Biogenic amine tryptamine in human vaginal probiotic isolates mediates matrix inhibition and thwarts uropathogenic E. coli biofilm.

Probiotics offer a promising prophylactic approach against various pathogens and represent an alternative strategy to combat biofilm-related infections. In this study, we isolated vaginal commensal microbiota from 54 healthy Indian women to investigate their probiotic traits. We primarily explored the ability of cell-free supernatant (CFS) from Lactobacilli to prevent Uropathogenic Escherichia coli (UPEC) colonization and biofilm formation. Our findings revealed that CFS effectively reduced UPEC's swimming and swarming motility, decreased cell surface hydrophobicity, and hindered matrix production by downregulating specific genes (fimA, fimH, papG, and csgA). Subsequent GC-MS analysis identified Tryptamine, a monoamine compound, as the potent bioactive substance from Lactobacilli CFS, inhibiting UPEC biofilms with an MBIC of 4 µg/ml and an MBEC of 8 µg/ml. Tryptamine induced significant changes in E. coli colony biofilm morphology, transitioning from the Red, Dry, and Rough (RDAR) to the Smooth and White phenotype, indicating reduced extracellular matrix production. Biofilm time-kill assays demonstrated a four-log reduction in UPEC viability when treated with Tryptamine, highlighting its potent antibacterial properties, comparable to CFS treatment. Biofilm ROS assays indicated a significant elevation in ROS generation within UPEC biofilms, suggesting a potential antibacterial mechanism. Gene expression studies with Tryptamine-treated samples showed a reduction in expression of curli gene (csgA), consistent with CFS treatment. This study underscores the potential of Tryptamine from probiotic Lactobacilli CFS as a promising antibiofilm agent against UPEC biofilms.

Mangosteen extracts: Effects on intestinal bacteria, and application to functional fermented milk products.

Mangosteen (Garcinia mangostana L.) is a tasty, polyphenol-rich tropical fruit. The edible part is highly appreciated by its aroma, taste and texture. The non-edible part, rich in polyphenols, has been traditionally used in Thai medicine. In this work, flavonoids and phenolic acid/derivatives were identified in mangosteen extracts (ME) from edible and non-edible portions. We first studied the effects of MEs on the growth, metabolism, antioxidant capacity, biofilm formation and antimicrobial capacity of eight bifidobacteria and lactobacilli strains from intestinal origin and two commercial probiotic strains (BB536 and GG). ME concentrations higher than 10-20 % were inhibitory for all strains. However, ME concentrations of 5 % significantly (P < 0.01) increased all strains antioxidant capacity, reduced biofilm-formation, and enhanced inhibition against Gram-positive pathogens. To apply these knowledge, bifunctional fermented milk products were elaborated with 5 % ME and individual strains, which were selected taking into account their growth with ME, and the widest range of values on antioxidant capacity, biofilm formation and antimicrobial activity (bifidobacteria INIA P2 and INIA P467, lactobacilli INIA P459 and INIA P708, and reference strain GG). Most strains survived well manufacture, refrigerated storage and an in vitro simulation of major conditions encountered in the gastrointestinal tract. As expected, products supplemented with ME showed higher polyphenol content and antioxidant capacity levels than control. After sensory evaluation, products containing strains INIA P2, INIA P708 and GG outstood as best.

Postbiotic mediators derived from Lactobacillus species enhance riboflavin-mediated antimicrobial photodynamic therapy for eradication of Streptococcus mutans planktonic and biofilm growth.

BACKGROUND: Streptococcus mutans has been implicated as a primary causative agent of dental caries and one of its important virulence properties is an ability to form biofilm on tooth surfaces. Thus, strategies to prevent and control S. mutans biofilms are requested. The present study aimed to examine the eradication of S. mutans planktonic and biofilm cells using riboflavin (Rib)-mediated antimicrobial photodynamic therapy (aPDT) enhanced by postbiotic mediators derived from Lactobacillus species. MATERIALS AND METHODS: Minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of Rib and postbiotic mediators were determined. The antimicrobial and anti-biofilm effects of Rib-mediated aPDT (Rib plus blue light), Rib-mediated aPDT in combination with postbiotic mediators derived from Lactobacillus casei (LC) (aPDT+ LC), and Rib-mediated aPDT in combination with postbiotic mediators derived from Lactobacillus plantarum (LP) (aPDT+ LP) were evaluated. The anti-virulence potential of Rib-mediated aPDT, aPDT+ LC, and aPDT+ LP were assessed by measuring the expression of the gtfB gene using quantitative real-time polymerase chain reaction (qRT-PCR) at the highest concentrations of Rib, LC, and LP, at which the S. mutans had proliferation as the same as in the control (non-treated) group. RESULTS: According to the results, the MIC doses of LC, LP, and Rib were 64 µg/mL, 128 µg/mL, and 128 µg/mL, respectively, while the MBC values of LC, LP, and Rib were 128 µg/mL, 256 µg/mL, and 256 µg/mL, respectively. Rib-mediated aPDT, aPDT+ LP, and aPDT+ LC showed a significant reduction in Log10 CFU/mL of S. mutans compared to the control group (4.2, 4.9, and 5.2 Log10 CFU/mL, respectively; all P < 0.05). The most destruction of S. mutans biofilms was observed after treatment with aPDT+ LC followed by aPDT+ LP and Rib-mediated aPDT (77.5%, 73.3%, and 67.6%, respectively; all P < 0.05). The concentrations of 31.2 µg/mL, 62.5 µg/mL, and 62.5 µg/mL were considered as the highest concentrations of LC, LP, and Rib, respectively, at which S. mutans replicates as same as the control group and were used for gtfB gene expression assay using qRT-PCR during Rib-mediated aPDT, aPDT+ LP, and aPDT+ LC treatments. Gene expression results revealed that aPDT+ LP and aPDT+ LC could decrease the gene expression level of gtfB by 6.3- and 5.7-fold, respectively (P < 0.05), while only 5.1-fold reduction was observed after Rib-mediated aPDT (P < 0.05). CONCLUSION: Our findings indicate that aPDT+ LP and aPDT+ LC hold promise for use as a treatment to combat S. mutans planktonic and biofilms growth as well as anti-virulence as a preventive strategy to inhibit biofilms development via reduction of gtfB gene expression.

Astragalus Polysaccharide Modulates the Gut Microbiota and Metabolites of Patients with Type 2 Diabetes in an In Vitro Fermentation Model.

This study investigated the effect of astragalus polysaccharide (APS, an ingredient with hypoglycemic function in a traditional Chinese herbal medicine) on gut microbiota and metabolites of type 2 diabetes mellitus (T2DM) patients using a simulated fermentation model in vitro. The main components of APS were isolated, purified, and structure characterized. APS fermentation was found to increase the abundance of Lactobacillus and Bifidobacterium and decrease the Escherichia-Shigella level in the fecal microbiota of T2DM patients. Apart from increasing propionic acid, APS also caused an increase in all-trans-retinoic acid and thiamine (both have antioxidant properties), with their enrichment in the KEGG pathway associated with thiamine metabolism, etc. Notably, APS could also enhance fecal antioxidant properties. Correlation analysis confirmed a significant positive correlation of Lactobacillus with thiamine and DPPH-clearance rate, suggesting the antioxidant activity of APS was related to its ability to enrich some specific bacteria and upregulate their metabolites.

Lactobacilli decrease the susceptibility of Salmonella Typhimurium to azithromycin.

Bacteria are involved in numerous interactions during infection and among host-associated microbial populations. Salmonella enterica serovar Typhimurium is a foodborne pathogen of great importance as well as a model organism to study interactions within a microbial community. In this study, we found that S. Typhimurium becomes tolerant to azithromycin when co-cultured with lactobacilli strains. Similarly, acidified media, from cell-free supernatant of lactobacilli cultures for instance, also induced the tolerance of S. Typhimurium to azithromycin. The addition of membrane disruptors restored the normal sensitivity to azithromycin in acidified media, but not when lactobacilli were present. These results suggested that the acidification of the media led to modification in envelope homeostasis, but that a different mechanism promoted the tolerance to azithromycin in the presence of lactobacilli strains. To further understand how lactobacilli strains modify the sensitivity of S. Typhimurium to azithromycin, a high-throughput assay was performed using the single-gene deletion collection of the S. Typhimurium (1) in co-culture with Lacticaseibacillus rhamnosus and (2) in sterile acidic conditions (pH 5.5 media only). As expected, both screens identified genes involved in envelope homeostasis and membrane permeability. Our results also suggest that changes in the metabolism of S. Typhimurium induce the tolerance observed in the presence of L. rhamnosus. Our results thus highlight two different mechanisms by which lactobacilli induce the tolerance of S. Typhimurium to azithromycin.IMPORTANCEThis study provides valuable insights into the intricate interactions between bacteria during infections and within host-associated microbial communities. Specifically, it sheds light on the significant role of lactobacilli in inducing antibiotic tolerance in Salmonella enterica serovar Typhimurium, a critical foodborne pathogen and model organism for microbial community studies. The findings not only uncover the mechanisms underlying this antibiotic tolerance but also reveal two distinct pathways through which strains of lactobacilli might influence Salmonella's response to antibiotics. Understanding these mechanisms has the potential to enhance our knowledge of bacterial infections and may have implications for the development of strategies to combat antibiotic resistance in pathogens, such as Salmonella. Furthermore, our results underscore the necessity to explore beyond the direct antimicrobial effects of antibiotics, emphasizing the broader microbial community context.

Heterologous expression and antimicrobial potential of class II bacteriocins.

Gut bacteria are known to produce bacteriocins to inhibit the growth of other bacteria. Consequently, bacteriocins have attracted increased attention as potential microbiome-editing tools. In this study we examine the inhibitory spectrum of 75 class II bacteriocins against 48 representative gut microbiota species. The bacteriocins were heterologously expressed in Escherichia coli and evaluated in vitro, ex vivo and in vivo. In vitro assays revealed 22 bacteriocins to inhibit at least one species and showed selective inhibition patterns against species implicated in certain disorders and diseases. Three bacteriocins were selected for ex vivo assessment on mouse feces. Based on 16S rRNA sequencing of the cultivated feces we showed that the two bacteriocins: Actifencin (#13) and Bacteroidetocin A (#22) selectively inhibited the growth of Lactobacillus and Bacteroides, respectively. The probiotic: E. coli Nissle 1917 was engineered to express these two bacteriocins in mice. However, the selective inhibitory patterns found in the in vitro and ex vivo experiments could not be observed in vivo. Our study describes a methodology for heterologous high throughput bacteriocin expression and screening and elucidates the inhibitory patterns of class II bacteriocins on the gut microbiota.

In vitro effect of TiF4/NaF solution on the development of radiation-induced dentin caries.

OBJECTIVE: To evaluate the protective effect of an experimental solution containing TiF4/NaF on the development of radiation-induced dentin caries lesions. METHODOLOGY: bovine root samples were irradiated (70Gy) and distributed as following (n=12/group): Commercial Saliva (BioXtra), NaF (500 ppm F-), TiF4 (500 ppm F), TiF4/NaF (TiF4: 300 ppm F-, NaF: 190 ppm F-), and Phosphate buffer solution (PBS, negative control). Biofilm was produced using biofilm from irradiated patients and McBain saliva (0.2% of sucrose, at 37oC and 5% CO2) for five days. The treatments were applied 1x/day. Colony-forming units (CFU) were counted and demineralization was quantified by transversal microradiography. The ANOVA/Tukey test was applied for all parameters. RESULTS: All treatments reduced CFU for total microorganisms. TiF4 reduced Lactobacillus sp. (7.04±0.26 log10 CFU/mL) and mutans streptococci (7.18±0.28) CFU the most, when compared to PBS (7.58±0.21 and 7.75±0.17) and followed by NaF (7.12±0.31 and 7.34±0.22) and TiF4/NaF (7.16±0.35 and 7.29± 0.29). TiF4 and Commercial saliva showed the lowest integrated mineral loss (ΔZ-vol%.mm) (1977±150 and 2062±243, respectively) when compared to PBS (4540±335), followed by NaF (2403±235) and TiF4/NaF (2340±200). Commercial saliva was the only to significantly reduce mineral loss (LD-µm) (111±25) compared to PBS (153±24).Mean mineral loss (R-vol%) decreased by 35.2% for TiF4 (18.2±3.3) when compared to PBS (28.1±2.9) Conclusion: TiF4/NaF has a comparable anti-cariogenic effect to TiF4 and Commercial saliva under the model in this study.

Phosphate Uptake and Its Relation to Arsenic Toxicity in Lactobacilli.

The use of probiotic lactobacilli has been proposed as a strategy to mitigate damage associated with exposure to toxic metals. Their protective effect against cationic metal ions, such as those of mercury or lead, is believed to stem from their chelating and accumulating potential. However, their retention of anionic toxic metalloids, such as inorganic arsenic, is generally low. Through the construction of mutants in phosphate transporter genes (pst) in Lactiplantibacillus plantarum and Lacticaseibacillus paracasei strains, coupled with arsenate [As(V)] uptake and toxicity assays, we determined that the incorporation of As(V), which structurally resembles phosphate, is likely facilitated by phosphate transporters. Surprisingly, inactivation in Lc. paracasei of PhoP, the transcriptional regulator of the two-component system PhoPR, a signal transducer involved in phosphate sensing, led to an increased resistance to arsenite [As(III)]. In comparison to the wild type, the phoP strain exhibited no differences in the ability to retain As(III), and there were no observed changes in the oxidation of As(III) to the less toxic As(V). These results reinforce the idea that specific transport, and not unspecific cell retention, plays a role in As(V) biosorption by lactobacilli, while they reveal an unexpected phenotype for the lack of the pleiotropic regulator PhoP.

Synergistic Inhibition of Synbiotic Cultures among Lactobacilli and Plant Extracts against Vaginal Discharge Causing Candida albicans.

Vulvovaginal candidiasis (VVC) is the most common cause of vaginal discharge among women. The present study aimed to investigate the synergistic anticandidal effect of lactobacillus cultures supplemented with plant extracts. Among 600 isolates of lactic acid bacteria, 41 isolates exhibited inhibitory activity against Candida albicans ATCC10231. Six out of 41 cell-free supernatants demonstrated the most potent antibacterial and anticandidal activities. They also inhibited the clinical isolates of C. albicans, causing VVC and non-C. albicans. The synergistic effect between Lactobacillus crispatus 84/7 and Limosilactobacillus reuteri 89/4 was demonstrated by the lowest fractional inhibitory concentration index (FICI = 0.5). The synbiotic culture of bacterial combination, cultured with Jerusalem artichoke (H. tuberosus) extract, also exhibited the strongest inhibition against the tested C. albicans. Biofilm formation decreased after 12 h of incubation in the selected cell-free supernatants of this synbiotic culture. The anticandidal activity of crude extracts was lost after treatment with proteinase K and trypsin but not with heating conditions, suggesting that it may be a heat-stable substance. In conclusion, the combination of L. crispatus 84/7 and L. reuteri 89/4 with H. tuberosus may be a promising candidate for inhibiting Candida infection and biofilm formation, with the potential use as ingredients in vaginal biotherapeutic products.

Reduction of microorganisms in carious dentin by photodynamic therapy mediated by potassium iodide added to methylene blue and red laser.

OBJECTIVE: To evaluate the effect of the association of potassium iodide to antimicrobial photodynamic therapy on human carious dentin produced with a microcosm biofilm model. METHODS: A microcosm biofilm model was used to generate a caries lesion on human dentin. Pooled human saliva diluted with glycerol was used as an inoculum on specimens immersed on McBain artificial saliva enriched with 1 % sucrose (24 h at 37 °C in 5 % CO2). After refreshing culture media for 7 days, the dentin specimens were divided in 5 groups (3 specimens per group, in triplicate; n = 9): C (NaCl 0.9 %), CX (2 % chlorhexidine), PKI (0.01 % methylene blue photosensitizer+50 mM KI), L (laser at 15 J, 180 s, 22.7 J/cm2), and PKIL (methylene blue + KI + Laser). After the treatments, dentin was collected, and a 10-fold serial dilution was performed. The number of total microorganisms, total lactobacilli, total streptococci, and Streptococcus mutans was analyzed by microbial counts (CFU/mL). After normality and homoscedasticity analysis, the Welch's ANOVA and Dunnett's tests were used for CFU. All tests used a 5 % significance level. RESULTS: CX and PKIL groups showed significant bacterial decontamination of dentin, compared to group C (p < 0.05) reaching reductions up to 3.8 log10 for CX for all microorganisms' groups and PKIL showed 0.93, 1.30, 1.45, and 1.22 log10 for total microorganisms, total lactobacilli, total streptococci, and S. mutans, respectively. CONCLUSION: aPDT mediated by the association of KI and methylene blue with red laser reduced the viability of microorganisms from carious dentin and could be a promising option for cavity decontamination.

Shexiang Baoxin Pill enriches Lactobacillus to regulate purine metabolism in patients with stable coronary artery disease.

BACKGROUND: It has been clinically confirmed that the Shexiang Baoxin Pill (SBP) dramatically reduces the frequency of angina in patients with stable coronary artery disease (SCAD). However, potential therapeutic mechanism of SBP has not been fully explored. PURPOSE: The study explored the therapeutic mechanism of SBP in the treatment of SCAD patients. METHODS: We examined the serum metabolic profiles of patients with SCAD following SBP treatment. A rat model of acute myocardial infarction (AMI) was established, and the potential therapeutic mechanism of SBP was explored using metabolomics, transcriptomics, and 16S rRNA sequencing. RESULTS: SBP decreased inosine production and improved purine metabolic disorders in patients with SCAD and in animal models of AMI. Inosine was implicated as a potential biomarker for SBP efficacy. Furthermore, SBP inhibited the expression of genes involved in purine metabolism, which are closely associated with thrombosis, inflammation, and platelet function. The regulation of purine metabolism by SBP was associated with the enrichment of Lactobacillus. Finally, the effects of SBP on inosine production and vascular function could be transmitted through the transplantation of fecal microbiota. CONCLUSION: Our study reveals a novel mechanism by which SBP regulates purine metabolism by enriching Lactobacillus to exert cardioprotective effects in patients with SCAD. The data also provide previously undocumented evidence indicating that inosine is a potential biomarker for evaluating the efficacy of SBP in the treatment of SCAD.

Antimicrobial activity of Southern African medicinal plants on Helicobacter pylori and Lactobacillus species.

ETHNOPHARMACOLOGICAL RELEVANCE: Numerous medicinal plants have been used traditionally in South Africa for gastric ulcer treatment. Helicobacter pylori is known for causing inflammation and the onset of gastric ulcers. While several studies explored medicinal plants against H. pylori, investigation of medicinal plants used for gastric ulcers has been neglected, as well as the effects these plants would have on bacteria occurring naturally in the gut microbiome. AIM OF THE STUDY: This study aimed to investigate Southern African medicinal plants used traditionally for treating gastric ulcers against H. pylori , as well as the effects that these plants have when combined with Lactobacillus species and tested against H. pylori. METHODOLOGY: Based on evidence from the ethnobotanical literature, 21 plants were collected. Their antimicrobial activity was assessed against five clinical H. pylori strains, and in combination with each of three Lactobacillus species, using the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) broth microdilution assays. Toxicity was assessed using the brine shrimp lethality assay. RESULTS: Noteworthy activity was observed against at least one H. pylori strain for 12 plant species. The lowest mean MICs were from organic extracts of Carissa edulis Vahl (0.18 mg/mL) and Chironia baccifera L. (0.20 mg/mL), and aqueous extracts of Sansevieria hyacinthoides (L.) Druce (0.26 mg/mL) and Dodonaea viscosa Jacq. (0.30 mg/mL). Aqueous extracts of the investigated plants were combined with Lactobacillus species, and the majority of combinations showed increased antimicrobial activity compared with the extracts alone. Combinations of Lactobacillus rhamnosus with 18 of the 21 aqueous plant extracts showed at least a two-fold decrease in the mean MBC against all H. pylori strains tested. Lactobacillus acidophilus combined with either Protea repens L., Carpobrotus edulis (L.) L. Bolus or Warburgia salutaris (Bertol.f.) Chiov. aqueous extracts had the best anti-H. pylori activity (mean MBCs of 0.10 mg/mL for each combination). Only four organic and one aqueous extract(s) were considered toxic. CONCLUSION: These results highlight the potential of medicinal plants to inhibit H. pylori growth and their role in traditional treatments for the management of ulcers. The results also indicate that aqueous extracts of these plants do not hinder the growth of bacteria that occur naturally in the gut microbiome and play a role in maintaining gut health, as well as show the potential benefit of including Lactobacillus species as potentiators of H. pylori activity.

Gut Microbiota Mediates Lactobacillus rhamnosus GG Alleviation of Deoxynivalenol-Induced Anorexia.

Deoxynivalenol (DON) is a widespread mycotoxin and causes anorexia and emesis in humans and animals; Lactobacillus rhamnosus GG (LGG), a well-characterized probiotic, can improve intestinal barrier function and modulate immune response. Currently, it is unclear whether LGG has a beneficial effect on DON-induced anorexia. In the present study, mice were treated with DON, LGG, or both by gavage for 28 days to evaluate the effects of LGG on DON-induced anorexia. Antibiotic treatment and fecal microbiota transplant (FMT) experiment were also conducted to investigate the link between DON, LGG, and gut microbiota. LGG significantly increased the villus height and reduced the crypt depth in jejunum and ileum, enhanced the tight junction proteins expression in the intestine, and regulated the TLR4/NF-κB signaling pathway, consequently attenuating the intestinal inflammation caused by DON. In addition, LGG increased the relative abundance of Lactobacillus and butyric acid production of cecal contents; remodeled phenylalanine metabolism and tryptophan metabolism; reduced plasma peptide tyrosine tyrosine (PYY), 5-hydroxytryptamine (5-HT), and glucagon-like peptide-1 (GLP-1) concentrations; and promoted hypothalamic NPY and AgPR gene expression, which will further promote food intake and reduce weight loss, ultimately alleviating DON-induced anorexia in mice. Interestingly, antibiotic treatment diminished the intestinal toxicity of DON. The FMT experiment showed that DON-originated microbiota promotes intestinal inflammation and anorexia, while LGG + DON-originated microbiota has no adverse effects on mice. Both antibiotic treatment and FMT experiment have proved that gut microbiota was the primary vector for DON to exert its toxic effects and an essential mediator of LGG protection. In summary, our findings demonstrate that gut microbiota plays essential roles in DON-induced anorexia, and LGG can reduce the adverse effects caused by DON through its structure and regulate the gut microbiota, which may lay the important scientific foundation for future applications of LGG in food and feed products.

Antimicrobial plant secondary metabolites, MDR transporters and antimicrobial resistance in cereal-associated lactobacilli: is there a connection?

Cereal-associated lactobacilli resist antimicrobial plant secondary metabolites. This study aimed to identify multi-drug-resistance (MDR) transporters in isolates from mahewu, a Zimbabwean fermented cereal beverage, and to determine whether these MDR-transporters relate to resistance against phenolic compounds and antibiotics. Comparative genomic analyses indicated that all seven mahewu isolates harbored multiple MATE and MFS MDR proteins. Strains of Lactiplantibacillus plantarum and Limosilactobacillus fermentum encoded for the same gene, termed mahewu phenolics resistance gene mprA, with more than 99% nucleotide identity, suggesting horizontal gene transfer. Strains of Lp. plantarum were more resistant than strains of Lm. fermentum to phenolic acids, other antimicrobials and antibiotics but the origins of strains were not related to resistance. The resistance of several strains exceeded EFSA thresholds for several antibiotics. Analysis of gene expression in one strain each of Lp. plantarum and Lm. fermentum revealed that at least one MDR gene in each strain was over-expressed during growth in wheat, sorghum and millet relative to growth in MRS5 broth. In addition, both strains over-expressed a phenolic acid reductase. The results suggest that diverse lactobacilli in mahewu share MDR transporters acquired by lateral gene transfer, and that these transporters mediate resistance to secondary plant metabolites and antibiotics.

Impact of vaginal douching products on vaginal Lactobacillus, Escherichia coli and epithelial immune responses.

We compared the effect of commercial vaginal douching products on Lactobacillus crispatus, L. jensenii, L. gasseri, L. iners, E. coli, and immortalized vaginal epithelial cells (VK2). All studied douching products (vinegar, iodine and baking soda based) induced epithelial cell death, and all inhibited growth of E. coli. Co-culture of vaginal epithelial cells with any of the lactobacilli immediately following exposure to douching products resulted in a trend to less human cell death. However, co-culture of epithelial cells with L. iners was associated with higher production of IL6 and IL8, and lower IL1RA regardless of presence or type of douching solution. Co-culture with L. crispatus or L. jensenii decreased IL6 production in the absence of douches, but increased IL6 production after exposure to vinegar. Douching products may be associated with epithelial disruption and inflammation, and may reduce the anti-inflammatory effects of beneficial lactobacilli.

Serum Untargeted Metabolism Reveals the Mechanism of L. plantarum ZDY2013 in Alleviating Kidney Injury Induced by High-Salt Diet.

A high-salt diet (HSD) is one of the key risk factors for hypertension and kidney injury. In this study, a HSD C57BL/6J mice model was established with 4% NaCl, and then different concentrations of Lactobacillus plantarum ZDY2013 were intragastrically administered for 2 weeks to alleviate HSD-induced renal injury. For the study, 16S rRNA gene sequencing, non-targeted metabonomics, real-time fluorescent quantitative PCR, and Masson's staining were used to investigate the mechanism of L. plantarum ZDY2013 in alleviating renal damage. Results showed that HSD caused intestinal inflammation and changed the intestinal permeability of mice, disrupted the balance of intestinal flora, and increased toxic metabolites (tetrahydrocorticosteron (THB), 3-methyhistidine (3-MH), creatinine, urea, and L-kynurenine), resulting in serious kidney damage. Interestingly, L. plantarum ZDY2013 contributed to reconstructing the intestinal flora of mice by increasing the level of Lactobacillus and Bifidobacterium and decreasing that of Prevotella and Bacteroides. Moreover, the reconstructed intestinal microbiota significantly changed the concentration of the metabolites of hosts through metabolic pathways, including TCA cycle, ABC transport, purine metabolism, and histidine metabolism. The content of uremic toxins such as L-kynurenine, creatinine, and urea in the serum of mice was found to be decreased by L. plantarum ZDY2013, which resulted in renal injury alleviation. Our data suggest that L. plantarum ZDY2013 can indeed improve chronic kidney injury by regulating intestinal flora, strengthening the intestinal barrier, limiting inflammatory response, and reducing uremic toxins.

Biological Transformation of Zearalenone by Some Bacterial Isolates Associated with Ruminant and Food Samples.

Zearalenone (ZEA) is a secondary metabolite produced by Fusarium spp., the filamentous fungi. Food and feed contamination with zearalenone has adverse effects on health and economy. ZEA degradation through microorganisms is providing a promising preventive measure. The current study includes isolation of 47 bacterial strains from 100 different food and rumen samples. Seventeen isolates showed maximum activity of ZEA reduction. A bacterial isolate, RS-5, reduced ZEA concentration up to 78.3% through ELISA analysis and 74.3% as determined through HPLC. Ten of the most efficient strains were further selected for comparison of their biodegradation activity in different conditions such as incubation period, and different growth media. The samples were analyzed after 24 h, 48 h, and 72 h of incubation. De Man Rogosa Sharp (MRS) broth, Tryptic soy broth, and nutrient broth were used as different carbon sources for comparison of activity through ELISA. The mean degradation % ± SD through ELISA and HPLC were 70.77% ± 3.935 and 69.11% ± 2.768, respectively. Optimum reducing activity was detected at 72 h of incubation, and MRS broth is a suitable medium. Phylogenetic analysis based on 16S rRNA gene nucleotide sequences confirmed that one of the bacterial isolate RS-5 bacterial isolates with higher mycotoxin degradation is identified as Bacillus subtilis isolated from rumen sample. B05 (FSL-8) bacterial isolate of yogurt belongs to the genus Lactobacillus with 99.66% similarity with Lactobacillus delbrukii. Similarly, three other bacterial isolates, D05, H05 and F04 (FS-17, FSL-2 and FS-20), were found to be the sub-species/strains Pseudomonas gessardii of genus Pseudomonas based on their similarity level of (99.2%, 96% and 96.88%) and positioning in the phylogenetic tree. Promising detoxification results were revealed through GC-MS analysis of RS-5 and FSL-8 activity.

Hernandulcin Production in Cell Suspensions of Phyla Scaberrima: Exploring Hernandulcin Accumulation through Physical and Chemical Stimuli.

Hernandulcin (HE) is a non-caloric sweetener synthesized by the Mexican medicinal plant Phyla scaberrima. Herein we present the results of HE production through cell suspensions of P. scaberrima as well as the influence of pH, temperature, biosynthetic precursors and potential elicitors to enhance HE accumulation. The incorporation of mevalonolactone (30-400 mg L-1 ) farnesol (30-400 mg L-1 ), AgNO3 (0.025-0.175 M), cellulase (5-60 mg L-1 ; 0.3 units/mg), chitin (20-140 mg L-1 ) and (+)-epi-α-bisabolol (300-210 mg L-1 ) to the cell suspensions, resulted in a differential accumulation of HE and biomass. Among elicitors assayed, chitin, cellulase and farnesol increased HE production from 93.2 to ∼160 mg L-1 but, (+)-epi-α-bisabolol (obtained by a synthetic biology approach) increased HE accumulation up to 182.7 mg L-1 . HE produced by the cell suspensions was evaluated against nine strains from six species of gastrointestinal bacteria revealing moderate antibacterial activity (MIC, 214-465 µg mL-1 ) against Staphylococcus aureus, Escherichia coli and Helicobacter pylori. Similarly, HE showed weak toxicity against Lactobacillus sp. and Bifidobacterium bifidum (>1 mg mL-1 ), suggesting a selective antimicrobial activity on some species of gut microbiota. According to our results, chitin and (+)-epi-α-bisabolol were the most effective molecules to enhance HE accumulation in cell suspensions of P. scaberrima.

Immunosuppressive activity is attenuated by Astragalus polysaccharides through remodeling the gut microenvironment in melanoma mice.

Astragalus polysaccharides (APS), the main effective component of Astragalus membranaceus, can inhibit tumor growth, but the underlying mechanisms remain unclear. Previous studies have suggested that APS can regulate the gut microenvironment, including the gut microbiota and fecal metabolites. In this work, our results showed that APS could control tumor growth in melanoma-bearing mice. It could reduce the number of myeloid-derived suppressor cells (MDSC), as well as the expression of MDSC-related molecule Arg-1 and cytokines IL-10 and TGF-ß, so that CD8+ T cells could kill tumor cells more effectively. However, while APS were administered with an antibiotic cocktail (ABX), MDSC could not be reduced, and the growth rate of tumors was accelerated. Consistent with the changes in MDSC, the serum levels of IL-6 and IL-1ß were lowest in the APS group. Meanwhile, we found that fecal suspension from mice in the APS group could also reduce the number of MDSC in tumor tissues. These results revealed that APS regulated the immune function in tumor-bearing mice through remodeling the gut microbiota. Next, we focused on the results of 16S rRNA, which showed that APS significantly regulated most microorganisms, such as Bifidobacterium pseudolongum, Lactobacillus johnsonii and Lactobacillus. According to the Spearman analysis, the changes in abundance of these microorganisms were related to the increase of metabolites like glutamate and creatine, which could control tumor growth. The present study demonstrates that APS attenuate the immunosuppressive activity of MDSC in melanoma-bearing mice by remodeling the gut microbiota and fecal metabolites. Our findings reveal the therapeutic potential of APS to control tumor growth.

Dietary supplementation of alpha-lipoic acid mitigates the negative effects of heat stress in broilers.

Heat stress accounts for substantial economic loss in the poultry industry by altering the health and performance of chickens. Alpha-lipoic acid (ALA) is a water and fat-soluble antioxidant which is readily absorbed from the intestine resulting in maximum bioavailability. Moreover, ALA acts as a coenzyme in glucose metabolism and helps generate other antioxidants. Considering these benefits, we hypothesized that dietary supplementation of ALA would help mitigate heat stress in poultry. A total of 72 Day-old broiler chicks were randomly assigned into three treatment groups: no heat stress (NHS), heat stress with basal diet (HS), and heat stress with alpha-lipoic acid (HS+ALA); each treatment group had 6 replicate pens with 4 birds in each pen (n = 24/group). The allocated birds were raised under standard husbandry practices for 3 weeks. After 21 d, birds in the HS and HS+ALA groups were exposed to heat stress (33°C for 8 hours during the day) for 3 weeks, while the NHS group was reared under normal conditions (22-24°C). The HS+ALA group received a basal finisher diet fortified with ALA (500 mg/kg) during the treatment period (22 to 42 d), while other birds were provided with the basal finisher diet. Weekly body weight and feed intake were recorded. The cecum digesta for volatile fatty acids (VFAs) analysis and 16S rRNA sequencing for the gut microbiota analysis; and the ileum tissue samples for histological and gene expression analyses were collected on d 42. Exposure to heat stress decreased (P<0.05) average daily gain (ADG) and final body weight (FBW) in the HS group compared to the NHS group, the supplementation of ALA improved (P<0.05) ADG and FBW in heat-stressed birds. Furthermore, birds in the HS+ALA group had increased (P<0.05) expression of HSP90, PRDX1, GPX3, SOD2, OCLN, and MUC2 genes and higher (P<0.05) concentrations of major VFAs (acetate, propionate, and butyrate). The dietary ALA supplementation also improved the villus height and villus height to crypt depth ratio in the HS+ALA group. The microbial diversity analysis revealed significant abundance (P<0.05) of beneficial bacteria Lactobacillus and Peptostreptococcaceae in the cecum of the ALA group. These results indicate that dietary ALA supplementation effectively mitigates the negative effects of heat stress in broilers by improving the expression of heat-shock, tight-junction, antioxidants, and immune-related genes in the intestine, improving villus structures, increasing concentration of major VFAs, and enriching the beneficial microbiota.