Probiotic characteristics of Lactobacillus plantarum E680 and its effect on Hypercholesterolemic mice

Proteomic Analysis of Milk Fat Globule Membrane Protein Modulation of Differently Expressed Proteins in Lactobacillus plantarum under Bile Salt Stress

Tolerance to bile stress is a crucial property for lactic acid bacteria (LAB) to survive in the gastrointestinal tract and exert their beneficial effects. Whey powder enriched with milk fat globule membrane proteins (M-WPI) as a functional component is protective for strains under stress conditions. The current study investigated the key mechanisms of action involved in Lactobacillus plantarum (L. plantarum) CGMCC 23701 survival in the presence of bile and the protective mechanism of M-WPI. According to proteomic analysis (proteomics), there could be several reasons for the greater protective effect of M-WPI. These include promoting the synthesis of fatty acids and peptidoglycans to repair the structure of the cell surface, regulating the metabolism of carbohydrates and amino acids to release energy and produce a range of precursors, enabling the expression of the repair system to repair damaged DNA, and promoting the expression of proteins associated with the multidrug efflux pump, which facilitates the exocytosis of intracellular bile salts. This study helps us to better understand the changes in proteome of L. plantarum CGMCC 23701 under bile salt stress and M-WPI protection, which will provide a new method for the protection and development of functional LAB.

Genomics-based analysis of four porcine-derived lactic acid bacteria strains and their evaluation as potential probiotics

The search for probiotics and exploration of their functions are crucial for livestock farming. Recently, porcine-derived lactic acid bacteria (LAB) have shown great potential as probiotics. However, research on the evaluation of porcine-derived LAB as potential probiotics through genomics-based analysis is relatively limited. The present study analyzed four porcine-derived LAB strains (Lactobacillus johnsonii L16, Latilactobacillus curvatus ZHA1, Ligilactobacillus salivarius ZSA5 and Ligilactobacillus animalis ZSB1) using genomic techniques and combined with in vitro tests to evaluate their potential as probiotics. The genome sizes of the four strains ranged from 1,897,301 bp to 2,318,470 bp with the GC contents from 33.03 to 41.97%. Pan-genomic analysis and collinearity analysis indicated differences among the genomes of four strains. Carbohydrate active enzymes analysis revealed that L. johnsonii L16 encoded more carbohydrate active enzymes than other strains. KEGG pathway analysis and in vitro tests confirmed that L. johnsonii L16 could utilize a wide range of carbohydrates and had good utilization capacity for each carbohydrate. The four strains had genes related to acid tolerance and were tolerant to low pH, with L. johnsonii L16 showing the greatest tolerance. The four strains contained genes related to bile salt tolerance and were able to tolerate 0.1% bile salt. Four strains had antioxidant related genes and exhibited antioxidant activity in in vitro tests. They contained the genes linked with organic acid biosynthesis and exhibited antibacterial activity against enterotoxigenic Escherichia coli K88 (ETEC K88) and Salmonella 6,7:c:1,5, wherein, L. johnsonii L16 and L. salivarius ZSA5 had gene clusters encoding bacteriocin. Results suggest that genome analysis combined with in vitro tests is an effective approach for evaluating different strains as probiotics. The findings of this study indicate that L. johnsonii L16 has the potential as a probiotic strain among the four strains and provide theoretical basis for the development of probiotics in swine production.

In vitro assessment of biofunctional properties of Lactiplantibacillus plantarum strain Jb21-11 and the characterization of its exopolysaccharide

ABSTACT

The microbiota of traditional food provides a rich reservoir of biodiversity to find new strains with interesting features for novel functional food formulation. Therefore, this study aimed to investigate the biofunctional potential of the lactic acid bacteria (LAB) strain Jb21-11 isolated from Jben, a traditional Algerian fresh cheese. This isolate was selected out of a collection of 154 LAB based on its exopolysaccharide (EPS) phenotype and was preliminarily identified by polyphasic characterization as Lactiplantibacillus plantarum (previously known as Lactobacillus plantarum) and its biofunctional properties were then assessed in vitro. The tested strain demonstrated good resistance to gastric juice, acidity around pH 2, and 2% (v/v) bile salts, which are important characteristics for potential biofunctional LAB candidates. It also showed a good production of ropy EPS with 674 mg/L on MRS medium. However, this ability appears to compromise the adhesion of the strain to Caco-2 cells (less than 1%), which according to our results, seems not to be related to autoaggregation and hydrophobicity (44.88 ± 0.028% and 16.59 ± 0.012%). Furthermore, promising antimicrobial activity against three pathogenic bacteria (Escherichia coli, Staphylococcus aureus, and Salmonella) was detected probably due to antimicrobial metabolites excreted during fermentation process into the medium. Moreover, the strain L. plantarum Jb21-11 displayed a therapeutic functionality with both anti-inflammatory and immunomodulatory action using RAW 264.7 cells. The chemical features of the novel ropy Jb21-11-EPS were also investigated revealing the presence of three monosaccharides, namely, mannose, galactose, and glucose, with a molar ratio of 5.42:1.00:4.52 linked together by α- and β-glycosidic bonds, presenting a relatively high molecular weight of 1.08 × 105 Da of interest for a texturing potential. Therefore, the new producing EPS strain Jb21-11 is a promising candidate for use as an adjunct culture for improving the texture of functional food.

Modulation of the Gut Microbiota by Nutrition and Its Relationship to Epigenetics

The intestinal microbiota is a community of microorganisms inhabiting the human intestines, potentially influencing both physiological and pathophysiological processes in the human body. Existing evidence suggests that nutrients can influence the modulation of the gut microbiota. However, there is still limited evidence regarding the effects of vitamin and mineral supplementation on the human gut microbiota through epigenetic modification. It is plausible that maintaining an adequate dietary intake of vitamin D, iron, fibre, zinc and magnesium may have a beneficial effect on alleviating inflammation in the body, reducing oxidative stress, and improving the condition of the intestinal microbiota through various epigenetic mechanisms. Moreover, epigenetics involves alterations in the phenotype of a cell without changing its fundamental DNA sequence. It appears that the modulation of the microbiota by various nutrients may lead to epigenetic regulation. The correlations between microbiota and epigenetics are potentially interdependent. Therefore, the primary objective of this review is to identify the complex relationships between diet, gut microbiota, and epigenetic regulation. These interactions could play a crucial role in systemic health.

Optimization of Gamma-Aminobutyric Acid Production by Lactiplantibacillus plantarum FRT7 from Chinese Paocai

Gamma-aminobutyric acid (GABA) is a widely available non-protein amino acid whose physiological importance goes beyond its role as an inhibitory neurotransmitter in mammals. The GABA synthesis ability of ten strains of Lactiplantibacillus plantarum was screened. They produced GABA ranging from 48.19 ± 3.44 to 100.75 ± 1.63 mg/L at 24 h-cultivation. Among them, Lp. plantarum FRT7 showed the highest GABA production. Therefore, FRT7 was chosen for GABA yield optimization. A one-factor-at-a-time strategy analysis of the GABA yield of FRT7 was performed, including the culture temperature, incubation time, inoculum volume, initial pH, the initial amount of monosodium glutamate (MSG), and pyridoxal 5'-phosphate (PLP) concentration, based on which the response surface methodology (RSM) was performed. After being cultured in an MRS culture medium supplemented with 3% MSG and 2 mmol/L of PLP at 40 °C with an initial pH of 7.0 for 48 h, the GABA reached a maximum yield of 1158.6 ± 21.22 mg/L. The results showed the experimental value of the GABA yield was in good agreement with the predicted values. Furthermore, the results from the RSM also indicated that the initial MSG addition, PLP concentration, and incubation time were significant variables. These results suggest that Lp. plantarum FRT7 has the potential to be a health-beneficial probiotic with commercial capabilities.

Impact of Lactiplantibacillus plantarum Inducia on metabolic and antioxidative response in cholesterol and BMI variable indices: randomised, double-blind, placebo-controlled trials

Probiotics may have potential in reducing cardiovascular disease (CVD) risk in middle-aged persons with borderline metabolic indices. The ability of potential probiotic Lactiplantibacillus plantarum Inducia to reduce CVD risk factors in persons with variable cholesterol and body mass indices (BMI) was assessed. In two parallel-armed double-blind placebo-controlled interventions (n=136) and (n=104), participants daily received either test yoghurt (Inducia) or placebo yoghurt. BMI, blood pressure, plasma glucose, cholesterol, high-sensitivity C-reactive protein (hs-CRP), oxidative stress and immunological markers were measured. Total counts of lactobacilli and L. plantarum Inducia were evaluated using real-time PCR. Significant reduction of total cholesterol, low density lipoprotein cholesterol (LDL-c) and non-high-density cholesterol occurred in both trials. The change in cholesterol (P=0.023) in persons with normal BMI and borderline cholesterol levels after four weeks of yoghurt consumption was detected. A difference was also found between placebo and test yoghurt groups (P=0.042) in LDL-c with normal BMI. Blood glucose reduction (P=0.01) and antioxidative effect was detected in overweight volunteers of the test yoghurt group. The suppression of oxidised LDL was associated with lowered oxidative stress index and total peroxide concentration values and faecal recovery of Inducia. The Inducia strain expresses antioxidative effect on blood lipids and has anti-glycaemic impact that allow to apply it as dietary probiotic supplement for the management of CVD risks in humans.

Lactobacillus plantarum ZJUIDS14 alleviates non-alcoholic fatty liver disease in mice in association with modulation in the gut microbiota

This present study was designed to explore the protective role of Lactobacillus plantarum ZJUIDS14 against Non-alcoholic Fatty Liver Disease (NAFLD) in a high-fat-diet (HFD)-induced C57BL/6 mice model. The probiotic (10⁹ CFU/every other day) was administered by oral gavage for 12 weeks. We found that L. plantarum ZJUIDS14 intervention significantly alleviated HFD related hepatic steatosis, liver damage, insulin resistance, and increased hepatic expression of peroxisome proliferator activated receptor α (PPAR-α) while stimulating the activation of AMP-activated protein kinase (AMPK). Furthermore, L. plantarum ZJUIDS14 improved mitochondrial function as reflected by an increase in dynamin related protein 1 (DRP1) and a decrease of proteins associated with oxidative phosphorylation (OXPHOS) after the treatment. Additionally, mice from the L. plantarum ZJUIDS14 group had a restored intestinal flora and homeostasis involving Coprostanoligenes group, Ruminococcaceae UCG-014, Allobaculum, Ruminiclostridium 1, and Roseburia. Meanwhile, these five genera exhibited a significant (negative or positive) association with ileum inflammation mRNA levels and SCFA contents, by Spearman's correlation analysis. In general, our data demonstrated that L. plantarum ZJUIDS14 mitigates hepatic steatosis and liver damage induced by HFD. Specifically, they strengthened the integrity of the intestinal barrier, regulated gut microbiota, and improved mitochondrial function. Our data provide an experimental basis for L. plantarum ZJUIDS14 as a promising candidate to prevent NAFLD.

In-process real-time probiotic phenotypic strain identity tracking: The use of Fourier transform infrared spectroscopy

Probiotic bacteria, capable of conferring benefits to the host, can present challenges in design, development, scale-up, manufacturing, commercialization, and life cycle management. Strain identification is one of the main quality parameters; nevertheless, this task can be challenging since established methodologies can lack resolution at the strain level for some microorganisms and\or are labor-intensive and time-consuming. Fourier transform infrared spectroscopy (FTIRS) has been largely used for the investigation of pathogenic species in the clinical field, whereas only recently has been proposed for the identification of probiotic strains. Within the probiotic industrial production, bacterial strains can be subjected to stressful conditions that may affect genomic and phenotypic characteristics; therefore, real-time monitoring of all the sequential growth steps is requested. Considering the fast, low-cost, and high-throughput features, FTIRS is an innovative and functional technology for typing probiotic strains from bench-top experiments to large-scale industrial production, allowing the monitoring of stability and identity of probiotic strains. In this study, the discriminatory power of FTIRS was assessed for four Lactiplantibacillus plantarum probiotic strains grown under different conditions, including temperatures (30 and 37°C) and medium (broth and agar), after consecutive sub-culturing steps. A comparison between the generated spectra with pulsed-field gel electrophoresis (PFGE) profiles was also performed. FTIRS was not only able to distinguish the strains of L. plantarum under different growth conditions but also to prove the phenotypic stability of L. plantarum type strain LP-CT after six growing steps. Regardless of the growth conditions, FTIRS spectra related to LP-CT constituted a unique hierarchical cluster, separated from the other L. plantarum strains. These results were confirmed by a PFGE analysis. In addition, based on FTIRS data, broth cultures demonstrated a higher reproducibility and discriminatory power with respect to agar ones. These results support the introduction of FTIRS in the probiotic industry, allowing for the step-by-step monitoring of massive microbial production while also guaranteeing the stability and purity of the probiotic strain. The proposed novel approach can constitute an impressive improvement in the probiotic manufacturing process.

Lactic acid bacteria isolated from Chinese traditional fermented milk as novel probiotic strains and their potential therapeutic applications

Lactic acid bacteria (LAB) are believed to have health-promoting properties to the host and can be used in therapeutics interventions; intriguingly, they have the property to produce bio-preservatives substances. Therefore, this study aimed to mine probiotics and evaluate their safety, functional properties, and cholesterol-lowering capability. Seven potential probiotic strains were compared from 56 LAB strains isolated from traditional Chinese fermented milk. The results showed that all tested strains are tolerant to gastric acidity (45.5-83.26) and bile salts (11.92-92.91%) and have antibacterial activity against Staphylococcus aureus ATCC25923 and Escherichia coli ATCC25922. Likewise, it lowered the cholesterol levels in vitro by live cells (26.57-45.76%) and dead cells (29.53-50.97%) with remarkable aggregation ability (13.8-43.71%). Antioxidant properties and produce short chain fatty acids (SCFAs) were strain-dependent features. Upon assessment of the safety, Enterococcus faecium NWAFU-BIO-AS14 exhibited virulence factors genes (VFs) of (mur-2ed, odc, and tet(K)) and + hemolysis activity. While Enterococcus faecium NWAFU-BIO-A-B24 and Limosilactobacillus fermentum NWAFU-BIO-B-S6 have VFs of (odc, vanC2, and ant(6)-Ia). Limosilactobacillus fermentum NWAFU-BIO-D-B2 has only (odc). Thus, they are not considered as safe probiotics. In contrast, Lactiplantibacillus plantarum NWAFU-BIO-BS29, Companilactobacillus crustorum NWAFU-BIO-AS16, and Lactobacillus gallinarum NWAFU-BIO-D-S7 are the safest and best strains, respectively, due to the absence of 16 VFs and their sensitivity to antibiotics such as kanamycin, erythromycin, tetracycline, gentamycin, vancomycin, streptomycin, chloramphenicol, and ampicillin. Accordingly, these strains have a high potentiality to be used as starter cultures or safely applied as perfect probiotics in functionals food and feed.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03403-z.

Probiotic of Lactiplantibacillus plantarum NWAFU-BIO-BS29 Isolated from Chinese Traditional Fermented Milk and Its Potential Therapeutic Applications Based on Gut Microbiota Regulation

Lactic acid bacteria are one of the bioresources that can promote the host's health and have potential therapeutic applications. This study aimed to evaluate the probiotic properties of novel Lactiplantibacillus plantarum NWAFU-BISO-BS29 isolated in vitro from traditional Chinese fermented milk, assess its safety, and study its interaction with the gut microbiota using a BALB/c mouse model. The findings reveal that this strain had a high tolerance to gastric acidity (64.4%) and bile salts (19.83-87.92%) with remarkable auto-aggregation and co-aggregation abilities (33.01-83.96%), respectively. Furthermore, it lowered the cholesterol levels in dead cells (44.02%) and live cells (34.95%) and produced short-chain fatty acids (SCFAs). Likewise, it showed good antioxidant properties and strong antipathogen activity against Escherichia coli and Staphylococcus aureus with inhibition zones at 21 and 25 mm, respectively. The safety assessment results indicate that all of the virulence factor genes were not detected in the whole DNA; additionally, no hemolysis or resistance to antibiotics commonly used in food and feed was observed. Interestingly, the 16S rRNA gene sequencing of the mouse gut microbiota showed a marked alteration in the microbial composition of the administrated group, with a noticeable increase in Firmicutes, Patescibacteria, Campylobacterota, Deferribacterota, Proteobacteria, and Cyanobacteria at the phylum level. The modulation of gut microbial diversity significantly improved the production of SCFCs due to the abundance of lactobacillus genera, which was consistent with the functional gene predictive analysis and is believed to have health-promoting properties. Based on these results, our novel strain is considered a safe and good probiotic and could hold high potential to be used as a starter culture or to safely supplement functional foods as a probiotic and may provide new insights into therapeutic interventions.

Lactobacillus gasseri RW2014 Ameliorates Hyperlipidemia by Modulating Bile Acid Metabolism and Gut Microbiota Composition in Rats

Hyperlipidemia is a leading risk of cardiovascular and cerebrovascular disease. Dietary supplementation with probiotics has been suggested as an alternative intervention to lower cholesterol. In the current study, we isolated a strain of Lactobacillus gasseri RW2014 (LGA) from the feces of a healthy infant fed with breast milk, and it displayed bile salt hydrolase (BSH) activity. Using this strain we determined its cholesterol-lowering and fatty liver-improving functions. SD rats were randomly divided into four groups. The control rats were fed a commercial chow diet and the other three groups were fed a high-fat diet (HFD) for a 7-week experiment period. After two weeks of feeding, the rats in PBS, simvastin, and LGA group were daily administered through oral gavage with 2 mL PBS, simvastin (1 mg/mL), and 2 × 10⁹ CFU/mouse live LGA in PBS, respectively. After five weeks of such treatment, the rats were euthanized and tissue samples were collected. Blood lipid and inflammatory factors were measured by ELISA, gut microbiota was determined by 16S rRNA sequencing, and bile acids profiles were detected by metabolomics. We found that LGA group had lower levels of blood cholesterol and liver steatosis compared to the simvastin group. LGA also significantly reducedthe levels of inflammatory factors in the serum, including TNFα, IL-1β, MCP-1, IL-6, and exotoxin (ET), and increased the levels of short-chain fatty acids in feces, including isobutyric acid, butyric acid, isovaleric acid, valeric acid, and hexanoic acid. In addition, LGA altered the compositions of gut microbiota as manifested by the increased ratio of Firmicutes/Bacteroides and the relative abundance of Blautia genus. Targeted metabolomics results showed that bile acids, especially free bile acids and secondary bile acids in feces, were increased in LGA rats compared with the control rats. Accordingly, the rats administrated with LGA also had a higher abundance of serum bile acids, including 23-norcholic acid, 7-ketolithocholic acid, β-muricholic acid, cholic acid, and deoxycholic acid. Together, this study suggests that LGA may exert a cholesterol-lowering effect by modulating the metabolism of bile acids and the composition of gut microbiota.

Antimicrobial activity against Staphylococcus aureus and genome features of Lactiplantibacillus plantarum LR-14 from Sichuan pickles

The persistence of Staphylococcus aureus within biofilm can lead to contamination of medical devices and life-threatening infections. Luckily, lactic acid bacteria (LAB) have an inhibitory effect on the growth of these bacteria. This study aims to select LAB strains from fermented vegetables, and analyze their potential inhibition activities against S. aureus. In total, 45 isolates of LAB were successfully isolated from Sichuan pickles, and the CFS of Lactiplantibacillus plantarum LR-14 exerted the strongest inhibitory effect against S. aureus. Moreover, S. aureus cells in planktonic and biofilm states both wrinkled and damaged when treated with the CFS of L. plantarum LR-14. In addition, whole genome sequencing analysis indicates that L. plantarum LR-14 contains various functional genes, including predicted extracellular polysaccharides (EPS) biosynthesis genes, and genes participating in the synthesis and metabolism of fatty acid, implying that L. plantarum LR-14 has the potential to be used as a probiotic with multiple functions.

Active Peptide AR-9 From Eupolyphaga sinensis Reduces Blood Lipid and Hepatic Lipid Accumulation by Restoring Gut Flora and Its Metabolites in a High Fat Diet–Induced Hyperlipidemia Rat

The dysbiosis of gut flora and its metabolites plays important roles in the progression of hyperlipidemia (HL), and some bioactive peptides are available for HL treatment. In this study, we aimed to isolate an active peptide (AR-9) from active peptides of E. sinensis (APE) and determine whether AR-9 could improve many symptoms of a HL rat induced by a high-fat diet (HFD) by modulating gut flora and its metabolites. Above all, AR-9 was derived from APE using ion-exchange chromatography, and its structure was deconstructed by Fourier transform infrared spectrometer (FT-IR), circular dichroism (CD) spectroscopy, and UHPLC-Q-Exactive-Orbitrap MS. Then, an HFD-induced HL model in SD rats was established and used to clarify the regulatory effects of AR-9 (dose of 3 mg/kg) on HL. Normal diet–fed rats were taken as the control. The plasma samples and liver were harvested for biochemical and histopathological examinations. 16S rRNA gene sequencing and untargeted metabolomics were sequenced to assess changes in gut flora and its metabolites from rat fecal samples. Finally, Spearman’s correlation analysis was used to assess the relationship between lipid-related factors, gut flora, and its metabolites so as to evaluate the mechanism of AR-9 against HL. The results of the separation experiments showed that the amino acid sequence of AR-9 was AVFPSIVGR, which was a fragment of the actin protein from Blattaria insects. Moreover, HFD rats developed exaltation of index factors, liver lipid accumulation, and simple fibrosis for 8 weeks, and the profiles of gut flora and its metabolites were significantly altered. After treatment, AR-9 decreased the levels of lipid factors in plasma and the extent of liver damage. 16S rRNA gene sequencing results indicated that AR-9 significantly increased the relative abundance of beneficial bacteria Bacteroidetes and reduced the relative abundance of the obesity-associated bacteria Firmicutes. Furthermore, AR-9 changed gut microbiota composition and increased the relative abundance of beneficial bacteria: Lactobacillus, Clostridium, Dehalobacterium, and Candidatus arthromitus. Fecal metabolomics showed that the pathway regulated by AR-9 was “arginine biosynthesis”, in which the contents were citrulline and ornithine. Spearman’s correlation analysis revealed that two metabolites (ornithine and citrulline) showed significantly negative correlations with obesity-related parameters and positive correlations with the gut genera (Clostridium) enriched by AR-9. Overall, our results suggested interactions between gut microbial shifts and fecal amino acid/lipid metabolism and revealed the mechanisms underlying the anti-HL effect of AR-9. The abovementioned results not only reveal the initial anti-HL mechanism of AR-9 but also provide a theoretical basis for the continued development of AR-9.

Lactobacillus plantarum FRT4 alleviated obesity by modulating gut microbiota and liver metabolome in high-fat diet-induced obese mice

Background

Obesity has become a global epidemic recognized by the World Health Organization. Probiotics supplementation has been shown to contribute to improve lipid metabolism. However, mechanisms of action of probiotics against obesity are still not clear. Lactobacillus plantarum FRT4, a probiotic previously isolated from a kind of local yogurt, had good acid and bile salt tolerance and lowered cholesterol in vitro.

Objective

This study aimed to evaluate the effect of L. plantarum FRT4 on serum and liver lipid profile, liver metabolomics, and gut microbiota in mice fed with a high-fat diet (HFD).

Design

Mice were fed with either normal diet or HFD for 16 weeks and administered 0.2 mL of 1 × 10⁹ or 1 × 10¹⁰ CFU/mL dosage of L. plantarum FRT4 during the last 8 weeks of the diet. Cecal contents were analyzed by 16S rRNA sequencing. Hepatic gene expression and metabolites were detected by real-time quantitative polymerase chain reaction (PCR) and metabolomics, respectively.

Results

L. plantarum FRT4 intervention significantly reduced the HFD-induced body weight gain, liver weight, fat weight, serum cholesterol, triglyceride, and alanine aminotransferase (ALT) levels in the liver (P < 0.05). Liver metabolomics demonstrated that the HFD increased choline, glycerophosphocholine, and phosphorylcholine involved in the glycerophospholipid metabolism pathway. All these changes were reversed by FRT4 treatment, bringing the levels close to those in the control group. Further mechanisms showed that FRT4 favorably regulated gut barrier function and pro-inflammatory biomediators. Furthermore, FRT4 intervention altered the gut microbiota profiles and increased microbial diversity. The relative abundances of Bacteroides, Parabateroides, Anaerotruncus, Alistipes, Intestinimonas, Butyicicoccus, and Butyricimonas were significantly upregulated. Finally, Spearman's correlation analysis revealed that several specific genera were strongly correlated with glycerophospholipid metabolites (P < 0.05).

Conclusions

These findings suggested that L. plantarum FRT4 had beneficial effects against obesity in HFD-induced obese mice and can be used as a potential functional food for the prevention of obesity.

Probiotic Potential of Lactobacillus Strains Isolated From Fermented Vegetables in Shaanxi, China

The objective of this study was to assess in vitro probiotic potential of Lactobacillus strains derived from artisanal fermented vegetables in Shaanxi, China. In total, 74 acid-producing Gram-positive strains with rod-shaped under the microscope were isolated from 16 samples of spontaneously fermented vegetables. Out of 74 strains, 26 showed high survival rate under low pH and high bile salts conditions and were subjected to molecular identification by 16S rRNA gene sequencing analysis. The results showed that 15 isolates belonged to Lactobacillus plantarum, 9 isolates belonged to Lactobacillus brevis, and the 2 remaining strains belonged to Weissella viridescens. The 24 Lactobacillus strains were investigated for their survival rate to transit simulated gastrointestinal tract, cell surface hydrophobicity, auto-aggregation, co-aggregation with pathogen, adhesion to Caco-2, antimicrobial activity, antibiotics susceptibility, radical scavenging ability, α-glucosidase inhibition, and the cholesterol assimilation. The results showed that the probiotic characteristics were strain-dependent, and several strains exhibited great probiotic potential with specific health benefits, which indicated that they might be excellent candidates for production of functional foods. Interestingly, it was first found that L. plantarum generally had higher antibacterial activities, α-glucosidase inhibition ability, and antibiotics susceptibility compared to L. brevis in this study. The results indicated that Lactobacillus strains isolated from fermented vegetables in Shaanxi, China, could be exploited as a promising novel probiotic source.

Chewing the Fat with Microbes: Lipid Crosstalk in the Gut

It is becoming increasingly important for any project aimed at understanding the effects of diet on human health, to also consider the combined effect of the trillions of microbes within the gut which modify and are modified by dietary nutrients. A healthy microbiome is diverse and contributes to host health, partly via the production and subsequent host absorption of secondary metabolites. Many of the beneficial bacteria in the gut rely on specific nutrients, such as dietary fiber, to survive and thrive. In the absence of those nutrients, the relative proportion of good commensal bacteria dwindles while communities of opportunistic, and potentially pathogenic, bacteria expand. Therefore, it is unsurprising that both diet and the gut microbiome have been associated with numerous human diseases. Inflammatory bowel diseases and colorectal cancer are associated with the presence of certain pathogenic bacteria and risk increases with consumption of a Western diet, which is typically high in fat, protein, and refined carbohydrates, but low in plant-based fibers. Indeed, despite increased screening and better care, colorectal cancer is still the 2nd leading cause of cancer death in the US and is the 3rd most diagnosed cancer among US men and women. Rates are rising worldwide as diets are becoming more westernized, alongside rising rates of metabolic diseases like obesity and diabetes. Understanding how a modern diet influences the microbiota and how subsequent microbial alterations effect human health will become essential in guiding personalized nutrition and healthcare in the future. Herein, we will summarize some of the latest advances in understanding of the three-way interaction between the human host, the gut microbiome, and the specific class of dietary nutrients, lipids.

The Effect of Lactobacillus plantarum Extracellular Vesicles from Korean Women in Their 20s on Skin Aging

Extracellular vesicles, which are highly conserved in most cells, contain biologically active substances. The vesicles and substances interact with cells and impact physiological mechanisms. The skin is the most external organ and is in direct contact with the external environment. Photoaging and skin damage are caused by extrinsic factors. The formation of wrinkles is a major indicator of skin aging and is caused by a decrease in collagen and hyaluronic acid. MMP-1 expression is also increased. Due to accruing damage, skin aging reduces the ability of the skin barrier, thereby lowering the skin’s ability to contain water and increasing the amount of water loss. L. plantarum suppresses various harmful bacteria by secreting an antimicrobial substance. L. plantarum is also found in the skin, and research on the interactions between the bacteria and the skin is in progress. Although several studies have investigated L. plantarum, there are only a limited number of studies on extracellular vesicles (EV) derived from L. plantarum, especially in relation to skin aging. Herein, we isolated EVs that were secreted from L. plantarum of women in their 20s (LpEVs). We then investigated the effect of LpEVs on skin aging in CCD986sk. We showed that LpEVs modulated the mRNA expression of ECM related genes in vitro. Furthermore, LpEVs suppressed wrinkle formation and pigmentation in clinical trials. These results demonstrated that LpEVs have a great effect on skin aging by regulating ECM related genes. In addition, our study offers important evidence on the depigmentation effect of LpEVs.

Lactobacillus johnsonii BFE6154 Ameliorates Diet-Induced Hypercholesterolemia

The functional characteristics of Lactobacillus johnsonii BFE6154, first isolated from Maasai traditional fermented milk, were previously identified in vitro, but its cholesterol-lowering properties have not been verified yet. In this study, we investigated the effect of L. johnsonii BFE6154 on cholesterol regulation and the mode of action. Stimulation of Caco-2 intestinal epithelial cells with L. johnsonii BFE6154 downregulated the gene expression of Niemann-Pick C1-like 1 (NPC1L1) through the activation of liver X receptor (LXR). Also, stimulation of HepG2 cells with the metabolites produced by L. johnsonii BFE6154 revealed an increase in the gene expression of low-density lipoprotein receptor (LDLR). Oral administration of L. johnsonii BFE6154 in mice receiving a high-fat and high-cholesterol diet (HFHCD), reduced total cholesterol and low-density lipoprotein-cholesterol (LDL) and increased high-density lipoprotein-cholesterol (HDL) in the blood, compared to the control. Diet-induced hypercholesterolemic mice receiving L. johnsonii BFE6154 showed a suppression of cholesterol absorption under the control of NPC1L1 in the intestine. Furthermore, L. johnsonii BFE6154 consumption ameliorated the hepatic cholesterol level and LDLR expression, which was reduced by HFHCD. These molecular modulations led to the increase of cholesterol excretion and the decrease of cholesterol levels in the feces and liver, respectively. Taken together, these results suggest that L. johnsonii BFE6154 may protect against diet-induced hypercholesterolemia through the regulation of cholesterol metabolism in the intestine and liver.

Therapeutic and Improving Function of Lactobacilli in the Prevention and Treatment of Cardiovascular-Related Diseases: A Novel Perspective From Gut Microbiota

The occurrence and development of cardiovascular-related diseases are associated with structural and functional changes in gut microbiota (GM). The accumulation of beneficial gut commensals contributes to the improvement of cardiovascular-related diseases. The cardiovascular-related diseases that can be relieved by Lactobacillus supplementation, including hypercholesterolemia, atherosclerosis, myocardial infarction, heart failure, type 2 diabetes mellitus, and obesity, have expanded. As probiotics, lactobacilli occupy a substantial part of the GM and play important functional roles through various GM-derived metabolites. Lactobacilli ultimately have a beneficial impact on lipid metabolism, inflammatory factors, and oxidative stress to relieve the symptoms of cardiovascular-related diseases. However, the axis and cellular process of gut commensal Lactobacillus in improving cardiovascular-related diseases have not been fully elucidated. Additionally, Lactobacillus strains produce diverse antimicrobial peptides, which help maintain intestinal homeostasis and ameliorate cardiovascular-related diseases. These strains are a field that needs to be further investigated immediately. Thus, this review demonstrated the mechanisms and summarized the evidence of the benefit of Lactobacillus strain supplementation from animal studies and human clinical trials. We also highlighted a broad range of lactobacilli candidates with therapeutic capability by mining their metabolites. Our study provides instruction in the development of lactobacilli as a functional food to improve cardiovascular-related diseases.

Complete genome sequencing of Peyer's patches-derived Lactobacillus taiwanensis CLG01, a potential probiotic with antibacterial and immunomodulatory activity

Background

The genus Lactobacillus is an important component of the gastrointestinal tract of human and animals and commonly considered as probiotic. L. taiwanensis has long been proposed to be a probiotic whereas understanding on this species is still in its infancy. Genomic information of L. taiwanensis is fairly limited. Extensive characterization of its beneficial traits is needed.

Results

A new strain CLG01 of L. taiwanensis was isolated from mouse Peyer’s patches. We established its probiotic profile through in vitro experiments. Complete genome of this strain was also sequenced and analyzed. L. taiwanensis CLG01 showed robust tolerance to acid and a degree of tolerance to bile salt with a promising antibacterial activity against a broad spectrum of pathogenic bacteria. In vitro treatment of mouse RAW 264.7 macrophage cells with heat-killed bacteria and bacterial supernatant of L. taiwanensis CLG01 resulted in enhancement of immune responses and upregulated expression of TNF-α and IL-6. The strain CLG01 also increased the IL-10 production of macrophages when co-treated with lipopolysaccharide (LPS). Complete genome of L. taiwanensis CLG01 contained a 1.89 Mb chromosome and two plasmids. Further genomic analysis revealed the presence of genes related to its resistance to different stresses and the beneficial effects mentioned above. Moreover, biosynthetic gene clusters (BGCs) encoding antimicrobial peptides, like bacteriocin, linear azol(in)e-containing peptide (LAP) and lanthipeptide, were also identified in the genome of L. taiwanensis CLG01.

Conclusions

L. taiwanensis CLG01, isolated from mouse Peyer’s patches, is the first L. taiwanensis strain with both phenotypes and genotypes systematically studied. These preliminary data confirmed the role of L. taiwanensis CLG01 as a potential probiotic candidate with antibacterial and immunomodulatory activity, which provide insight for further investigation to this species.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02127-z.