Assessment of the safety of Levilactobacillus brevis CNCM I-5321, a probiotic candidate strain isolated from pulque with anti-proliferative activities

Gut dysbiosis has been strongly correlated with colorectal cancer (CRC) development and the use of probiotics to modulate this imbalance represents a potential and promising therapy to prevent and treat CRC. For this reason, the identification of novel probiotic strains from diverse origins has widely increased in recent years, including traditional fermented foods. In this work we describe a new strain previously isolated from pulque (a traditional Mexican beverage), Levilactobacillus brevis CNCM I-5321, which may represent an interesting probiotic candidate to prevent and treat cancer. Indeed, our results show that CNCM I-5321 displays significant and specific antiproliferative capacities in human intestinal cancer cell lines (HT-29, HTC-116 and Caco-2 cells), but not in normal cells (FH cells). In addition, CNCM I-5321 is able to induce: (1) a pro-inflammatory immune response through stimulation of interleukin (IL)-2, IL-6, IL-12 and IL-17 cytokines and (2) apoptosis via activation of caspase 8. On the other hand, a minimum inhibitory concentration (MIC) assay revealed phenotypic resistance of this strain to ampicillin and chloramphenicol. However, no known transferable determinants were found in the genome of CNCM I-5321, thus this probiotic candidate presents no risk of horizontal transfer to the intestinal bacterial population. Finally, the safety status of CNCM I-5321 was evaluated using an innovative model of chicken embryo chorioallantoic membrane (CAM) to assess undesirable and/or toxic effects. Overall, our results support that CNCM I-5321 strain is non-pathogenic and safe for potential use as an anti-cancer candidate in human and animal medicine.

Evaluation of probiotic properties of Levilactobacillus brevis isolated from hawthorn vinegar

Probiotic microorganisms are increasing their interest today due to the benefits they provide to humans. Vinegar is the process of processing foods containing carbohydrates that can be fermented by acetic acid bacteria and yeasts. Hawthorn vinegar is also important in terms of amino acids, aromatic compounds, organic acids, vitamins and minerals it contains. Depending on the variety of microorganisms in it, the content of hawthorn vinegar changes, especially its biological activity. Bacteria were isolated from handmade hawthorn vinegar obtained in this study. After performing its genotypic characterization, it has been tested that it can grow in low pH environment, survive in artificial gastric and small intestinal fluid, survive against bile acids, surface adhesion characteristics, antibiotic susceptibility, adhesion, and degrade various cholesterol precursors. According to the results obtained, the studied isolate is Levilactobacillus brevis, it can reproduce best at pH 6.3, survives 72.22% in simulated gastric juice, 69.59% in small intestinal fluid, and 97% adhesion to HTC-116. Partially reproduces even in the presence of 2% ox-bile, surface hydrophobicity is 46.29% for n-hexadecane. It has been determined that it can degrade 4 different cholesterol precursors except for Sodium thioglycolate and is generally resistant to antibiotics except for CN30 and N30. Considering the experimental findings of Levilactobacillus brevis isolated from hawthorn vinegar for the first time, it can be said that Levilactobacillus brevis has probiotic properties.

Characterization of a Lactobacillus brevis strain with potential oral probiotic properties

BACKGROUND

The microflora composition of the oral cavity affects oral health. Some strains of commensal bacteria confer probiotic benefits to the host. Lactobacillus is one of the main probiotic genera that has been used to treat oral infections. The objective of this study was to select lactobacilli with a spectrum of probiotic properties and investigate their potential roles in oral health.

RESULTS

An oral isolate characterized as Lactobacillus brevis BBE-Y52 exhibited antimicrobial activities against Streptococcus mutans, a bacterial species that causes dental caries and tooth decay, and secreted antimicrobial compounds such as hydrogen peroxide and lactic acid. Compared to other bacteria, L. brevis BBE-Y52 was a weak acid producer. Further studies showed that this strain had the capacity to adhere to oral epithelial cells. Co-incubation of L. brevis BBE-Y52 with S. mutans ATCC 25175 increased the IL-10-to-IL-12p70 ratio in peripheral blood mononuclear cells, which indicated that L. brevis BBE-Y52 could alleviate inflammation and might confer benefits to host health by modulating the immune system.

CONCLUSIONS

L. brevis BBE-Y52 exhibited a spectrum of probiotic properties, which may facilitate its applications in oral care products.

Probiotic and antioxidant properties of selenium-enriched Lactobacillus brevis LSe isolated from an Iranian traditional dairy product

The present study was designed to isolate a highly selenium-tolerant lactobacillus strain from an Iranian traditional dairy product named as Spar. Different criteria such as tolerance to the low pH, simulated gastric juice (SGJ), simulated intestinal juice (SIJ) and bile salts tolerance as well as Caco-2 cell adhesion assay were examined to evaluate the probiotic potentials of the selected isolate. Furthermore, the antioxidant properties of the isolate cultivated in medium containing and free of SeO₃^2- ions were evaluated using DPPH scavenging and reducing power assays. The isolate was identified using conventional identification and 16S rDNA gene sequencing methods as Lactobacillus brevis LSe. The obtained results showed that the isolate was able to tolerate high concentration of sodium selenite (3.16mM). By decreasing the pH of the SGJ from 6 to 3, the survival percent of L. brevis LSe was not significantly changed over the time (p>0.05). In addition, the survival percent of the isolate in the SIJ (pH 6 and pH 8) was not statistically altered after 3h, 6h and 24h of incubation (p>0.05). In the presence of bile salts (0.3% and 0.6%) the survival rate of L. brevis LSe was not significantly decreased (p>0.05).L. brevis LSe also demonstrated the satisfactory ability to adhere to Caco-2 cells which were similar to that of the reference strain L. plantarum. The obtained results of antioxidant evaluation showed that L. brevis LSe containing elemental Se exhibited significantly higher radical scavenging ability (36.5±1.31%) and reducing power (OD₇₀₀, 0.14) than L. brevis LSe cultured in selenite-free medium (p<0.05). To sum up, further investigations should be conducted to merit the probable potential health benefit of Se-enriched L. brevis LSe and its application as Se-containing supplements or fermented foods.

Biological valorization of pure and crude glycerol into 1,3-propanediol using a novel isolate Lactobacillus brevis N1E9.3.3

The aim of the study was to evaluate a novel onsite enrichment approach to isolate a crude glycerol utilizing facultative anaerobic bacteria. An onsite enrichment in natural conditions resulted an isolate, Lactobacillus brevis N1E9.3.3, that can utilize glycerol and produce 1,3-propanediol with a yield of 0.89g1,3-PDO/gGlycerol and productivity of 0.78g1,3-PDO/l/h at pH-8.5 under anaerobic conditions. Batch fermentation experiments with glycerol-glucose co-fermentation strategy was carried out to evaluate the production of 1,3-propanediol and other byproducts. The effect of other carbon sources as co-substrate was also evaluated. At the optimized condition, 18.6g/l 1,3-propanediol was monitored when biodiesel industry generated crude glycerol and 2.5% glucose were used as the substrate.

Lactobacillus brevis OPK-3 isolated from kimchi inhibits adipogenesis and exerts anti-inflammation in 3T3-L1 adipocyte

BACKGROUND

Kimchi is a traditional fermented food in Korea that contains various unique microorganisms. Diverse bacteria are involved in the process of Kimchi fermentation and the healthful advantages; one of the major species is Lactobacillus. We investigated whether lactic acid bacteria isolated from Kimchi (KLAB) are capable of reducing intracellular lipid accumulation by downregulating the expression of adipogenesis and lipogenesis promoting genes in differentiating 3T3-L1 cells.

RESULTS

KLAB (Lactobacillus brevis OPK-3) mediated dose-dependent inhibition of adipocyte differentiation, intracellular triglyceride accumulation and glycerol-3-phosphate dehydrogenase (GPDH) activity. The expression of transcription factors such as peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding protein α involved in adipogenesis was markedly decreased by the KLAB treatment. Terminal adipogenic marker, e.g. adipocyte fatty acid binding protein (aP2), lipoprotein lipase, liver X receptor α, leptin and GPDH were significantly downregulated by KLAB treatment compared to untreated control. Moreover, cytokine genes, such as tumor necrosis factor-α and interleukin-6 mRNA expressions level were also decreased, whereas adiponectin mRNA level was upregulated by KLAB.

CONCLUSION

These results suggest that the KLAB inhibits lipid accumulation in the differentiating adipocyte through downregulating the expression of adipogenic transcription factors and other specific genes involved in lipid metabolism.

Biodiversity of Lactobacillus plantarum from traditional Italian wines

In this study, 23 samples of traditional wines produced in Southern Italy were subjected to microbiological analyses with the aim to identify and biotype the predominant species of lactic acid bacilli. For this purpose, a multiple approach, consisting in the application of both phenotypic (API 50CHL test) and biomolecular methods (polymerase chain reaction-denaturing gradient gel electrophoresis and 16S rRNA gene sequencing) was used. The results showed that Lactobacillus plantarum was the predominant species, whereas Lb. brevis was detected in lower amount. In detail, out of 80 isolates 58 were ascribable to Lb. plantarum and 22 to Lb. brevis. Randomly amplified polymorphic DNA-polymerase chain reaction was used to highlight intraspecific variability among Lb. plantarum strains. Interestingly, the cluster analysis evidenced a relationship between different biotypes of Lb. plantarum and their origin, in terms of wine variety. Data acquired in this work show the possibility to obtain several malolactic fermentation starter cultures, composed by different Lb. plantarum biotypes, for their proper use in winemaking processes which are distinctive for each wine.

Lactobacillus brevis strains from fermented aloe vera survive gastroduodenal environment and suppress common food borne enteropathogens

Five novel Lactobacillus brevis strains were isolated from naturally fermented Aloe vera leaf flesh. Each strain was identified by Random Amplified Polymorphic DNA (RAPD) analysis and 16S rRNA sequence comparison. These strains were highly tolerant to acid, surviving in pH2.5 for up to 4 hours, and resistant to 5% bile salts at 37°C for 18 hours. Due to its tolerance to acid and bile salts, one strain passed through the gastric barrier and colonised the intestine after oral administration. All five strains inhibited the growth of many harmful enteropathogens without restraining most of normal commensals in the gut and hence named POAL (Probiotics Originating from Aloe Leaf) strains. Additionally, each strain exhibited discriminative resistance to a wide range of antibiotics. The L. brevis POAL strains, moreover, expressed high levels of the glutamate decarboxylase (GAD) gene which produces a beneficial neurotransmitter, γ-aminobutyric acid (GABA). These characteristics in all suggest that the novel L. brevis strains should be considered as potential food additives and resources for pharmaceutical research.

Effect of Lactobacillus brevis 119-2 isolated from Tsuda kabu red turnips on cholesterol levels in cholesterol-administered rats

In a previous in vitro study, we reported that the potential mechanism of the cholesterol-lowering effect of Lactobacillus brevis 119-2 isolated from turnip Tsuda kabu was the incorporation of cholesterol to cell membrane. In this study, we analyzed serum cholesterol and hepatic gene expression of Sprague-Dawley (SD) rats kept on a cholesterol diet with or without L. brevis 119-2 for 2 weeks, to evaluate the cholesterol-lowering effect in vivo. Serum cholesterol levels were significantly reduced in SD rats kept on a diet including L. brevis 119-2 compared with that in SD rats kept on a diet without L. brevis 119-2, and both viable and dead L. brevis 119-2 induced this effect. Hepatic gene analysis by DNA microarray suggested that the potential mechanism of the cholesterol-lowering effect of L. brevis 119-2 in vivo was inhibition of 3-hydroxy-3-methylglutaryl-CoA reductase activity by insulin induced gene (Insig) protein, and induction of catabolism of cholesterol to bile acid by Cyp7a1 (cytochrome P450 a1). In addition, we found that inclusion of L. brevis 119-2 in the diet decreased serum low density lipoprotein (LDL) cholesterol levels by inducing overexpression of the LDL receptor gene. In contrast, Lactobacillus acidophilus ATCC 43121 increased high density lipoprotein cholesterol levels by inducing overexpression of the ATP-binding cassette sub-family. A member 1 (Abca1) and Angiopoietin-like 3 (Angptl3) genes. These results suggest that L. brevis 119-2 decreases the risk of atherosclerosis by lowering serum cholesterol, ameliorating the effect of fatty liver.

Fructophilic Lactobacillus kunkeei and Lactobacillus brevis isolated from fresh flowers, bees and bee-hives

Two-hundred-and-thirty-six isolates were collected from fresh flowers, bees and bee-hives. Of these, 20 isolates preferred D-fructose as carbon source, produced lactic acid and acetic acid but trace amounts of ethanol and were classified as fructophilic. Poor growth was recorded when strains were incubated anaerobically in the presence of D-glucose as sole carbon source. Good growth was, however, recorded when D-glucose was metabolized in the presence of external electron acceptors such as fructose, pyruvate and oxygen. Nineteen of the strains were classified as Lactobacillus kunkeei and one as Lactobacillus brevis based on phenotypic characteristics, 16S rRNA sequences, recA sequences and DNA homology. This is the first description of a fructophilic strain of L. brevis.

Dynamics of indigenous lactic acid bacteria populations in wine fermentations from La Rioja (Spain) during three vintages

Diversity of lactic acid bacteria (LAB) species has been analyzed for three consecutive years (2006, 2007, and 2008) during alcoholic and malolactic fermentations of Tempranillo wine in a winery at La Rioja. The results showed differences in malolactic fermentation duration, and in both diversity of LAB species and diversity of Oenococcus oeni genotypes. O. oeni was shown to be the predominant species (73% of total isolates). Monitoring the different strains of O. oeni using pulsed-field gel electrophoresis of chromosomal DNA digested with SfiI and ApaI allowed detection of a total of 37 distinct genotypes, most of them comprised at least two isolates. Six appeared in more than one vintage, one of them being present in the three studied years. Moreover, four genotypes were indistinct of the strains isolated from the air of this same winery in 2007 vintage. The frequency of participation of each genotype varied from year to year, thus dominant genotypes at one year were minority or not present at another year. This suggests that distinct indigenous O. oeni strains are better adapted to the different winery conditions every year. Predominant genotypes that appeared in more than one vintage and lead to quality wines with low histamine contents could be considered as interesting for selecting of new malolactic starter cultures.

Efficacy of recA gene sequence analysis in the identification and discrimination of Lactobacillus hilgardii strains isolated from stuck wine fermentations

Conventional phenotypic methods sometimes lead to misidentification of some heterofermentative wine lactobacilli such as Lactobacillus hilgardii, Lactobacillus buchneri, and Lactobacillus brevis. We establish the specificity of 16S rDNA sequencing in the differentiation of these species and in the rejection of the Lactobacillus vermiforme species name. Moreover, we succeeded in differentiating these heterofermentative species by means of recA gene sequence comparison. Short homologous regions were amplified by PCR with degenerate consensus primers, sequenced, and 280 bp were analysed and considered for the inference of phylogenetic trees. The phylogram obtained was coherent and clearly separated the three species. The recA gene sequence was a reliable and useful method that allowed a good discrimination among closely related species. The validity of the recA gene sequence, restriction fragment length polymorphism (RFLP) analysis of the PCR-amplified 16S-23S rDNA intergenic spacer region (ISR), and random amplified polymorphic DNA (RAPD) to study the L. hilgardii intraspecies heterogeneity was tested in five strains isolated from stuck wine fermentations at the same winery in the same vintage. The results indicated that L. hilgardii is a heterogeneous species. Since L. hilgardii is a malolactic species that can influence the final quality of the wine, the presence of oenological relevant genes, such as those involved in ethyl carbamate or biogenic amine production, was investigated.

Isolation and identification of novel high strength phenol degrading bacterial strains from phenol-formaldehyde resin manufacturing industrial wastewater

Phenols are toxic to all types of organisms. Two bacterial strains capable of utilizing phenol as a sole carbon source were isolated from the phenol bearing industrial wastewater. Based on the biochemical test results the organisms were identified as Pseudomonas cepacia and Bacillus brevis. The organisms were very efficient in phenol degradation, the lag phase increased with increase in phenol concentration. The well-acclimatized cultures of P. cepacia and B. brevis degraded 2500 and 1750 mg l(-1) of phenol in 144 h, respectively. The organisms degrade phenol even in the presence of toxicants like thiocyanate, sulphide and cyanide. The organisms can be effectively used for treating high strength phenol containing thiocyanate, sulphide and cyanide. The P. cepacia degrades phenol with a faster rate than B. brevis. P. cepacia can be used effectively for treating high strength phenolic wastewater.

[Viability of a native isolate of Lactobacillus brevis in a fermented milky drink]

The objective of this research was to test the viability of a native isolate of Lactobacillus brevis in two fermented milky drinks: a drink without prebiotic ingredient and another drink with oat flour (0.5%, p/v) as prebiotic ingredient. The viability of L. brevis was tested at 7, 14, and 21 after inoculation. Drink pH and lactic acid concentration was measured as a function of time (2, 7, 14, and 21 days after inoculation). The isolate was viable in both drinks because its counting plates was higher than 10(6) CFU/mL until day 21st. Between the 7th and 14th day, the rate of growth was higher in the drink that included oat flour, however, at the day 21st the colony density was similar in both drinks.

Characterization of Lactobacillus strains and monitoring by RAPD-PCR in controlled fermentations of “Almagro” eggplants

The characterization of 23 Lactobacillus strains was performed. The strains were assayed for biogenic amine-forming capacity, hydrogen peroxide production, pectin esterase, cellulase and polygalacturonase production, growth rate, acidifying capacity and salt tolerance. Three strains were selected which belonged to the species, Lactobacillus brevis, Lactobacillus plantarum and Lactobacillus fermentum. Different starter cultures prepared as combinations of these three strains were assayed in pilot scale fermentations and Randomly Amplified Polymorphic DNA (RAPD) analysis, using a previously selected random primer, was applied for monitoring the inoculated strains. The course of fermentations was similar in all batches but sensorial analysis of eggplants fermented using a mixed culture of the three strains displayed the best results, and no differences were obtained when compared with commercial eggplants.