Molecular characterization of gluten hydrolysing Bacillus sp. and their efficacy and biotherapeutic potential as probiotics using Caco-2 cell line

Association of intestinal dysbiosis with susceptibility to multiple sclerosis: Evidence from different population studies (Review)

Understanding the relationship between microorganisms that live in our intestines and neuroinflammatory and neurodegenerative pathologies of the central nervous system (CNS) is essential, since they have been shown to have an immunomodulatory effect in neurological disorders, such as multiple sclerosis (MS). The gut microbiota can be affected by several environmental factors, including infections, physical and emotional stress and diet, the latter known as the main modulator of intestinal bacteria. An abrupt shift in the gut microbiota composition and function is known as dysbiosis, a state of local and systemic inflammation produced by pathogenic bacteria and its metabolites responsible for numerous neurological symptoms. It may also trigger neuronal damage in patients diagnosed with MS. Intestinal dysbiosis affects the permeability of the intestine, allowing chronic low-grade bacterial translocation from the intestine to the circulation, which may overstimulate immune cells and cells resident in the CNS, break immune tolerance and, in addition, alter the permeability of the blood-brain barrier (BBB). This way, toxins, inflammatory molecules and oxidative stress molecules can pass freely into the CNS and cause extensive damage to the brain. However, commensal bacteria, such as the Lactobacillus genus and Bacteroides fragilis, and their metabolites (with anti-inflammatory potential), produce neurotransmitters such as γ-aminobutyric acid, histamine, dopamine, norepinephrine, acetylcholine and serotonin, which are important for neurological regulation. In addition, reprogramming the gut microbiota of patients with MS with a healthy gut microbiota may help improve the integrity of the gut and BBB, by providing clinically protective anti-inflammatory effects and reducing the disease's degenerative progression. The present review provides valuable information about the relationship between gut microbiota and neuroinflammatory processes of the CNS. Most importantly, it highlights the importance of intestinal bacteria as an environmental factor that may mediate the clinical course of MS, or even predispose to the outbreak of this disease.

Assessing the probiotic potential, antioxidant, and antibacterial activities of oat and soy milk fermented with Lactiplantibacillus plantarum strains isolated from Tibetan Kefir

Sufficient intake of probiotics has been shown to help in the digestion, protect the body against pathogenic microorganisms and boost the immune system. Recently, due to high prevalence of milk allergies and lactose intolerance in population, the non-dairy based probiotic alternative are becoming increasing popular. In this context, the oat milk and soya milk-based fermented products can be an ideal alternative for the development of Lactic acid bacteria bacteria based probiotics. These bacteria can not only improve the product's flavor and bioavailability but also increases its antibacterial and antioxidant capabilities due to fermentation process. The purpose of the resent work was to assess the antioxidant and probiotic properties of oat and soy milk that had been fermented with three different strains of Lactiplantibacillus plantarum (L. plantarum) including L. plantarum 12-3, L. plantarum K25, and L. plantarum YW11 isolated from Tibetan Kefir. Different validated assays were used to evaluate the probiotic properties, adhesion and survival in the digestive system (stomach, acid and bile salts resistance), antioxidant and antimicrobial activities and safety (ABTS and DPPH scavenging assays) of these strains. Results of the study showed that soya milk and oat milk fermented with L. plantarum strains possess promising probiotic, antibacterial and antioxidant properties. These results can be helpful to produce dairy-free probiotic replacements, which are beneficial for those who are unable to consume dairy products due to dietary or allergic restrictions.

Evaluating the Probiotic Potential of Lactic Acid Bacteria Implicated in Natural Fermentation of Table Olives, cv. Cobrançosa

The probiotic features of Lactiplantibacillus (L.) pentosus and L. paraplantarum strains, endogenous in Cobrançosa table olives from northeast Portugal, were assessed in terms of functional properties and health benefits. Fourteen lactic acid bacteria strains were compared with Lacticaseibacillus casei from a commercial brand of probiotic yoghurt and L. pentosus B281 from Greek probiotic table olives, in attempts to select strains with higher probiotic performances than those references. For functional properties, the i53 and i106 strains, respectively, exhibited: 22.2 ± 2.2% and 23.0 ± 2.2% for Caco-2 cell adhesion capacity; 21.6 ± 7.8% and 21.5 ± 1.4% for hydrophobicity; 93.0 ± 3.0% and 88.5 ± 4.5% for autoaggregation ability by 24 h of incubation; and ability to co-aggregate with selected pathogens-from 29 to 40% to Gram+ (e.g., Staphylococcus aureus ATCC 25923 and Enterococcus faecalis ATCC 29212); and from 16 to 44% for Gram- (e.g., Escherichia coli ATCC 25922 and Salmonella enteritidis ATCC 25928). The strains proved to be resistant (i.e., halo zone ≤14 mm) to some antibiotics (e.g., vancomycin, ofloxacin, and streptomycin), but susceptible (i.e., halo zone ≥ 20 mm) to others (e.g., ampicillin and cephalothin). The strains exhibited health-beneficial enzymatic activity (such as acid phosphatase and naphthol-AS-BI-phosphohydrolase), but not health-harmful enzymatic activity (such as β-glucuronidase and N-acetyl-β-glucosaminidase). Additionally, the antioxidant activity and cholesterol assimilation features, respectively, of the strains were 19.6 ± 2.8% and 77.5 ± 0.5% for i53, and 19.6 ± 1.8% and 72.2 ± 0.9% for i106. This study indicated that the addition of L. pentosus strains i53 and/or i106 to Cobrançosa table olives is likely to enhance the added value of the final product, in view of the associated potential benefits upon human health.

Probiotic with gluten reduction property and its encapsulation in synbiotic aloe vera gel-alginate capsules with banana powder as prebiotic

This study aims to hydrolyze the immunogenic gluten peptides by probiotic bacteria, Lactococcus lactis G01. It was isolated from curd and isolation was done based on ability to hydrolyze gluten. It was also tested for probiotic properties such as survival in gastric juice, bile salts, acid resistance, antibiotic sensitivity, antioxidant potential, sodium chloride tolerance, and antimicrobial activity. Lactococcus lactis G01 exhibited potential probiotic properties also, hence it was selected for microencapsulation. Probiotic was encapsulated in sodium alginate beads using banana powder as prebiotic and aloe vera as the adsorbent. The bead morphology was studied using scanning electron microscopy and transmission electron microscopy. The chemical composition of the bead was confirmed by FTIR. It was observed that 99% of the encapsulated probiotic cells were released into the simulated intestinal fluid in 90 min. Storage study was conducted for encapsulated probiotic and after four weeks of storage, the probiotic count in microcapsules was 7.82 log10 CFU/g. The formulated synbiotic capsules are suggested to incorporate in porridge for celiac patients since the probiotic has gluten reduction property.

Graphical abstract

Probiotic potential of β‑galactosidase‑producing lactic acid bacteria from fermented milk and their molecular characterization

Probiotics have attained significant interest in recent years as a result of their gut microbiome modulation and gastrointestinal health benefits. Numerous fermented foods contain lactic acid bacteria (LAB) which are considered as GRAS and probiotic bacteria. The present study aimed to investigate indigenous LAB from homemade fermented milk samples collected in remote areas of Karnataka (India), in order to isolate the most potent and well-adapted to local environmental conditions bacteria, which were then evaluated using a step-by-step approach focused on the evaluation of probiotic traits and β-galactosidase-producing ability. LAB were screened using 5-bromo-4-chloro-3-indole-D-galactopyranoside (X-Gal) and O-nitrophenyl-β-D-galactopyranoside (ONPG) as substrate, and exhibited β-galactosidase activity ranging from 728.25 to 1,203.32 Miller units. The most promising isolates were selected for 16S rRNA gene sequence analysis and identified as Lactiplantibacillus plantarum, Limosilactobacillus fermentum, Lactiplantibacillus pentosus and Lactiplantibacillus sp. Furthermore, these isolates were evaluated by in vitro, viz., survival in gastrointestinal tract, antibiotic susceptibility, antimicrobial activity, cell surface characteristics, and haemolytic activity. All eight isolates demonstrated strong adherence and prevented pathogen penetration into HT-29 cells, indicating potential of the bacteria to scale up industrial level production of milk products for lactose intolerants.

Gluten Degradation by the Gut Microbiota of Ulcerative Colitis Patients

Several studies have reported improved disease symptomatology in ulcerative colitis (UC) patients consuming a gluten free diet. This observation coupled with diversity depletion in the gut microbiota of UC patients led us to hypothesize that UC-associated enteric microbes differentially metabolize dietary gluten to produce immunogenic products that promote inflammation. Gluten concentration in stool was determined using gluten-specific ELISA, and gluten intake was assessed by food frequency questionnaire (FFQ) in UC (n = 12) and healthy controls (HC; n = 13). Gluten-metabolizing bacteria were isolated on minimal media supplemented with 1% gluten from UC and HC and identified by 16S rRNA profiling. Cell-free culture media from gluten metabolizing gut bacterial isolates was assessed for immunogenicity in vitro using HT29 colonocytes. Compared to HC, UC patients did not consume gluten differently (Mann−Whitney; p > 0.10) and exhibited equivalent levels of gluten in their feces (Mann−Whitney; p = 0.163). The profile of gluten-degrading bacteria isolated from UC stool was distinct (Chi-square; p ≤ 0.0001). Compared with Enterococcus isolates, products of gluten degradation by Bacillus strains induced higher IL8 and lower occludin (Mann−Whitney; p = 0.002 and p = 0.059, respectively) gene expression in colonocytes irrespective of whether they originated from UC or healthy gut. Members of HC and UC microbiota exhibit gluten-degrading ability, metabolites of which influence genes involved in inflammation and barrier function in enteric colonocyte cultures. Preliminary findings of this study warrant further investigations into the mechanisms by which gut microbiota contribute to UC pathogenesis through gluten degradation.

Screening of Spore-Forming Bacteria with Probiotic Potential in Pristine Algerian Caves

The interest and exploration of biodiversity in subsurface ecosystems have increased significantly during the last 2 decades. The aim of this study was to investigate the in vitro probiotic properties of spore-forming bacteria isolated from deep caves. Two hundred fifty spore-forming microbes were enriched from sediment samples from 10 different pristine caves in Algeria at different depths. Isolates showing nonpathogenic profiles were screened for their potential to produce digestive enzymes (gliadinase and beta-galactosidase) in solid and liquid media, respectively. Different probiotic potentialities were studied, including (i) growth at 37°C, (ii) survival in simulated gastric juice, (iii) survival in simulated intestinal fluid, and (iv) antibiotic sensitivity and cell surface properties. The results showed that out of 250 isolates, 13 isolates demonstrated nonpathogenic character, probiotic potentialities, and ability to hydrolyze gliadin and lactose in solution. These findings suggest that a selection of cave microbes might serve as a source of interesting candidates for probiotics.

IMPORTANCE Previous microbial studies of subsurface ecosystems like caves focused mainly on the natural biodiversity in these systems. So far, only a few studies focused on the biotechnological potential of microbes in these systems, focusing in particular on their antibacterial potential, antibiotic production, and, to some extent, enzymatic potential. This study explores whether subsurface ecosystems can serve as an alternative source for microbes relevant to probiotics. The research focused on the ability of cave microbes to degrade two substrates (lactose and gliadin) that cause common digestive disorders. Since these enzymes may prove to be useful in food processing and in reducing the effect of lactose and gliadin digestion within intolerant patients, isolation of microbes such as in this study may expand the possibilities of developing alternative strategies to deal with these intolerances.

Purified Clinoptilolite-Tuff as an Efficient Sorbent for Gluten Derived from Food

Various gluten-related diseases (celiac disease, wheat allergy, gluten sensitivity) are known and their incidence is growing. Gluten is a specific type of plant storage protein that can impair the health of gluten-prone persons following consumption, depending on the origin. The most severe effects are induced by wheat, barley, and rye. The only treatment is based on the absolute avoidance of those foods, as even traces might have severe effects on human well-being. With the goal of binding gluten impurities after ingestion, an in vitro setting was created. A special processed kind of zeolite, purified clinoptilolite-tuff (PCT), was implemented as an adsorber of gluten derived from different origins. Zeolites are known for their excellent sorption capacities and their applications in humans and animals have been studied for a long time. Tests were also performed in artificial gastric and intestinal fluids, and the adsorption capacity was determined via a certified validated method (ELISA). Depending on the kind of gluten source, 80–130 µg/mg of gluten were bound onto PCT. Hence, purified clinoptilolite-tuff, which was successfully tested for wheat, barley, and rye, proved to be suitable for the adsorption of gluten originating from different kinds of crops. This result might form the basis for an expedient human study in the future.

Effects of Lactococcus lactis subsp. cremoris YRC3780 daily intake on the HPA axis response to acute psychological stress in healthy Japanese men

BACKGROUND

Lactococcus lactis subsp. cremoris (YRC3780), which is isolated from kefir, has been associated with anti-allergic effects in humans. However, it remains unknown whether daily intake of YRC3780 attenuates the response to psychological stress in humans in parallel with changes to the gut microbiome. We examined the fundamental role of YRC3780 in the gut microbiome, stress response, sleep, and mental health in humans.

METHODS

Effects of daily intake of YRC3780 on the hypothalamic-pituitary-adrenal (HPA) axis response to acute psychological stress were investigated in a double-blind, placebo-controlled clinical trial involving 27 healthy young men (mean age and body mass index: 23.5 years and 21.5 kg/m²) who were randomly assigned to placebo (n = 13) or YRC3780 (n = 14) groups. The HPA axis response to acute psychological stress, the diurnal rhythm of HPA axis activity, and gut microbiome were assessed and compared between the two groups.

RESULTS

The results showed that daily intake of YRC3780 significantly lowered morning salivary cortisol levels compared with placebo. In addition, salivary cortisol levels following a social stress test significantly decreased +40 min after beginning the TSST in the YRC3780-treated group compared to placebo. There were no significant differences between the two groups in terms of actigraphy-based sleep quality, but the subjective sleep quality and mental health were significantly improved in the YRC3780-treated group compared to placebo.

CONCLUSIONS

Our study suggests that daily intake of YRC3780 improves the HPA axis response to acute psychological stress, which might be associated with a decrease in morning cortisol levels.

Characterization of Novel Lactobacillus fermentum from Curd Samples of Indigenous Cows from Malnad Region, Karnataka, for their Aflatoxin B1 Binding and Probiotic Properties

Thirty-four isolates of Lactobacillus spp. (LAB) from 34 curd samples were evaluated for their aflatoxin B₁ (AFB₁) binding and probiotic properties. Upon characterization, four LAB isolates (LC3/a, LC4/c, LC/5a, and LM13/b) were found to be effective in removing AFB₁ from culture media with a capacity of above 75%. Staining reaction, biochemical tests, pattern of sugar utilization, and 16s rRNA gene sequence analysis revealed the identity of all the four isolates as L. fermentum. All of them could tolerate acidic pH, salt, and bile, which promise the use of these probiotic bacterial isolates for human applications. These isolates showed poor hydrophobicity and higher auto-aggregation properties. All L. fermentum isolates were found susceptible to gentamycin, chloramphenicol, cefoperazone, ampicillin, and resistant to ciprofloxacin and vancomycin. Results of hemolytic and DNase activity indicated their nonpathogenic nature. Though all L. fermentum isolates found inhibiting the growth of Salmonella ebony, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, maximum inhibition was obtained with isolate LC5/a. Kinetic studies revealed that all four bacteria required a minimum of 2 h to reach stationary phase of AFB₁ binding. AFB₁ binding ability varied from 66 to 85.2% among these four isolates. Bile (0.4%) was significant (P ≤ 0.05) in reducing the AFB₁ binding property of isolates LC3/a, LC4/c, and LM13/b, while increased AFB₁ binding ability was recorded at acidic pH (2.0). AFB₁ binding properties of isolate LC5/a were found least affected by acidic pH and bile. The findings of our study revealed the higher efficiency of L. fermentum isolate LC5/a in reducing the bioavailability of AFB1 in gut, and additionally, it improves the consumers' health by its various probiotic characters. These beneficial characters, L. fermentum isolates, promise them to use as probiotic formulations alone or in combinations with other beneficial probiotic-bacterial isolates.

Gluten hydrolyzing activity of Bacillus spp isolated from sourdough

BACKGROUND

Celiac disease is an intestinal chronic disorder with multifactorial etiology resulting in small intestinal mucosal injuries and malabsorption. In genetically predisposed individuals with HLA DQ2/DQ8 molecules, the gluten domains rich in glutamine and proline present gluten domains to gluten reactive CD4+ T cells causing injury to the intestine. In the present experimental design, the indigenous bacteria from wheat samples were studied for their gluten hydrolyzing functionality.

RESULTS

Proteolytic activity of Bacillus spp. was confirmed spectrophotometrically and studied extensively on gliadin-derived synthetic enzymatic substrates, natural gliadin mixture, and synthetic highly immunogenic 33-mer peptide. The degradation of 33-mer peptide and the cleavage specificities of the selected isolates were analyzed by tandem mass spectrometry. The gluten content of the sourdough fermented by the chosen bacterial isolates was determined by R5 antibody based competitive ELISA. All the tested isolates efficiently hydrolyzed Z-YPQ-pNA, Z-QQP-pNA, Z-PPF-pNA, and Z-PFP-pNA and also cleaved 33-mer immunogenic peptide extensively. The gluten content of wheat sourdough was found to be below 110 mg/kg.

CONCLUSION

It has been inferred that four Bacillus spp especially GS 188 could be useful in developing gluten-reduced wheat food product for celiac disease prone individuals.

Surface components and metabolites of probiotics for regulation of intestinal epithelial barrier

The gut microbiota can significantly affect the function of the intestinal barrier. Some intestinal probiotics (such as Lactobacillus, Bifidobacteria, a few Escherichia coli strains, and a new generation of probiotics including Bacteroides thetaiotaomicron and Akkermansia muciniphila) can maintain intestinal epithelial homeostasis and promote health. This review first summarizes probiotics' regulation of the intestinal epithelium via their surface compounds. Surface layer proteins, flagella, pili and capsular polysaccharides constitute microbial-associated molecular patterns and specifically bind to pattern recognition receptors, which can regulate signaling pathways to produce cytokines or inhibit apoptosis, thereby attenuating inflammation and enhancing the function of the gut epithelium. The review also explains the effects of metabolites (such as secreted proteins, organic acids, indole, extracellular vesicles and bacteriocins) of probiotics on host receptors and the mechanisms by which these metabolites regulate gut epithelial barrier function. Previous reviews summarized the role of the surface macromolecules or metabolites of gut microbes (including both probiotics and pathogens) in human health. However, these reviews were mostly focused on the interactions between these substances and the intestinal mucosal immune system. In the current review, we only focused on probiotics and discussed the molecular interaction between these bacteria and the gut epithelial barrier.

Draft Genome Sequence of the Gluten-Hydrolyzing Bacterium Bacillus subtilis GS 188, Isolated from Wheat Sourdough

The draft genome sequence of Bacillus subtilis GS 188, a novel spore-forming probiotic bacterium with gluten-hydrolyzing potential, was isolated from wheat sourdough and provides deep insights into the beneficial features of this strain for its use in the preparation of gluten-reduced wheat foods for humans with celiac disease.