Characterization of Cetobacterium somerae CPU-CS01 isolated from the intestine of healthy crucian carp (Carassius auratus) as potential probiotics against Aeromonas hydrophila infection.

Cetobacterium somerae is a commensal bacterium for many fish species. However, research on C. somerae has been limited so far, and its function and beneficial potential require to be further investigated. The objective of this study was to evaluate the probiotic properties of C. somerae CPU-CS01 isolated from the intestinal contents of crucian carp (Carassius auratus). Hemolytic activity, antibiotic susceptibility, acid tolerance, bile salt tolerance, free radical scavenging, and enzyme production properties were tested for in vitro. Caenorhabditis elegans and zebrafish (Danio rerio) model were used to evaluate the antioxidant and anti-infective effects of C. somerae CPU-CS01 in vivo. Our results showed that C. somerae CPU-CS01 had no hemolytic activity, it produced cellulase, amylase, and survived at low pH (2.0-3.0) and in the presence of bile salts. The cell-free culture supernatant (CFCS) of C. somerae CPU-CS01 possessed DPPH radical, hydroxyl radical, and superoxide anion scavenging activity. C. elegans fed with C. somerae CPU-CS01 were more resistant to hydrogen peroxide-induced oxidative stress and Aeromonas hydrophila infection. In addition, zebrafish-fed diets containing C. somerae CPU-CS01 showed improved survival after A. hydrophila infection. Based on these results, the positive probiotic properties of C. somerae CPU-CS01 isolated from the intestinal contents of crucian carp make it a potential candidate for probiotic.

SCFAs improve disease resistance via modulate gut microbiota, enhance immune response and increase antioxidative capacity in the host.

To evaluate the effects of dietary short chain fatty acids (SCFAs) on the intestinal health and innate immunity in crucian carp, a six-week feeding trial was carried out with following treatments: basal diet (BD), basal diet supplementation with 1% sodium acetate (BDSA), basal diet supplementation with 1% sodium propionate (BDSP) and basal diet supplementation with 1% sodium butyrate (BDSB). The results showed dietary BDSA, BDSP and BDSB could protect the host against oxidative stress by improving the activity of certain antioxidative enzymes (T-SOD, GSH-Px and CAT). Additionally, dietary SCFAs could enhance mucosal and humoral immune responses by improving certain innate immune parameters in serum and skin mucus productions (IgM, ACH50 and T-SOD). Furthermore, dietary BDSA and BDSP could up-regulate the expression of immune related genes (TNF-α, TGF-ß and IL-8) and tight junction protein genes (occludin and ZO-1). Dietary BDSB could also elevate the expression of IL-8, TGF-ß, ZO-1 and Occludin in the midgut. Although dietary differences of SCFAs didn't alter the α-diversity of the intestinal flora, they altered the core microbiota. Finally, the challenge trial showed that dietary basal diet supplementation with SCFAs could protect zebrafish against Aeromonas hydrophila. These results suggest that dietary SCFAs could improve innate immunity, modulate gut microbiota and increase disease resistance in the host, which indicated the potential of SCFAs as immunostimulants in aquaculture.

Exploring of probiotic potential vaginal lactobacillus isolates from healthy women against Gardnerella vaginalis and Caenorhabditis elegans model testing.

AIM: Lactobacillus species are the dominant microorganisms in the vaginal microbiota of healthy women and play an important role in the defence against pathogens. This study aimed to evaluate probiotic potential of Lactiplantibacillus plantarum strain P1 isolated from healthy woman's vaginal discharge for its further utilization as a promising candidate strain in the treatment of bacterial vaginosis caused by Gardnerella vaginalis. METHODS AND RESULTS: Ten lactobacilli strains from a woman's vaginal discharge were evaluated for their probiotic potential, including growth capacity at different pH levels (pH 3.5-4.5), acid production, hydrogen peroxide production capacity, antibacterial activity and susceptibility to antibiotics. Moreover, in vitro safety assay haemolytic activity and mutagenicity were investigated for safety assessment. In vivo Caenorhabditis elegans infection model was used to investigate the anti-infection effect of selected isolates. We found that lactobacilli strain P1 showed strong growth ability in low acid environment, produced acid, hydrogen peroxide, had the strongest antibacterial activity against G. vaginalis and was highly susceptible to the tested antibiotics. When assayed for the safety, strain P1 showed no haemolytic activity and had no effect of mutagenicity. Moreover, P1 significantly increased the lifespan of C. elegans against G. vaginalis infection. Combined with the results of 16S rRNA gene sequencing, morphological and physiological characteristic, the strain was identified as Lactiplantibacillus plantarum. CONCLUSION: Lactiplantibacillus plantarum strain P1 proves to be a promising candidate strain in the treatment of bacterial vaginosis caused by G. vaginalis. SIGNIFICANCE AND IMPACT OF THE STUDY: Conventional antibiotic therapy for bacterial vaginosis has led to the accelerated process of bacterial drug resistance. Probiotics are potentially an alternative method for bacterial vaginosis therapy. This finding provides bacterial resources for keeping pathogens away from the vagina. We believe L. plantarum P1 may be used as vaginal probiotics and be useful to prevent or treat bacterial vaginitis.

Pseudomonas putida HE alleviates glyphosate-induced toxicity in earthworm: Insights from the neurological, reproductive and immunological status.

The proceeding study aimed to isolate glyphosate-degrading bacteria from soil and determine optimal degradation conditions through single-factor experiments and response surface methodology. The detoxifying efficacy of the isolate on glyphosate was assessed using earthworm model. The results indicate that Pseudomonas putida HE exhibited the highest glyphosate degradation rate. Optimal conditions for glyphosate degradation were observed at an inoculation percentage of approximately 5%, a pH of 7, and a temperature of 30 °C. Glyphosate induced notable neurotoxicity and reproductive toxicity in earthworms, evidenced by reduced activity of the neurotoxicity-associated enzyme AChE. Additionally, an increase in the activities of catalase, superoxide dismutase, and lactate dehydrogenase was observed. H&E staining revealed structural disruptions in the earthworm clitellum, with notable atrophy in the structure of spermathecae. Furthermore, glyphosate activation of earthworm immune systems led to increased expression of immune-related genes, specifically coelomic cytolytic factor and lysozyme. Notably, the introduction of strain HE mitigated the glyphosate toxicity to the earthworms mentioned above. P. putida HE was able to increase soil enzyme activities that were reduced due to glyphosate. The isolate P. putida HE, emerged as an effective and cost-efficient remedy for glyphosate degradation and toxicity reduction in natural settings, showcasing potential applications in real ecological settings.

Saccharomyces cerevisiae SC-2201 Attenuates AOM/DSS-Induced Colorectal Cancer by Modulating the Gut Microbiome and Blocking Proinflammatory Mediators.

Colorectal cancer is the third most common cancer in the world today, and studies have shown that the ratio of Candida to Saccharomyces cerevisiae increased, and the abundance of S. cerevisiae in the intestines of patients with colorectal cancer decreased, which suggests that there is an imbalance in the proportion of fungi in the intestines of patients with colorectal cancer. The objective of this study was to screen S. cerevisiae isolate from traditional Chinese fermentation starters and assess its ability to ameliorate dysbiosis and to alleviate the carcinogenic process of azoxymethane/dextran sodium sulfate-induced colorectal cancer in mice model. S. cerevisiae strain SC-2201 was isolated and exhibited probiotic properties, including the ability to survive in an acidic pH environment and in the presence of bile salts in the gastrointestinal tract, as well as antioxidant activities. Oral administration of S. cerevisiae SC-2201 not only alleviated weight loss but also reduced colonic shortening and histological damage in azoxymethane/dextran sodium sulfate-induced colorectal cancer in mice. Furthermore, the administration of S. cerevisiae SC-2201 suppressed the expression of proinflammatory mediators, such as interleukin-1ß, interleukin-6, cyclooxygenase-2, vascular endothelial growth factor, nucleotide-binding domain, leucine-rich repeat, and pyrin domain-containing protein 3. Specifically, the analysis of gut bacteriome showed a significant decrease in Bacteroidota and Campylobacterota levels, as well as an increase in Proteobacteria level in the colorectal cancer group, which was alleviated by supplementation with S. cerevisiae SC-2201. The analysis of the mycobiome revealed a significant increase in the levels of Basidiomycota, Apiosordaria, Naganishia, and Taphrina genera in the colorectal cancer group, which were alleviated after supplementation with S. cerevisiae SC-2201. However, the levels of Xenoramularia, Entoloma, and Keissleriella were significantly increased after administration with S. cerevisiae SC-2201. Overall, the findings of this study demonstrate that S. cerevisiae SC-2201 possesses potential probiotic properties and can effectively attenuate the development of colorectal cancer, highlighting its cancer-preventive potential. This is the first report of a S. cerevisiae strain isolated from traditional Chinese fermentation starters which showed good probiotic properties, and mitigated azoxymethane/dextran sodium sulfate-induced colorectal cancer by modulating the gut microbiome and blocking proinflammatory mediators in mice.

Synthetic microbial consortia for the treatment of Clostridioides difficile infection in mice model.

Clostridioides difficile infection (CDI) as of recent has become a great concern to the impact on human health due to its high hazardous risk and rate of recurrence. Live bacterial therapeutics is a promising method to treat or prevent CDI. Here, a synthetic microbial consortia (SMC) B10 was constructed using probiotic strains with antibacterial and anti-quorum sensing activities, and the therapeutic effect of SMC B10 against C. difficile infection was evaluated in vitro. Compared to the model group, the treatment of SMC B10 significantly increased the survival rate. The clinical signs of mice were significantly ameliorated, especially the cecum injury, while the secretion of pro-inflammatory associated cytokines such as IL-1α, IL-6, IL-17A and TNF-α was reduced, the expression of TLR4 was inhibited, which alleviated the inflammatory response, and the expression of the tight junction protein Claudin-1 was increased, ultimately promoting the recovery of host health. The treatment of B10 restored gut microbiota dysbiosis and led to a healthy intestinal microbiota structure, significantly improved alpha diversity, suppressing potentially harmful bacteria and restoring other core bacterial species. In conclusion, SMC B10 can effectively treat CDI through modulate gut microbiota and attenuate the inflammatory response.

Synthetic bacterial consortia transplantation for the treatment of Gardnerella vaginalis-induced bacterial vaginosis in mice.

Bacterial vaginosis (BV) is a disease caused by vaginal microbiota dysbiosis. Here, we propose the use of synthetic bacterial consortia transplantation (SBCT) for the treatment of Gardnerella vaginalis-induced BV mice. The results showed that SBCT significantly reduced vaginal tissue damage and restored the vaginal microbiota, decreased the secretion of pro-inflammatory cytokines (IL-1ß and IL-8), and suppressed NF-κB activation. IL-17, iNOS, and COX-2 expression in vaginal tissue were also down-regulated. However, IL-10 and Foxp3 showed up-regulated expression in mice. Compared with vaginal microbiota transplantation (VMT), results indicated that VMT was more effective than SBCT in suppressing G. vaginalis-induced inflammation. The obtained results suggest that synthetic bacterial consortia might be used as a potential biotherapeutic agent for the treatment of G. vaginalis-induced bacterial vaginosis. Video Abstract.

Acetobacter pasteurianus BP2201 alleviates alcohol-induced hepatic and neuro-toxicity and modulate gut microbiota in mice.

The excessive consumption of alcohol results in a dysbiosis of the gut microbiota, which subsequently impairs the gut microbiota-brain/liver axes and induces cognitive dysfunction and hepatic injury. This study aimed to investigate the potential effect of Acetobacter pasteurianus BP2201 in reducing the negative effects of alcohol consumption on cognitive function and liver health by modulating the gut microbiota-brain/liver axes. Treatment with A. pasteurianus BP2201 improved alcohol-induced hippocampal damage, suppressed neuroinflammation, promoted neuroprotein expression in the hippocampus and enhanced cognitive function. At the same time, A. pasteurianus BP2201 can also reduce serum lipid levels, relieve oxidative stress, inhibit TLR4/MyD88/NF-κB pathway, reduce the secretion of TNF-α and IL-1ß, so as to improve alcoholic liver injury. Concomitantly, the treatment with A. pasteurianus BP2201 leads to a shift in the intestinal microbiota structure towards that of healthy individuals, inhibiting the proliferation of harmful bacteria and promoting the recovery of beneficial bacteria. In addition, it also improves brain cognitive dysfunction and liver health by affecting the gut microbiota-brain/liver axes by promoting the synthesis of relevant amino acids and the metabolism of nucleotide base components. These findings demonstrate the potential of regulating the gut microbiome and gut microbiota-brain/liver axes to mitigate alcohol-induced disease.

Fusobacterium nucleatum and its metabolite hydrogen sulfide alter gut microbiota composition and autophagy process and promote colorectal cancer progression.

IMPORTANCE: Colorectal cancer (CRC) is the second most common cancer in the world; the main treatment for CRC is immunosuppressive therapy, but this therapy is only effective for a small percentage of CRC patients, so there is an urgent need for a treatment with fewer side effects and higher efficacy. This study demonstrated that Fusobacterium nucleatum with increased abundance in CRC can regulate the autophagy process and disrupt normal intestinal microbiota by producing hydrogen sulfide, factors that may be involved in the development and progression of CRC. This study may provide a reference for future CRC treatment options that are efficient and have fewer side effects.