed good water holding capacity, emulsion, and flocculation activity. Dextran displayed greater thermal stability, resistance to hydrolysis by simulated gastric juice and α-amylase and promoted the growth of probiotic bacteria.

Probiotics, prebiotics, synbiotics in prevention and treatment of inflammatory bowel diseases

Probiotics, prebiotics, and synbiotics are functional components able to exert positive effects on human health. Numerous medical conditions lack effective and safe approaches for prevention or treatment, thus usage of probiotics, prebiotics, and synbiotics is an alternative. Further, the benefit related to the consumption of these compounds is associated with lower morbidity of chronic diseases and reduced health-care costs. Various types of mediums to deliver probiotics/synbiotics to the human GIT are used. Although capsules and tablets are frequently applied as delivery systems for probiotics, the major challenge of the commercial sector is to market new functional foods containing probiotics and/or prebiotics. Discovering of new probiotic/synbiotic functional foods is connected to the interest of the food industry to revitalize continuously through introduction of products with improved nutritional value and pleasant taste, but also with health benefit for the consumers. The review provides insights and new perspectives in respect to usage of functional components and foods in prevention and treatment of inflammatory bowel diseases (IBD) that are highly correlated with the modern lifestyle. The therapeutic and safety properties of probiotics and prebiotics, their role in pathogenesis of IBD, potential to prevent and treat these diseases as well as postulated mechanisms of action will be discussed, highlighting the main areas in which further research is an emergence.

Protein analysis-on-chip systems in foodomics

Protein compositional data can address nutritional, packaging, origin/authenticity, processing history, safety and other quality questions. Such data has been time-consuming and expensive to generate until recently but “protein analysis on a chip” systems are now available that can analyze a complex food sample in a few minutes and do not require great protein analytical expertise. We review some of the main new approaches with examples of their application and discuss their advantages and disadvantages.