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Lactobacillus plantarum AR495 is a widely used probiotic for the treatment of various digestive diseases, including irritable bowel syndrome (IBS). However, the specific mechanisms of L. plantarum AR495 in alleviating IBS remain unclear. Abnormal intestinal tryptophan metabolism can cause disordered immune responses, gastrointestinal peristalsis, digestion and sensation, which is closely related to IBS pathogenesis. The aim of this study is to explore the effects and mechanisms of L. plantarum AR495 in regulating tryptophan metabolism. Primarily, tryptophan and its related metabolites in patients with IBS and healthy people were analyzed, and an IBS rat model of acetic acid enema plus restraint stress was established to explore the alleviation pathway of L. plantarum AR495 in tryptophan metabolism. It was found that the 5-HT pathway was significantly changed, and the 5-HTP and 5-HT metabolites were significantly increased in the feces of patients with IBS, which were consistent with the results obtained for the IBS rat model. Maladjusted 5-HT could increase intestinal peristalsis and lead to an increase in the fecal water content and shapeless stool in rats. On the contrary, these two metabolites could be restored to normal levels via intragastric administration of L. plantarum AR495. Further study of the metabolic pathway showed that L. plantarum AR495 could effectively reduce the abundance of 5-HT by inhibiting the expression of enterochromaffin cells rather than promoting its decomposition. In addition, the results showed that L. plantarum AR495 did not affect the expression of SERT. To sum up, L. plantarum AR495 could restore the normal levels of 5-HT by inhibiting the abnormal proliferation of enterochromaffin cells and the excessive activation of TPH1 to inhibit the intestinal peristalsis in IBS. These findings provide insights for the use of probiotics in the treatment of IBS and other diarrheal diseases.

Western diet is thought to increase susceptibility to inflammatory bowel disease (IBD), and probiotics are a potential therapeutic agent for IBD. This study revealed the effects of Lactobacillus plantarum AR113 and L. plantarum AR113Δ bsh 1 on a dextran sulfate sodium (DSS)-induced colitis mouse model under the Western diet (WD). After four weeks of WD and low-sugar and low-fat diet (LD) intervention, induction with 3% DSS, and intragastric administration of probiotics, we found that L. plantarum AR113 could regulate blood glucose and lipid levels and have a certain protective effect on hepatocytes. Our results suggested that the L. plantarum AR113 alleviated DSS-induced colitis under the Western diet by improving dyslipidemia, repairing intestinal barrier dysfunction, and inhibiting the TLR4/Myd88/TRAF-6/NF-κB inflammatory pathway. However, these changes were not demonstrated in the L. plantarum AR113Δ bsh 1, and therefore, we reasoned that the presence of bsh 1 may play a crucial role in the L. plantarum AR113 exerting its anti-inflammatory function. The relationship between bile salt hydrolase (BSH) and colitis was worthy of further exploration.

Bifidobacteria are representative intestinal probiotics that have extremely high application value in the food and medical fields. However, the lack of molecular biology tools limits the research on functional genes and mechanisms of bifidobacteria. The application of an accurate and efficient CRISPR system to genome engineering can fill the gap in efficient genetic tools for bifidobacteria. In this study, CRISPR system of B. animalis AR668 was established, which successfully knocked out gene 0348 and gene 0208. The influence of different homology arms and fragments on the knockout effect of the system was explored. In addition, the inducible plasmid curing system of bifidobacteria was innovatively established. This study contributes to the genetic modification and functional mechanism analysis of bifidobacteria., (© 2023. The Author(s).)

Lactobacillus salivarius AR809 was isolated from a healthy adult oral cavity with multiple probiotic properties, such as high antimicrobial activity, adhesion to the oral epithelium, resistance to acidic pH, bile, lysozyme, and H 2 O 2 . In this study, to investigate the genetic basis on probiotic potential and identify the functional genes in the strain, the complete genome of strain AR809 was sequenced by Illumina and PacBio platforms. Then comparative genome analysis on 11 strains of Lactobacillus salivarius was performed. The complete genome of AR809 consisted of a circular 1,747,224 bp chromosome with 33.00% GC content and four circular plasmids [pA (247,948 bp), pB (27,292 bp), pC (3349 bp), and pD (2898 bp), respectively]. From among the 1866 protein-coding genes, 130 carbohydrate metabolism-related genes, 18 bacteriocin biosynthesis-related genes, 74 environmental stress-related genes, and a series of adhesion-related genes were identified via clusters of orthologous genes, Koyto Encyclopedia of Genes and Genomes, and carbohydrate-active enzymes annotation. The comparative genome analysis indicated that genomic homology between AR809 and CICC23174 was the highest. In conclusion, the present work provided valuable insights into the gene's function prediction and understanding the genetic basis on adapting to host oropharyngeal-gastrointestinal tract in strain AR809., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Lactiplantibacillus plantarum is an important member of the probiotic family and colonization of the host intestinal is essential for its continued probiotic function. The mechanism of L. plantarum intestinal colonization has not been elucidated until now, an important reason being that the colonization process is influenced by a number of factors. In this study, to confirm the influences of adhesion ability and host intestinal environment on L. plantarum intestinal colonization, knockouts of L. plantarum AR113 mucin genes were constructed using CRISPR/Cas9 gene editing technology, and polyethylene glycol was used to reduce the intestinal flora abundance. The knockout of L. plantarum AR113 mucin genes barely altered the strain's tolerance to acid and bile salts. Notably, the adhesion number of AR113ΔLp_1431ΔLp_2233ΔLp_2792 to HT-29 cells was reduced from 175 to 114 per 100 cells. Through in vivo colonization experiments, an increase in the fluorescence intensity of AR113 and AR113ΔLp_1431&2233&2792 was detected the day after the mice were fed, while the deletion of Lp_1431, Lp_2233 and Lp_2792 genes reduced the intestinal tract colonization time from 14 to 11 days. Both AR113 and AR113ΔLp_1431ΔLp_2233ΔLp_2792 were reproduced in the intestine by labeling with 5-(6)-carboxyfluorescein diacetate N-succinimidyl ester. The results showed that the change in fluorescence intensity was closely dependent on the number of adhesions. Finally, compared to the control group, the prolonged intestinal colonization time of AR113ΔLp_1431ΔLp_2233ΔLp_2792 increased mice intestinal flora abundance, with distributions in the duodenum, jejunum, ileum and colon. Collectively, both the intestinal environment and the adhesion ability of L. plantarum AR113 affected intestinal colonization, and the host's intestinal genetic background may be a key factor in the intestinal colonization of L. plantarum., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: Adhesion is considered important for Lactiplantibacillus to persist in the human gut and for it to exert probiotic effects. Lactiplantibacillus plantarum contains a considerable number and variety of genes encoding bile salt hydrolases (bsh), but their effects on microbial adhesion remain poorly understood. To clarify the effects of four bsh on adhesion, we tried to knock out bsh (Δbsh) of L. plantarum AR113 using the CRISPR-Cas9 method, and compared the growth, auto-aggregation (R AA ), co-aggregation (R CA ), surface hydrophobicity (A HC ) of AR113 wild-type and Δbsh strains and their adhesion abilities to HT29 cells., Results: We first obtained the AR113 Δbsh1,3,2,4 strain with four bsh knocked out. Their growth was significantly slower than the wild-type strain cultured in De Man, Rogosa, and Sharpe medium (MRS) with 3.0 g L -1 glyco- or tauro-conjugated bile acid. Bsh had no significant effect on the growth of ten strains cultured in MRS, but Δbsh1 inhibited their growth when cultured in MRS containing 3.0 g L -1 sodium glycocholate, whereas Δbsh4 instead promoted their growth in MRS with 3.0 g L -1 sodium glycocholate and sodium taurocholate. R CA and R AA were linearly positive for all strains except AR113 Δbsh2,4, and A HC and R AA were negatively correlated for most strains excluding AR113 Δbsh2, with R AA  = 6.38-25.05%, R CA  = 5.17-9.22%, and A CH  = 3.22-47.71%. The adhesion ability of ten strains cultured in MRS was higher than that of strains cultured in MRS with 3.0 g L -1 bovine bile, and it was related to bsh2., Conclusion: Bsh differentially affected the adhesion of AR113 series strains. This adds to the available information about substrate-gene-performance, and provides new information to enable engineering to regulate the colonization of Lactiplantibacillus. © 2021 Society of Chemical Industry., (© 2021 Society of Chemical Industry.)

Probiotics plays an important role in regulating gut microbiota and maintaining intestinal homeostasis. Extracellular vesicles (EVs) derived from probiotics have emerged as potential mediators of host immune response and anti-inflammatory effect. However, the anti-inflammatory effect and mechanism of probiotics derived EVs on inflammatory bowel disease (IBD) remains unclear. In this study, the effect of Lactobacillus plantarum Q7-derived extracellular vesicles (Q7-EVs) on gut microbiota and intestinal inflammation was investigated in C57BL/6J mice. The results showed that Q7-EVs alleviated DSS-induced colitis symptoms, including colon shortening, bleeding, and body weight loss. Consumption of Q7-EVs reduced the degree of histological damage. DSS-upregulated proinflammatory cytokine levels including IL-6, IL-1β, IL-2 and TNF-α were reduced significantly by Q7-EVs ( p < 0.05). 16S rRNA sequencing results showed that Q7-EVs improved the dysregulation of gut microbiota and promoted the diversity of gut microbiota. It was observed that the pro-inflammatory bacteria (Proteobacteria) were reduced and the anti-inflammatory bacteria ( Bifidobacteria and Muribaculaceae ) were increased. These findings indicated that Q7-EVs might alleviate DSS-induced ulcerative colitis by regulating the gut microbiota., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Hao, Zhang, Tong, Liu, Liang, Bu, Gong, Liu, Zhang, Xia, Ai and Yi.)

The probiotic Saccharomyces boulardii has been widely used in colitis treatment; however, the beneficial effects of other yeast species are rarely studied. Saccharomyces cerevisiae with great stress tolerance and potential in colitis treatment was investigated in this study. Among 16 yeast strains, BR14, BR54, and BR174 strains showed good stress-resistant capacity, anti-inflammatory activity, and little toxicity to macrophages. As for the colitis mice, BR14 inhibited weight loss the most, as well as the disease activity index and colon shortening. After treatment with BR14, the expression levels of genes related to histological damage were all upregulated. BR14 significantly attenuated the expression levels of TNF-α and IL-6, while the expression of IL-10 was upregulated. Additionally, BR14 rebalanced the intestinal microbial composition of colitis mice by increasing the abundance of Muribaculaceae , Lactobacillus and Rikenellaceae and decreasing the abundance of Turicibacter , Escherichia-Shigell a, Desulfovibrio , and Lachnospiraceae . In summary, BR14 exhibited great potential in alleviating colitis through restoring the gut barrier and adjusting the intestinal microbiota.

The beneficial effects of probiotics on inflammatory bowel disease (IBD) are well known, although an understanding of colonisation by endogenous and exogenous bacterial strains and the effects on intestinal inflammation remains elusive. In this study, the colonisation of endogenous Lactobacillus reuteri R28 and exogenous Lactobacillus plantarum AR17-1 was investigated in healthy or PEG-treated mice using a 5(6)-carboxyfluorescein diacetate N-succinimidyl ester (cFDA-SE) labelling technique. The effects of these strains on mice with colitis induced by DSS and treated with PEG + DSS were also studied. Endogenous L. reuteri R28 and exogenous L. plantarum AR17-1 exhibited no significant differences in colonisation in healthy mice, whereas after PEG treatment, colonisation of the intestinal mucosa by L. reuteri R28 was greatly enhanced. L. reuteri R28 more effectively reduced diarrhoea caused by PEG, and L. plantarum AR17-1 more effectively reduced the colitis induced by PEG + DSS and downregulated the expression of the pro-inflammatory cytokines TNF-α, IL-1β, and IL-6. These results suggest that endogenous L. reuteri R28 may easily adapt to the intestinal environment, leading to better colonisation, whereas L. plantarum AR17-1 has a stronger inhibitory effect on inflammation. This finding is relevant to the selection of probiotics.

Enterohemorrhagic Escherichia coli (EHEC) is a strain of human pathogenic E. coli bacteria that can cause serious foodborne diseases. Many probiotics have antagonistic effects on EHEC, but few studies have examined the interactions between probiotics and EHEC in vivo. To investigate the colonization of Lactobacillus casei LC2W and its inhibitory effect on E. coli O157:H7 in vivo, these strains labelled with different fluorescent proteins were monitored in the intestinal tracts of live mice using an in vivo imaging system. The results showed that L. casei LC2W inhibited the colonization of O157:H7 in mice. Further research found that LC2W had both prevention and treatment effects on the colitis severity of mice infected by O157:H7, where the prevention effect dominated over the treatment one. This study demonstrates a feasible method for studying the interactions between probiotics and pathogens, and the mechanisms by which probiotics reduce colitis induced by O157:H7.

The objective of this study was to effectively screen out a Lactobacillus strain with excellent adhesion ability and ameliorative effect on the disease symptoms of a murine ulcerative colitis model. The auto-aggregation rate (RAA), co-aggregation rate with Escherichia coli O157 (RCA), and cell surface hydrophobicity (AHC) of 17 Lactobacillus strains were measured for primary selection. The results indicate that Lactobacillus plantarum AR326 displayed the topmost overall aggregation performance among all strains examined. A positive and linear relationship between RCA and RAA values was observed for 15 Lactobacillus strains with RAA = 16-46% and RCA = 15-27%. For adhesion ability to human adenocarcinoma HT-29 cells, five representative Lactobacillus strains showed a good, positive dependence on RAA, where L. plantarum AR326 and L. fermentum AR184 showed a higher adhesion ability than the others. Using the 5 (6)-carboxyfluorescein diacetate N-succinimidyl ester (cFDA SE)-labeling technique, L. plantarum AR326 was confirmed to adhere to and colonize well in the intestinal mucosa of mice mainly in the ileum and colon. Finally, L. plantarum AR326 at the dosage applied (daily 2 × 109 cfu per mouse) could attenuate murine dextran sulfate sodium (DSS)-induced colitis by effectively decreasing the body weight loss, disease activity index, colon length shortening, myeloperoxidase activity, and colon epithelial damage of experimental animals. The protective effects involved the restoration of the tight junction protein expression and reduction of the abnormal expression of pro-inflammatory cytokines. In conclusion, L. plantarum AR326 can be used as promising probiotics to ameliorate DSS-induced colitis.

Lactic acid bacteria (LAB) have been used as ingredients of functional foods to promote health and prevent diseases because of their beneficial effects. This study aimed to investigate the antioxidative effects of LAB on the hepatotoxicity in D-galactose-induced aging mice. LAB were isolated from the traditional Chinese fermented foods and screened by the tolerance of hydrogen peroxide (H 2 O 2 ). Male ICR (Institute of Cancer Research) mice were subcutaneously injected with D-galactose for 5 weeks and then gastric gavage with LAB for 6 weeks. The results showed that Lactobacillus plantarum AR113 and AR501, and Pediococcu pentosaceus AR243 could tolerate up to 1.5 mM H 2 O 2 in vitro, and they could live through simulated gastrointestinal tract (GIT) to colonizing the GIT of host. In vivo, oral administration of L. plantarum AR113 and AR501 improved the antioxidant status of D-galactose-induced oxidative stress mice such as alleviated liver damages and reduced abnormal activities of superoxide dismutase, glutathione peroxidase, and catalase to normal levels. In addition, L. plantarum AR501 markedly elevated the gene expression of nuclear factor erythroid-2-related factor 2 and upregulated the expressions of several antioxidant genes such as glutathione reductase, glutathione S-transferase, glutamate-cysteine ligase catalytic subunit, glutamate-cysteine ligase modifier subunit, and NAD(P)H quinone oxidoreductase 1 in the liver of an aging mice. Therefore, L. plantarum AR501 could be a good candidate for producing antiaging functional foods., (© 2018 Institute of Food Technologists®.)

AbstractType 2 diabetes mellitus (T2DM) is one of the metabolic diseases with the highest morbidity rates in the world. Probiotics have positive health impacts on human health and a considerable amount of research has demonstrated their beneficial effects in treating T2DM. However, probiotic intervention in T2DM has complex mechanisms because the pathogenesis of T2DM is complex. This review summarized the mechanisms of probiotic intervention in diabetes from the perspective of diabetes pathogenesis. First, the objectives of probiotic intervention in diabetes aimed at the intestinal tract reparative effects, pancreatic function, host metabolism and self-recovery were comprehensively reviewed. Next, we concluded the clinical application status of ingested probiotics in patients with T2DM, and an obvious imbalance exists between theoretical probiotic research and clinical applications. Finally, we summarized the emerging research on probiotic interventions in T2DM and analyzed the literature in this regard, including next-generation probiotics; suggestions for probiotics consumption with the aim of diabetic complications; as well as the association between novel mechanisms of diabetes remission with the potential for probiotic intervention. In conclusion, this review sheds light on the potential role of probiotics, from proposed mechanisms to prospects in relieving T2DM. [ABSTRACT FROM AUTHOR]

Hyperlipidemia significantly increases the risk of cardiovascular disease, and the number of patients is gradually increasing and tends to be younger. The prevalence factors and pathogenesis of hyperlipidemia are the hotspots of current research. Research has shown that abnormal blood lipids are closely related to gut microbiota and dietary habits. We investigated the association between gut microbiota typing and lipid indices in hyperlipidemic patients by 16s rRNA and resolved the differences with gut microbiota in healthy populations, and compared the experimental results using Meta-analysis. The results displayed that the gut microbiota of hyperlipidemic patients could be classified into two enterotypes (Bac and Bla) and there was a significant difference such as Faecalibacterium , Bacteroides , and Agathobacter between the two groups. There was a high similarity in the composition of gut microbiota between Bac enterotype patients and healthy individuals, and the TG levels of the patients in the Bac group were also less different from those of the healthy population. However, the relative abundance of Faecalibacterium and Bacteroides was lower appreciably in patients with Bla enterotypes compared to patients with Bac enterotypes and healthy populations, suggesting that TG levels may influence changes in gut microbiota. Furthermore, the results of Mate-analysis did not reveal a significant correlation between Bacteroides and TG, whereas this study has detected a negative correlation between the abundance of Bacteroides and TG content. And the changes in Faecalibacterium abundance in the gut microbiota of hyperlipidemic patients and healthy people in this cohort population were consistent with the results of Meta-analysis. Therefore, they may be potential strains for the treatment of hyperlipidemia caused by elevated TG. [Display omitted] [ABSTRACT FROM AUTHOR]

The probiotics market is one of the fastest growing segments of the food industry as there is growing scientific evidence of the positive health effects of probiotics on consumers. Currently, there are various forms of probiotic products and they can be categorized according to dosage form and the site of action. To increase the effectiveness of probiotic preparations, they need to be specifically designed so they can target different sites, such as the oral, upper respiratory or gastrointestinal tracts. Here we review the characteristics of different dosage forms of probiotics and discuss methods to improve their bioavailability in detail, in the hope that this article will provide a reference for the development of probiotic products. [ABSTRACT FROM AUTHOR]

Bifidobacterium can be used as probiotic that confers various health benefits to its host. The functional analysis of specific genes can help elucidate the probiotic mechanism of Bifidobacterium. However, the low transformation efficiency has hindered the in-depth study of its function by genetic manipulation. In this study, we optimized transformation methods for Bifidobacterium animalis AR668 to improve the transformation efficiency up to 2.15 ×105 CFU/μg DNA. Additionally, the expression of competence gene ssb2 could enhance the transformability which was the first attempt to apply it to B. animalis. Moreover, the transformation efficiency was increased after the plasmids were modified by gene0033 and gene1509 which limited the interference of the restriction-modification system in the uptake of foreign DNA by cells. Based on the above optimization, the transformation efficiency of 7.2 ×105 CFU/μg DNA for AR668 was obtained, which was more than 100 times higher than that of the original condition. Together, we successfully improved the transformation efficiency of B. animalis AR668, contributing to its genetic manipulation and modification. [ABSTRACT FROM AUTHOR]

The gut microbiota plays a vital role in human health. Many studies have shown that an imbalance of in the intestinal flora not only can cause intestinal diseases; but also is closely related to obesity, diabetes and other chronic metabolic diseases. Probiotics are defined as live microorganisms, that can colonize the human intestinal tract to improve the microbiological balance and migigate diabetes and other metabolic diseases. Therefore, approaches that aim to target the intestinal flora and thus alleviate diabetes have unique advantages, although the underlying mechanisms are complex and diverse. From this perspective, this review summarize here the relationship between the intestinal flora, probiotics and diabetes. Particularly, it focuses on the mechanism by which probiotics relieve diabetes by targeting the intestinal microbiota from the aspects of oxidative stress, immune responses, amino acid metabolism, intestinal permeability and short-chain fatty acids. [ABSTRACT FROM AUTHOR]

In recent years, potential probiotic strains have been increasingly applied to food to promote consumer health or improve the nutrition of products. In current study, a potential probiotic Saccharomyces cerevisiae strain BR14 was applied for the development of functional Huangjiu. The strain significantly increased the ethanol content in final wine, as well as the total acidity, especially acetic acid and lactic acid. As an accessory starter, BR14 promoted the formation of total volatile flavor compounds, particularly in 1-propanol, 3-methyl-1-butanol and phenethyl alcohol. Meanwhile, it reduced the formation of 2-Methyl-1-propanol by 54.65%. Regarding nutrients and functionality of final Chinese rice wine, S. cerevisiae BR14 exhibited excellent capacity in the improvement of glutamic acid, ornithine and antiradical activity for wine production. Content of urea, which determined the formation of ethyl carbamate, considerably decreased by the co-fermentation of BR14. Moreover, polysaccharide of Huangjiu fermented by BR14 stimulated the proliferation of macrophages RAW264.7, and reduced anti-inflammatory response. Based on sensory evaluation, BR14 wine was highly assessed for its intensive levels in alcohol-aroma and full body. This study verified the biofunctions of BR14, indicating the possibility to apply potential probiotic yeasts in food applications. • A potential probiotic yeast strain BR14 was used to develop functional Huangjiu. • BR14 greatly contributed to the improvement of organic acids and aromatic alcohols. • BR14 reduced the content of urea and 2-methyl-1-propanol. • BR14 enhanced content of non-essential amino acids (Glu and Orn). • BR14 improved the healthy characteristics of rice wine. [ABSTRACT FROM AUTHOR]