The metabolites of lactic acid bacteria: classification, biosynthesis and modulation of gut microbiota

Sargassum horneri extract fermented by Lactiplantibacillus pentosus SH803 mediates adipocyte metabolism in 3T3-L1 preadipocytes by regulating oxidative damage and inflammation

Sargassum horneri (S. horneri), a brown seaweed excessively proliferating along Asian coastlines, are damaging marine ecosystems. Thus, this study aimed to enhance nutritional value of S. horneri through lactic acid bacteria fermentation to increase S. horneri utilization as a functional food supplement, and consequently resolve coastal S. horneri accumulation. S. horneri supplemented fermentation was most effective with Lactiplantibacillus pentosus SH803, thus this product (F-SHWE) was used for further in vitro studies. F-SHWE normalized expressions of oxidative stress related genes NF-κB, p53, BAX, cytochrome C, caspase 9, and caspase 3, while non-fermented S. horneri (SHWE) did not, in a H2O2-induced HT-29 cell model. Moreover, in an LPS-induced HT-29 cell model, F-SHWE repaired expressions of inflammation marker genes ZO1, IL1β, IFNγ more effectively than SHWE. For further functional assessment, F-SHWE was also treated in 3T3-L1 adipocytes. As a result, F-SHWE decreased lipid accumulation, along with gene expression of adipogenesis markers PPARγ, C/EBPα, C/EBPβ, aP2, and Lpl; lipogenesis markers Lep, Akt, SREBP1, Acc, Fas; inflammation markers IFN-γ and NF-κB. Notably, gene expression of C/EBPβ, IFN-γ and NF-κB were suppressed only by F-SHWE, suggesting the enhancing effect of fermentation on obesity-related properties. Compositional analysis attributed the protective effects of F-SHWE to acetate, an organic acid significantly higher in F-SHWE than SHWE. Therefore, F-SHWE is a novel potential anti-obesity agent, providing a strategy to reduce excess S. horneri populations along marine ecosystems.

Harnessing the Health and Techno-Functional Potential of Lactic Acid Bacteria: A Comprehensive Review

This review examines the techno-functional properties of lactic acid bacteria (LABs) in the food industry, focusing on their potential health benefits. We discuss current findings related to the techno-functionality of LAB, which includes acidification, proteolytic and lipolytic features, and a variety of other biochemical activities. These activities include the production of antimicrobial compounds and the synthesis of exopolysaccharides that improve food safety and consumer sensory experience. LABs are also known for their antioxidant abilities, which help reduce oxidative reactions in foods and improve their functional properties. In addition, LABs' role as probiotics is known for their promising effects on gut health, immune system modulation, cholesterol control, and general wellbeing. Despite these advantages, several challenges hinder the effective production and use of probiotic LABs, such as maintaining strain viability during storage and transport as well as ensuring their efficacy in the gastrointestinal tract. Our review identifies these critical barriers and suggests avenues for future research.

Identification of novel probiotic lactic acid bacteria from soymilk waste using the 16s rRNA gene for potential use in poultry

Background and Aim

In-feed antibiotics have been used as antibiotic growth promoters (AGPs) to enhance the genetic potential of poultry. However, the long-term use of AGPs is known to lead to bacterial resistance and antibiotic residues in poultry meat and eggs. To address these concerns, alternatives to AGPs are needed, one of which is probiotics, which can promote the health of livestock without having any negative effects. In vitro probiotic screening was performed to determine the ability of lactic acid bacteria (LAB) isolated from soymilk waste to be used as a probiotic for livestock.

Materials and Methods

Four LAB isolates (designated F4, F6, F9, and F11) isolated from soymilk waste were used in this study. In vitro testing was performed on LAB isolates to determine their resistance to temperatures of 42°C, acidic pH, bile salts, hydrophobicity to the intestine, and ability to inhibit pathogenic bacteria. A promising isolate was identified using the 16S rRNA gene.

Result

All LAB isolates used in this study have the potential to be used as probiotics. On the basis of the results of in vitro testing, all isolates showed resistance to temperatures of 42°C and low pH (2.5) for 3 h (79.87%-94.44%) and 6 h (76.29%-83.39%), respectively. The survival rate at a bile salt concentration of 0.3% ranged from 73.24% to 90.39%, whereas the survival rate at a bile salt concentration of 0.5% ranged from 56.28% to 81.96%. All isolates showed the ability to attach and colonize the digestive tract with a hydrophobicity of 87.58%-91.88%. Inhibitory zones of LAB against pathogens ranged from 4.80-15.15 mm against Staphylococcus aureus, 8.85-14.50 mm against Salmonella enteritidis, and 6.75-22.25 mm against Escherichia coli. Although all isolates showed good ability as probiotics, isolate F4 showed the best probiotic ability. This isolate was identified as Lactobacillus casei strain T22 (JQ412731.1) using the 16S rRNA gene.

Conclusion

All isolates in this study have the potential to be used as probiotics. However, isolate F4 has the best probiotic properties and is considered to be the most promising novel probiotic for poultry.

Cell-free supernatants from Lactobacillus strains exert antibacterial, antibiofilm, and antivirulence activity against Pseudomonas aeruginosa from cystic fibrosis patients

Chronic lung infections caused by Pseudomonas aeruginosa play a significant role in the mortality and morbidity of cystic fibrosis (CF) patients. The widespread bacterial resistance to conventional antimicrobials demands identifying new strategies to complement or replace current antibiotic therapies. In this study, we evaluated the antibacterial, antibiofilm, and antivirulence properties of cell-free supernatants (CFS) from several Lactobacillus probiotic strains against P. aeruginosa isolated from the sputum of CF patients. A strong and fast antibacterial activity of CFS from different strains of lactobacilli was observed at acidic pH towards P. aeruginosa, both in planktonic and biofilm mode of growth, in conditions mimicking CF lung. Interestingly, although when adjusted at pH 6.0, CFS lost most of their antibacterial potential, they retained some antivirulence activity towards P. aeruginosa, largely dependent on the dose, exposure time, and the Lactobacillus-P. aeruginosa strain combination. In vivo testing in the invertebrate Galleria mellonella model disclosed the lack of toxicity of acidic CFS and their ability to prevent P. aeruginosa infection. For the first time, the results revealed lactobacilli postbiotic activities in the context of the pulmonary environment, pointing to innovative postbiotics' uses in anti-infective therapy.

Isolation and Identification of Chicken-Derived Lactic Acid Bacteria: In Vitro Probiotic Properties and Antagonistic Effects against Salmonella pullorum, Staphylococcus aureus, and Escherichia coli

The development of probiotics capable of quickly colonizing the intestines of animals is important in promoting the healthy growth of livestock. The aim of this study was to screen lactic acid bacteria (LAB) from the intestinal microbiota of chickens with potential applications, and to evaluate their probiotic properties and antagonistic abilities against Salmonella pullorum, Staphylococcus aureus, and Escherichia coli. The results showed that a total of 79 strains with the characteristics of LAB were isolated from the chicken cecum microbiota, of which 7 strains exhibited strong inhibitory activity against S. pullorum, S. aureus, and E. coli. Performing 16s rDNA sequencing revealed that these seven strains were Lactiplantibacillus pentosus (n = 1), Lactiplantibacillus plantarum (n = 3), Lactiplantibacillus paraplantarum (n = 1), Lactiplantibacillus argentoratensis (n = 1), and Lactiplantibacillus fabifermentans (n = 1). Among them, L. pentosus R26 and L. plantarum R32 exhibited superior antibacterial activity. These two strains demonstrated high lactic acid production ability, with survival rates of 86.29% and 87.99% after 3 h of treatment at pH 1.5, 86.66% and 85.52% after 3 h of treatment with 0.5% bile salts, 90.03% and 88.16% after 2 h of treatment with simulated gastric fluid, and 98.92% and 98.22% after 2 h of treatment with simulated intestinal fluid, respectively. Co-cultivation with L. pentosus R26 for 24 h resulted in 50% of the pathogens being antagonized, while almost complete inhibition was observed following 72 h of co-cultivation. In conclusion, L. pentosus R26 and L. plantarum R32 exhibited high antibacterial activity and acid production capability, while also demonstrating satisfactory tolerance to low pH values and high concentrations of bile salts and digestive fluid. The probiotic characteristics and stress resistance of L. pentosus R26 were slightly superior to those of L. plantarum R32, indicating its potential for development as a probiotic.

Review of yeast culture concerning the interactions between gut microbiota and young ruminant animals

Microorganisms inhabit the gastrointestinal tract of ruminants and regulate body metabolism by maintaining intestinal health. The state of gastrointestinal health is influenced not only by the macro-level factors of optimal development and the physiological structure integrity but also by the delicate equilibrium between the intestinal flora and immune status at the micro-level. Abrupt weaning in young ruminants causes incomplete development of the intestinal tract resulting in an unstable and unformed microbiota. Abrupt weaning also induced damages to the microecological homeostasis of the intestinal tract, resulting in the intestinal infections and diseases, such as diarrhea. Recently, nutritional and functional yeast culture has been researched to tackle these problems. Herein, we summarized current known interactions between intestinal microorganisms and the body of young ruminants, then we discussed the regulatory effects of using yeast culture as a feed supplement. Yeast culture is a microecological preparation that contains yeast, enriched with yeast metabolites and other nutrient-active components, including β-glucan, mannan, digestive enzymes, amino acids, minerals, vitamins, and some other unknown growth factors. It stimulates the proliferation of intestinal mucosal epithelial cells and the reproduction of intestinal microorganisms by providing special nutrient substrates to support the intestinal function. Additionally, the β-glucan and mannan effectively stimulate intestinal mucosal immunity, promote immune response, activate macrophages, and increase acid phosphatase levels, thereby improving the body's resistance to several disease. The incorporation of yeast culture into young ruminants' diet significantly alleviated the damage caused by weaning stress to the gastrointestinal tract which also acts an effective strategy to promote the balance of intestinal flora, development of intestinal tissue, and establishment of mucosal immune system. Our review provides a theoretical basis for the application of yeast culture in the diet of young ruminants.

Unraveling the antimicrobial potential of Lactiplantibacillus plantarum strains TE0907 and TE1809 sourced from Bufo gargarizans: advancing the frontier of probiotic-based therapeutics

Introduction

In an era increasingly defined by the challenge of antibiotic resistance, this study offers groundbreaking insights into the antibacterial properties of two distinct Lactiplantibacillus plantarum strains, TE0907 and TE1809, hailing from the unique ecosystem of Bufo gargarizans. It uniquely focuses on elucidating the intricate components and mechanisms that empower these strains with their notable antibacterial capabilities.

Methods

The research employs a multi-omics approach, including agar diffusion tests to assess antibacterial efficacy and adhesion assays with HT-29 cells to understand the preliminary mechanisms. Additionally, gas chromatography-mass spectrometry (GC-MS) is employed to analyze the production of organic acids, notably acetic acid, and whole-genome sequencing is utilized to identify genes linked to the biosynthesis of antibiotics and bacteriocin-coding domains.

Results

The comparative analysis highlighted the exceptional antibacterial efficacy of strains TE0907 and TE1809, with mean inhibitory zones measured at 14.97 and 15.98 mm, respectively. A pivotal discovery was the significant synthesis of acetic acid in both strains, demonstrated by a robust correlation coefficient (cor ≥ 0.943), linking its abundance to their antimicrobial efficiency. Genomic exploration uncovered a diverse range of elements involved in the biosynthesis of antibiotics similar to tetracycline and vancomycin and potential regions encoding bacteriocins, including Enterolysin and Plantaricin.

Conclusion

This research illuminates the remarkable antibacterial efficacy and mechanisms intrinsic to L. plantarum strains TE0907 and TE1809, sourced from B. gargarizans. The findings underscore the strains' extensive biochemical and enzymatic armamentarium, offering valuable insights into their role in antagonizing enteric pathogens. These results lay down a comprehensive analytical foundation for the potential clinical deployment of these strains in safeguarding animal gut health, thereby enriching our understanding of the role of probiotic bacteria in the realm of antimicrobial interventions.

Anti-Obesity Effect of Kimchi with Starter Cultures in 3T3-L1 Cells

Lactic acid bacteria (LAB) isolated from kimchi have various functions, including antioxidant, anti-inflammation, and anti-obesity activities, and are therefore widely used in the food, pharmaceutical, and medical fields. To date, the health functionalities of LAB have been widely reported; however, those of kimchi fermented with LAB as a starter have rarely been reported. Therefore, research on the selection of LAB with anti-obesity activity and the health functionality of kimchi fermented with LAB is needed. In the present study, LAB with anti-obesity activity were initially selected by measuring the Oil-Red O intensity. Among the four LAB strains, anti-obesity activity was confirmed by measuring cell viability, lipid levels, and lipid accumulation. Then, starter kimchi (SK) was prepared by inoculating selected LABs, and its pH, total acidity, and salinity were compared with those of naturally fermented kimchi (NK). Lastly, anti-obesity activity was also investigated in 3T3-L1 cells. Selected LAB showed no cytotoxicity up to 107 CFU/ml, with Lactobacillus brevis JC7 and Leuconostoc mesenteroides KCKM0828 having higher inhibitory effects on TG, TC content and lipid accumulation. Most SKs showed fermentation properties similar to those of the NK. SKs showed no cytotoxicity at concentrations of up to 1,000 μg/ml. SKs showed strong inhibitory effects on TG content, lipid accumulation, and obesity-related gene and protein expressions. Taken together, the utilization of LAB as a starter could improve the health benefits of kimchi.

Lactate exacerbates lung damage induced by nanomicroplastic through the gut microbiota-HIF1a/PTBP1 pathway

Exposure to nanomicroplastics (nano-MPs) can induce lung damage. The gut microbiota is a critical modulator of the gut-lung axis. However, the mechanisms underlying these interactions have not been elucidated. This study explored the role of lactate, a key metabolite of the microbiota, in the development of lung damage induced by nano-MPs (LDMP). After 28 days of exposure to nano-MPs (50-100 nm), mice mainly exhibited damage to the lungs and intestinal mucosa and dysbiosis of the gut microbiota. Lactate accumulation was observed in the lungs, intestines and serum and was strongly associated with the imbalance in lactic acid bacteria in the gut. Furthermore, no lactate accumulation was observed in germ-free mice, while the depletion of the gut microbiota using a cocktail of antibiotics produced similar results, suggesting that lactate accumulation in the lungs may have been due to changes in the gut microbiota components. Mechanistically, elevated lactate triggers activation of the HIF1a/PTBP1 pathway, exacerbating nano-MP-induced lung damage through modulation of the epithelial-mesenchymal transition (EMT). Conversely, mice with conditional knockout of Ptbp1 in the lungs (Ptbp1flfl) and PTBP1-knockout (PTBP1-KO) human bronchial epithelial (HBE) cells showed reversal of the effects of lactate through modulation of the HIF1a/PTBP1 signaling pathway. These findings indicate that lactate is a potential target for preventing and treating LDMP.

Using metabolomics to understand stress responses in Lactic Acid Bacteria and their applications in the food industry

BACKGROUND

Lactic Acid Bacteria (LAB) are commonly used as starter cultures, probiotics, to produce lactic acid and other useful compounds, and even as natural preservatives. For use in any food product however, LAB need to survive the various stresses they encounter in the environment and during processing. Understanding these mechanisms may enable direction of LAB biochemistry with potential beneficial impact for the food industry.

AIM OF REVIEW

To give an overview of the use of LAB in the food industry and then generate a deeper biochemical understanding of LAB stress response mechanisms via metabolomics, and methods of screening for robust strains of LAB.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Uses of LAB in food products were assessed and factors which contribute to survival and tolerance in LAB investigated. Changes in the metabolic profiles of LAB exposed to stress were found to be associated with carbohydrates, amino acids and fatty acid levels and these changes were proposed to be a result of the bacteria trying to maintain cellular homeostasis in response to external conditions and minimise cellular damage from reactive oxygen species. This correlates with morphological analysis which shows that LAB can undergo cell elongation and shortening, as well as thinning and thickening of cell membranes, when exposed to stress. It is proposed that these innate strategies can be utilised to minimise negative effects caused by stress through selection of intrinsically robust strains, genetic modification and/or prior exposure to sublethal stress. This work demonstrates the utility of metabolomics to the food industry.

Bacterium-like particles derived from probiotics: progress, challenges and prospects

Bacterium-like particles (BLPs) are hollow peptidoglycan particles obtained from food-grade Lactococcus lactis inactivated by hot acid. With the advantage of easy preparation, high safety, great stability, high loading capacity, and high mucosal delivery efficiency, BLPs can load and display proteins on the surface with the help of protein anchor (PA), making BLPs a proper delivery system. Owning to these features, BLPs are widely used in the development of adjuvants, vaccine carriers, virus/antigens purification, and enzyme immobilization. This review has attempted to gather a full understanding of the technical composition, characteristics, applications. The mechanism by which BLPs induces superior adaptive immune responses is also discussed. Besides, this review tracked the latest developments in the field of BLPs, including Lactobacillus-derived BLPs and novel anchors. Finally, the main limitations and proposed breakthrough points to further enhance the immunogenicity of BLPs vaccines were discussed, providing directions for future research. We hope that further developments in the field of antigen delivery of subunit vaccines or others will benefit from BLPs.

Latilactobacillus curvatus FFZZH5L isolated from pickled cowpea enhanced antioxidant activity in Caenorhabditis elegans by upregulating the level of glutathione S-transferase

Latilactobacillus curvatus is a potential probiotic that possesses beneficial health properties and fermentation traits; however, the extent of understanding of the antioxidant activities of L. curvatus is limited. This study investigates the antioxidant activities of a new L. curvatus FFZZH5L strain. The strain exhibits broad tolerance to acids, bases and salts and demonstrated good adaption to the gastrointestinal environment, with a survival rate of 45% after 24 h of treatment in artificial gastrointestinal juice. Moreover, L. curvatus FFZZH5L exhibits inhibitory effects on Staphylococcus aureus, with a self-aggregation rate of 34.8% and a co-aggregation rate of 82.2%. In vitro, the DPPH radical scavenging ability and GSH-px enzyme activity of L. curvatus FFZZH5L reach 64.27% and 15.95 U mL-1, respectively. Treatment of C. elegans with L. curvatus FFZZH5L in vivo significantly extended the organism's lifespan. Furthermore, the activity of SOD, GSH-px and T-AOC was increased by 33.6%, 43.4% and 58.3%, respectively. Feeding C. elegans with L. curvatus FFZZH5L decreased the MDA, lipofuscin and ROS levels by 9%-36.4%. L. curvatus FFZZH5L effectively protected C. elegans against juglone-induced oxidative stress damage and led to a significant increase in the organism's survival under heat stress. The RT-qPCR analysis suggests that feeding C. elegans with L. curvatus FFZZH5L upregulates the expression levels of antioxidant-related genes including glutathione S-transferase 4 (gst-4), gst-1, gst-10, sod-3, sod-5, and sod-10 in C. elegans. Our investigation confirms the probiotic and antioxidant properties of L. curvatus, indicating its potential application in functional foods and the pharmaceutical industry.

Probiotic-Derived Bioactive Compounds in Colorectal Cancer Treatment

Colorectal cancer (CRC) is a multifactorial disease with increased morbidity and mortality rates globally. Despite advanced chemotherapeutic approaches for the treatment of CRC, low survival rates due to the regular occurrence of drug resistance and deleterious side effects render the need for alternative anticancer agents imperative. Accumulating evidence supports that gut microbiota imbalance precedes the establishment of carcinogenesis, subsequently contributing to cancer progression and response to anticancer therapy. Manipulation of the gut microbiota composition via the administration of probiotic-derived bioactive compounds has gradually attained the interest of scientific communities as a novel therapeutic strategy for CRC. These compounds encompass miscellaneous metabolic secreted products of probiotics, including bacteriocins, short-chain fatty acids (SCFAs), lactate, exopolysaccharides (EPSs), biosurfactants, and bacterial peptides, with profound anti-inflammatory and antiproliferative properties. This review provides a classification of postbiotic types and a comprehensive summary of the current state of research on their biological role against CRC. It also describes how their intricate interaction with the gut microbiota regulates the proper function of the intestinal barrier, thus eliminating gut dysbiosis and CRC development. Finally, it discusses the future perspectives in precision-medicine approaches as well as the challenges of their synthesis and optimization of administration in clinical studies.