Complete genome sequence of bacteriocin-producing Lactobacillus plantarum KLDS1.0391, a probiotic strain with gastrointestinal tract resistance and adhesion to the intestinal epithelial cells

Probiotic Characteristics and Whole Genome Analysis of Lactiplantibacillus plantarum PM8 from Giant Panda (Ailuropoda melanoleuca) Milk

Milk is a rich source of probiotics, particularly lactic acid bacteria (LAB), which have been shown to promote gut health, support the immune system, enhance digestion, and prevent pathogen colonization. This study aimed to isolate and identify LAB strains from giant panda (Ailuropoda melanoleuca) milk, evaluate their probiotic properties, and analyze the genomic characteristics of a promising strain. Thirteen LAB strains were isolated from 12 samples of giant panda milk. Among all LAB strains, Lactiplantibacillus plantarum PM8 (PM8) demonstrated probiotic properties and safety features. It exhibited strong growth performance, high antipathogenic activity against four pathogens, and strong survival rates under simulated gastrointestinal conditions. PM8 also showed excellent adhesion capabilities to Caco-2 cells. Additionally, safety assessment revealed no hemolysin production and minimal antibiotic resistance, making it a promising candidate for probiotic applications. The genome of PM8 consists of 3,227,035 bp with a GC content of 44.60% and contains 3171 coding sequences, including 113 carbohydrate-active enzyme genes and genes related to exopolysaccharides synthesis, vitamin B biosynthesis, adhesion, antioxidant activity, and bile salt hydrolysis. Notably, it contains genes involved in nonribosomally synthesized secondary metabolite and bacteriocin production. The genomic safety analysis confirmed that PM8 lacks the capacity to transmit bacterial antimicrobial resistance and is non-pathogenic to both humans and animals. These findings suggest that PM8 holds considerable potential for enhancing gut health and supporting the development of safe probiotic products.

Metabolic and protein expression responses of Shewanella baltica in golden pomfret broths to slightly acidic electrolysed water

Shewanella baltica is a specific spoilage organism of golden pomfret. This study aims to explore the antibacterial mechanism of slightly acidic electrolysed water (SAEW) against S. baltica (strains ABa4, ABe2 and BBe1) in golden pomfret broths by metabolomics, proteomics and bioinformatics analyses. S. baltica was decreased by at least 3.94 log CFU/mL after SAEW treatment, and strain ABa4 had the highest resistance. Under SAEW stress, amino acids and organic acids in S. baltica decreased, and nucleotide related compounds degraded. Furthermore, 100 differentially expressed proteins (DEPs) were identified. Most DEPs of strains ABe2 and BBe1 were down-regulated, while some DEPs of strain ABa4 were up-regulated, especially those oxidative stress related proteins. These results suggest that the modes of SAEW against S. baltica can be traced to the inhibition of amino acid, carbon, nucleotide and sulphur metabolisms, and the loss of functional proteins for temperature regulation, translation, motility and protein folding.

Protective Potential of Limosilactobacillus fermentum Strains and Their Mixture on Inflammatory Bowel Disease via Regulating Gut Microbiota in Mice

The aim of this study is to investigate the protective potential of Limosilactobacillus fermentum IM57, IR51, and IR62 strains, isolated from infant feces, and their mixture against inflammatory bowel disease (IBD). The strains exhibited robust antioxidant activities and anti-inflammatory properties in RAW 264.7 cells. Subsequently, the potential protective effects of each of these three strains, along with their mixture, were evaluated in a murine colitis model induced by dextran sodium sulfate (DSS). Noteworthy improvements in physiological parameters such as body weight, disease activity index, and colon length were observed in mice treated with the mixture followed by IR62. Additionally, administration of each strain and the mixture mitigated DSS-induced changes in gut microbiota composition with increased abundance of Lactobacillus, Bifidobacterium, Ruminococcus, and Muribaculum, compared to DSS-treated mice. Interestingly, the abundance of Muribaculum increased approximately 2.4-fold after administration of the mixture compared to before administration. Additionally, the concentration of short-chain fatty acids (SCFAs) was significantly reduced in DSS-treated group compared to the control group, while the mixture treatment group had the highest concentration of SCFAs. Furthermore, due to these changes in microbiota and the leading metabolites induced by treatment of the mixture, DSS-induced dysregulation of inflammationand barrier function-related mRNA expressions was significantly inhibited in the group fed with the mixture. Consequently, this study indicates that the multi-strain mixture of L. fermentum strains may play a crucial role in modulating gut microbiota, thereby alleviating IBD through the synergistic effect of the individual effects of the three strains.

Genomic Characterization of Lactiplantibacillus plantarum Strains: Potential Probiotics from Ethiopian Traditional Fermented Cottage Cheese

BACKGROUND

Lactiplantibacillus plantarum is a species found in a wide range of ecological niches, including vegetables and dairy products, and it may occur naturally in the human gastrointestinal tract. The precise mechanisms underlying the beneficial properties of these microbes to their host remain obscure. Although Lactic acid bacteria are generally regarded as safe, there are rare cases of the emergence of infections and antibiotic resistance by certain probiotics.

OBJECTIVE

An in silico whole genome sequence analysis of putative probiotic bacteria was set up to identify strains, predict desirable functional properties, and identify potentially detrimental antibiotic resistance and virulence genes.

METHODS

We characterized the genomes of three L. plantarum strains (54B, 54C, and 55A) isolated from Ethiopian traditional cottage cheese. Whole-genome sequencing was performed using Illumina MiSeq sequencing. The completeness and quality of the genome of L. plantarum strains were assessed through CheckM.

RESULTS

Analyses results showed that L. plantarum 54B and 54C are closely related but different strains. The genomes studied did not harbor resistance and virulence factors. They had five classes of carbohydrate-active enzymes with several important functions. Cyclic lactone autoinducer, terpenes, Type III polyketide synthases, ribosomally synthesized and post-translationally modified peptides-like gene clusters, sactipeptides, and all genes required for riboflavin biosynthesis were identified, evidencing their promising probiotic properties. Six bacteriocin-like structures encoding genes were found in the genome of L. plantarum 55A.

CONCLUSIONS

The lack of resistome and virulome and their previous functional capabilities suggest the potential applicability of these strains in food industries as bio-preservatives and in the prevention and/or treatment of infectious diseases. The results also provide insights into the probiotic potential and safety of these three strains and indicate avenues for further mechanistic studies using these isolates.

An insight into structure-activity relationships in subclass IIb bacteriocins: Plantaricin EvF

This study reports the structure-activity relationships of a unique subclass IIb bacteriocin, plantaricin EvF, which consists of two peptide chains and possesses potent antimicrobial activity. Because the plantaricin Ev peptide chain lacks an α-helix structure, plantaricin EvF is unable to exert its antimicrobial activity through helix-helix interactions like typical subclass IIb bacteriocins. We have shown by various structural evaluation methods that plantaricin Ev can be stabilized by hydrogen bonding at amino acid residues R3, V12, and R13 to the N-terminal region of plantaricin F. This binding gives plantaricin EvF a special spade-shaped structure that exerts antimicrobial activity. In addition, the root-mean-square deviations (RMSDs) of the amino acid residues Y6, F8, and R13 of plantaricin Ev pre- and post-binding were 1.512, 1.723, and 1.369, respectively, indicating that they underwent large structural changes. The alanine scanning experiments demonstrated the important role of the above key amino acids in maintaining the structural integrity of plantaricin EvF. This study not only reveals the unique structural features of plantaricin EvF, but also provides an insight into the structure-activity relationships of subclass IIb bacteriocins.

Comparative Genomics of Limosilactobacillus reuteri YLR001 Reveals Genetic Diversity and Probiotic Properties

To gain deeper insights into the genomic characteristics of Limosilactobacillus reuteri (L. reuteri) YLR001 and uncover its probiotic properties, in the current study, a comprehensive analysis of its whole genome was conducted, explicitly exploring the genetic variations associated with different host organisms. The genome of YLR001 consisted of a circular 2,242,943 bp chromosome with a GC content of 38.84%, along with three circular plasmids (24,864, 38, 926, and 132,625 bp). Among the 2183 protein-coding sequences (CDSs), the specific genes associated with genetic adaptation and stress resistance were identified. We predicted the function of COG protein genes and analyzed the KEGG pathways. Comparative genome analysis revealed that the pan-genome contained 5207 gene families, including 475 core gene families and 941 strain-specific genes. Phylogenetic analysis revealed distinct host specificity among 20 strains of L. reuteri, highlighting substantial genetic diversity across different hosts. This study enhanced our comprehension of the genetic diversity of L. reuteri YLR001, demonstrated its potential probiotic characteristics, and established more solid groundwork for future applications.

The potential of antifungal peptides derived from Lactiplantibacillus plantarum WYH for biocontrol of Aspergillus flavus contamination

Aspergillus flavus is a notorious fungus that contaminates food crops with toxic aflatoxins, posing a serious threat to human health and the agricultural economy. To overcome the inadequacy of traditional control methods and meet consumer preferences for natural-sources additives, there is an urgent demand for novel biocontrol agents that are safe and efficient. This study aims to investigate the antifungal properties of a novel antifungal agent derived from the biologically safe Lactiplantibacillus plantarum WYH. Firstly, antifungal peptides (AFPs) with a molecular weight of less than 3kD, exhibiting remarkable temperature stability and effectively retarding fungal growth in a dose-dependent manner specifically against A. flavus, were concentrated from the fermentation supernatant of L. plantarum WYH and were named as AFPs-WYH. Further analysis demonstrated that AFPs-WYH might exert antifungal effects through the induction of oxidative stress, disruption of mitochondrial function, alteration of membrane permeability, and cell apoptosis in A. flavus. To further validate our findings, a transcriptomics analysis was conducted on A. flavus treated with 2 and 5 mg/mL of AFPs-WYH, which elucidated the potential effect of AFPs-WYH administration on the regulation of genes involved in impairing fungal development and preventing aflatoxin biosynthesis pathways. Overall, AFPs-WYH reduced the A. flavus proliferation and affected the AFB1 biosynthesis, exhibiting a promising potential for food industry applications as a biopreservative and biocontrol agent.

High-quality genome resource of Lasiodiplodia pseudotheobromae associated with die-back on Eucalyptus trees

OBJECTIVES

Lasiodiplodia pseudotheobromae is an important fungal pathogen associated with die-back, canker and shoot blight in many plant hosts with a wide geographic distribution. The aim of our study was to provide high-quality genome assemblies and sequence annotation resources of L. pseudotheobromae, to facilitate future studies on the systematics, population genetics and genomics of the fungal pathogen L. pseudotheobromae.

DATA DESCRIPTION

High-quality genomes of five L. pseudotheobromae isolates were sequenced based on Oxford Nanopore technology (ONT) and Illumina HiSeq sequencing platform. The total size of each assembly ranged from 43 Mb to 43.86 Mb and over 11,000 protein-coding genes were predicted from each genome. The proteins of predicted genes were annotated using multiple public databases, among the annotated protein-coding genes, more than 4,300 genes were predicted as potential virulence genes by the Pathogen Host Interactions (PHI) database. Moreover, the genome comparative analysis among L. pseudotheobromae and other closely related species revealed that 7,408 gene clusters were shared among them and 152 gene clusters unique to L. pseudotheobromae. This genome and associated datasets provided here will serve as a useful resource for further analyses of this fungal pathogen species.

Functional genome analysis and anti-Helicobacter pylori activity of a novel bacteriocinogenic Lactococcus sp. NH2-7C from Thai fermented pork (Nham)

Helicobacter pylori, linked to gastric diseases, is targeted for probiotic treatment through bacteriocin production. Bacteriocins have gained recognition for their non-toxic effects on host cells and their ability to combat a wide range of pathogens. This study aimed to taxonomically characterize and evaluate the safety and probiotic properties of the novel species of Lactococcus sp. NH2-7C isolated from fermented pork, as well as its bacteriocin NH2-7C, both in vitro and in silico. Comparative genotypic analysis revealed an average nucleotide identity of 94.96%, an average amino acid identity of 94.29%, and a digital DNA-DNA hybridization value of 63.80% when compared to Lactococcus lactis subsp. lactis JCM 5805T. These findings suggest that strain NH2-7C represents a novel species within the genus Lactococcus. In silico assessments confirmed the non-pathogenic nature of strain NH2-7C and the absence of genes associated with virulence and biogenic amine formation. Whole-genome analysis revealed the presence of the nisA gene responsible for nisin A production, indicating its potential as a beneficial compound with anti-Helicobacter pylori activity and non-toxic characteristics. Probiotic assessments indicated bile salt hydrolase and cholesterol assimilation activities, along with the modulation of interleukin-6 and tumour necrosis factor-α secretion. Strain NH2-7C demonstrated gastrointestinal tolerance and the ability to adhere to Caco-2 cells, affirming its safety and probiotic potential. Additionally, its ability to produce bacteriocins supports its suitability as a functional probiotic strain with therapeutic potential. However, further in vitro and in vivo investigations are crucial to ensure its safety and explore potential applications for Lactococcus sp. NH2-7C as a probiotic agent.

Genome-Assisted Probiotic Characterization and Application of Lactiplantibacillus plantarum 18 as a Candidate Probiotic for Laying Hen Production

Probiotics gained significant attention for their potential to improve gut health and enhance productivity in animals, including poultry. This comprehensive study focused on the genetic analysis of Lactiplantibacillus plantarum 18 (LP18) to understand its survival and colonization characteristics in the gastrointestinal tract. LP18 was supplemented in the late-stage diet of laying hens to investigate its impact on growth performance, egg quality, and lipid metabolism. The complete genome sequence of LP18 was determined, consisting of 3,275,044 base pairs with a GC content of 44.42% and two circular plasmids. Genomic analysis revealed genes associated with adaptability, adhesion, and gastrointestinal safety. LP18 supplementation significantly improved the daily laying rate (p < 0.05) during the late-production phase and showed noteworthy advancements in egg quality, including egg shape index (p < 0.05), egg albumen height (p < 0.01), Haugh unit (p < 0.01), and eggshell strength (p < 0.05), with notable improvements in eggshell ultrastructure. Additionally, LP18 supplementation resulted in a significant reduction in serum lipid content, including LDL (p < 0.01), FFA (p < 0.05), and Gly (p < 0.05). These findings provide valuable insights into the genomic characteristics of LP18 and the genes that support its survival and colonization in the gastrointestinal tract. Importantly, this study highlights the potential of LP18 as a probiotic candidate to enhance productivity, optimize egg quality, and modulate lipid metabolism in poultry production.

Oxidative Stress Response of Probiotic Strain Bifidobacterium longum subsp. longum GT15

Bifidobacterium is a predominant and important genus in the bacterial population of the human gut microbiota. Despite the increasing number of studies on the beneficial functionality of bifidobacteria for human health, knowledge about their antioxidant potential is still insufficient. Several in vivo and in vitro studies of Bifidobacterium strains and their cellular components have shown good antioxidant capacity that provided a certain protection of their own and the host's cells. Our work presents the data of transcriptomic, proteomic, and metabolomic analyses of the growing and stationary culture of the probiotic strain B. longum subsp. longum GT15 after exposure to hydrogen peroxide for 2 h and oxygen for 2 and 4 h. The results of the analysis of the sequenced genome of B. longum GT15 showed the presence of 16 gene-encoding proteins with known antioxidant functions. The results of the full transcriptomic analysis demonstrated a more than two-fold increase of levels of transcripts for eleven genes, encoding proteins with antioxidant functions. Proteomic data analysis showed an increased level of more than two times for glutaredoxin and thioredoxin after the exposure to oxygen, which indicates that the thioredoxin-dependent antioxidant system may be the major redox homeostasis system in B. longum bacteria. We also found that the levels of proteins presumably involved in global stress, amino acid metabolism, nucleotide and carbohydrate metabolism, and transport had significantly increased in response to oxidative stress. The metabolic fingerprint analysis also showed good discrimination between cells responding to oxidative stress and the untreated controls. Our results provide a greater understanding of the mechanism of oxidative stress response in B. longum and the factors that contribute to its survival in functional food products.

Whole Genome Sequence of Lactiplantibacillus plantarum HOM3204 and Its Antioxidant Effect on D-Galactose-Induced Aging in Mice

Lactiplantibacillus plantarum, previously named Lactobacillus plantarum, is a facultative, homofermentative lactic acid bacterium widely distributed in nature. Several Lpb. plantarum strains have been demonstrated to possess good probiotic properties, and Lpb. plantarum HOM3204 is a potential probiotic strain isolated from homemade pickled cabbage plants. In this study, whole-genome sequencing was performed to acquire genetic information and predict the function of HOM3204, which has a circular chromosome of 3,232,697 bp and two plasmids of 48,573 and 17,060 bp, respectively. Moreover, various oxidative stress-related genes were identified in the strain, and its antioxidant activity was evaluated in vitro and in vivo. Compared to reference strains, the intracellular cell-free extracts of Lpb. plantarum HOM3204 at a dose of 1010 colony-forming units (CFU)/ml in vitro exhibited stronger antioxidant properties, such as total antioxidant activity, 2,2-diphenyl-1-picrylhydrazyl radical scavenging rate, superoxide dismutase activity, and glutathione (GSH) content. Daily administration of 109 CFU Lpb. plantarum HOM3204 for 45 days significantly improved the antioxidant function by increasing the glutathione peroxidase activity in the whole blood and GSH concentration in the livers of D-galactose-induced aging mice. These results suggest that Lpb. plantarum HOM3204 can potentially be used as a food ingredient with good antioxidant properties.

Whole-genome sequence analysis and probiotic characteristics of Lactococcus lactis Subsp. lactis strain Lac3 isolated from traditional fermented buffalo milk (Dadih)

BACKGROUND

Probiotics are live microorganisms that provide beneficial effects on the host's health when exploited in adequate amounts. This study aimed at carrying out whole-genome sequence analysis and in vitro potential probiotic characteristics of Lactococcus lactis subsp. lactis strain Lac3 isolated from the spontaneously fermented buffalo milk named Dadih.

RESULTS

The results from de novo assembly indicated that the assembled genome consisted of 55 contigs with a genome size of 2,441,808 bp ~ (2.44 Mb), and GC % content of 34.85%. The evolution history result showed that the strain Lac3 was closely related to Lactococcus lactis species deposited in NCBI with a sequence similarity ≥ 99.93%. L. lactis subsp. lactis Lac3 was non-pathogenic with a probability of 0.21 out of 1 and had a pathogenicity score of zero (0), and neither harbored virulence factors nor acquired antibiotic resistance phenotypes. L. lactis subsp. lactis Lac3 exhibited the potential probiotic characteristics to tolerate acid at pH (2.0 and 5.0), salinity (1-5% NaCl), bile salt of (0.3-1.0%) and had auto-aggregation capacity increased from 6.0 to 13.1%.

CONCLUSION

This study described a novel strain of Lactococcus lactis subsp. lactis called Lac3, which exhibits probiotic properties that could be beneficial in the development of probiotics.

Assessing the Safety and Probiotic Characteristics of Lacticaseibacillus rhamnosus X253 via Complete Genome and Phenotype Analysis

Lacticaseibacillus rhamnosus is a generalist that can adapt to different ecological niches, serving as a valuable source of probiotics. The genome of L. rhamnosus X253 contains one chromosome and no plasmids, with a size of 2.99 Mb. Both single-copy orthologous gene-based phylogenetic analysis and average nucleotide identity indicated that dairy-derived L. rhamnosus X253 was most closely related to the human-intestine-derived strain L. rhamnosus LOCK908, rather than other dairy strains. The adaptation of L. rhamnosus X253 and the human-intestine-derived strain L. rhamnosus GG to different ecological niches was explained by structural variation analysis and COG annotation. Hemolytic assays, API ZYM assays, and antimicrobial susceptibility tests were performed to validate risk-related sequences such as virulence factors, toxin-encoding genes, and antibiotic-resistance genes in the genomes of L. rhamnosus X253 and GG. The results showed that L. rhamnosus GG was able to use L-fucose, had a higher tolerance to bile salt, and adhered better to CaCo-2 cells. In contrast, L. rhamnosus X253 was capable of utilizing D-lactose, withstood larger quantities of hydrogen peroxide, and possessed excellent antioxidant properties. This study confirmed the safety and probiotic properties of L. rhamnosus X253 via complete genome and phenotype analysis, suggesting its potential as a probiotic.

Probiogenomic In-Silico Analysis and Safety Assessment of Lactiplantibacillus plantarum DJF10 Strain Isolated from Korean Raw Milk

The whole genome sequence of Lactiplantibacillus plantarum DJF10, isolated from Korean raw milk, is reported, along with its genomic analysis of probiotics and safety features. The genome consists of 29 contigs with a total length of 3,385,113 bp and a GC content of 44.3%. The average nucleotide identity and whole genome phylogenetic analysis showed the strain belongs to Lactiplantibacillus plantarum with 99% identity. Genome annotation using Prokka predicted a total of 3235 genes, including 3168 protein-coding sequences (CDS), 59 tRNAs, 7 rRNAs and 1 tmRNA. The functional annotation results by EggNOG and KEGG showed a high number of genes associated with genetic information and processing, transport and metabolism, suggesting the strain's ability to adapt to several environments. Various genes conferring probiotic characteristics, including genes related to stress adaptation to the gastrointestinal tract, biosynthesis of vitamins, cell adhesion and production of bacteriocins, were identified. The CAZyme analysis detected 98 genes distributed under five CAZymes classes. In addition, several genes encoding carbohydrate transport and metabolism were identified. The genome also revealed the presence of insertion sequences, genomic islands, phage regions, CRISPR-cas regions, and the absence of virulence and toxin genes. However, the presence of hemolysin and antibiotic-resistance-related genes detected in the KEGG search needs further experimental validation to confirm the safety of the strain. The presence of two bacteriocin clusters, sactipeptide and plantaricin J, as detected by the BAGEL 4 webserver, confer the higher antimicrobial potential of DJF10. Altogether, the analyses in this study performed highlight this strain's functional characteristics. However, further in vitro and in vivo studies are required on the safety assurance and potential application of L. plantarum DJF10 as a probiotic agent.

Complete Genome Sequence of Lactobacillus salivarius AR809, a Probiotic Strain with Oropharyngeal Tract Resistance and Adhesion to the Oral Epithelial Cells

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 H₂O₂. 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.

Mechanism of gastrointestinal adaptability and antioxidant function of infant-derived Lactobacillus plantarum BF_15 through genomics

Lactobacillus plantarum is an essential probiotic in the human gastrointestinal tract. L. plantarum BF_15, a functional probiotic isolated from the feces of breast-fed infants, has been reported in many in vitro and in vivo studies with strong gastrointestinal adaptability and outstanding anti-oxidative activities. Therefore, the whole genome of L. plantarum BF_15 was sequenced. Several genes, encoding the gastrointestinal adaptability-related proteins, were identified, including genes related to gastrointestinal environment-induced stress resistance, adhesive performance, and ability to transport and metabolize resistant starch and oligosaccharides. Genes related to alleviating oxidative stress were also found. Further functional verification was carried out by RT-qPCR on the 10 and 12 key adhesion and antioxidant genes. Overall, this study might provide a critical basis for L. plantarum BF_15 as a potential candidate for probiotics.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01132-w.

Saccharomyces cerevisiae I4 Showed Alleviating Effects on Dextran Sulfate Sodium-Induced Colitis of Balb/c Mice

Ulcerative colitis (UC) is a chronic inflammatory bowel disease. The purpose of this study was to investigate the ameliorating effects of three yeast strains, Saccharomyces cerevisiae I4, Clavispora lusitaniae 30 and Pichia kudriavzevii 11, isolated from traditional fermented dairy food in Xinjiang, China, on the ulcerative colitis symptoms of Balb/c mice treated by dextran sulfate sodium (DSS). Among which, S. cerevisiae I4 had good tolerance to simulated gastrointestinal juice and strong adhesion to HT–29 cells monolayers. Furthermore, the three yeast strains were oral administered to Balb/c mice with DSS induced colitis. The weight loss, colon shortening and histological injury of colitis mice were ameliorated. Then, oral administration of S. cerevisiae I4 improved the immune state by reducing the contents of TNF–α, IL–6 and IL–1β and increasing immunoglobulin. The relative expression of intestinal barrier proteins Claudin–1, Occludin and Zonula Occludins–1 (ZO–1) of the mice enhanced, and the short chain fatty acids (SCFAs) content such as Propionic acid, Butyric acid, Isobutyric acid and Isovaleric acid in the feces of the mice increased to varying degrees, after S. cerevisiae I4 treatment compared with the model group of drinking 3% DSS water without yeast treatment. Moreover, S. cerevisiae I4 treatment lifted the proportion of beneficial bacteria such as Muribaculaceae, Lactobacillaceae and Rikenellaceae in the intestinal tract of the mice, the abundance of harmful bacteria such as Staphylococcus aureus and Turicibacter was decreased. These results suggested that S. cerevisiae I4 could alleviate DSS induced colitis in mice by enhancing intestinal barrier function and regulating intestinal flora balance.

Assessments of Probiotic Potentials of Lactiplantibacillus plantarum Strains Isolated From Chinese Traditional Fermented Food: Phenotypic and Genomic Analysis

The lack of rapid and effective approaches to determine the health benefits of strains is one of the main challenges affecting the selection of probiotics from large numbers of candidates. In this study, the probiotic potential of 44 Lactiplantibacillus plantarum strains isolated from different Chinese traditional fermented foods was evaluated, including acid and bile salt resistance, adhesion ability, survival in simulated human gastrointestinal transit, antioxidant activity, bile salt hydrolase (BSH) activity, and antibacterial activity. All tested L. plantarum strains showed high antioxidant capacity, BSH activity, and antibacterial activity. Among the strains, B652, C232, D444, and E932 were identified as the best comprehensive performed strains, which were selected for whole-genome sequencing, in order to provide clear information and identify key genes responsible for functional characteristics in vitro. It demonstrated that the antioxidant activity, adhesion activity, and ability to survive in the simulated gastric environment were found to be closely correlated with antioxidant enzyme encoding genes, cell-surface protein-encoding genes, and stress response genes, respectively. The numbers of functional genes present in strains might decide their performance in probiotic profile evaluation. The outcome of the study could support the development of a novel approach for the screening and identification of probiotics.

The Carbohydrate Metabolism of Lactiplantibacillus plantarum

Lactiplantibacillus plantarum has a strong carbohydrate utilization ability. This characteristic plays an important role in its gastrointestinal tract colonization and probiotic effects. L. plantarum LP-F1 presents a high carbohydrate utilization capacity. The genome analysis of 165 L. plantarum strains indicated the species has a plenty of carbohydrate metabolism genes, presenting a strain specificity. Furthermore, two-component systems (TCSs) analysis revealed that the species has more TCSs than other lactic acid bacteria, and the distribution of TCS also shows the strain specificity. In order to clarify the sugar metabolism mechanism under different carbohydrate fermentation conditions, the expressions of 27 carbohydrate metabolism genes, catabolite control protein A (CcpA) gene ccpA, and TCSs genes were analyzed by quantitative real-time PCR technology. The correlation analysis between the expressions of regulatory genes and sugar metabolism genes showed that some regulatory genes were correlated with most of the sugar metabolism genes, suggesting that some TCSs might be involved in the regulation of sugar metabolism.

High-quality whole-genome sequence analysis of Lactobacillus paragasseri UBLG-36 reveals oxalate-degrading potential of the strain

Lactobacillus paragasseri was identified as a novel sister taxon of L. gasseri in 2018. Since the reclassification of L. paragasseri, there has been hardly any report describing the probiotic properties of this species. In this study, an L. paragasseri strain UBLG-36 was sequenced and analyzed to determine the molecular basis that may confer the bacteria with probiotic potential. UBLG-36 was previously documented as an L. gasseri strain. Average nucleotide identity and phylogenomic analysis allowed accurate taxonomic identification of UBLG-36 as an L. paragasseri strain. Analysis of the draft genome (~1.94 Mb) showed that UBLG-36 contains 5 contigs with an average G+C content of 34.85%. Genes essential for the biosynthesis of bacteriocins, adhesion to host epithelium, stress resistance, host immunomodulation, defense, and carbohydrate metabolism were identified in the genome. Interestingly, L. paragasseri UBLG-36 also harbored genes that code for enzymes involved in oxalate catabolism, such as formyl coenzyme A transferase (frc) and oxalyl coenzyme A decarboxylase (oxc). In vitro oxalate degradation assay showed that UBLG-36 is highly effective in degrading oxalate (averaging more than 45% degradation), a feature that has not been reported before. As a recently identified bacterium, there are limited genomic reports on L. paragasseri, and our draft genome sequence analysis is the first to describe and emphasize the probiotic potential and oxalate degrading ability of this species. With results supporting the probiotic functionalities and oxalate catabolism of UBLG-36, we propose that this strain is likely to have immense biotechnological applications upon appropriate characterization.

Biomarkers and Utility of the Antioxidant Potential of Probiotic Lactobacilli and Bifidobacteria as Representatives of the Human Gut Microbiota

Lactobacilli and bifidobacteria are an important part of human gut microbiota. Among numerous benefits, their antioxidant properties are attracting more and more attention. Multiple in vivo and in vitro studies have demonstrated that lactobacilli and bifidobacteria, along with their cellular components, possess excellent antioxidant capacity, which provides a certain degree of protection to the human body against diseases associated with oxidative stress. Recently, lactobacilli and bifidobacteria have begun to be considered as a new source of natural antioxidants. This review summarizes the current state of research on various antioxidant properties of lactobacilli and bifidobacteria. Special emphasis is given to the mechanisms of antioxidant activity of these bacteria in the human gut microbiota, which involve bacterial cell components and metabolites. This review is also dedicated to the genes involved in the antioxidant properties of lactobacilli and bifidobacteria strains as indicators of their antioxidant potential in human gut microbiota. Identification of the antioxidant biomarkers of the gut microbiota is of great importance both for creating diagnostic systems for assessing oxidative stress and for choosing strategies aimed at restoring the normal functioning of the microbiota and, through it, restoring human health. In this review, the practical application of probiotic strains with proven antioxidant properties to prevent oxidative stress is also considered.

Lactobacillus paracasei HY7015 Promotes Hair Growth in a Telogenic Mouse Model

In this study, we describe the effects of Lactobacillus paracasei HY7015 (HY7015) on promoting mouse hair growth. Since our purpose was to increase hair growth through oral administration, medicinal yeast, at a suitable concentration for application in mice, was used as a positive control. First, experiments were conducted to determine the effect of HY7015 on proliferation of hair follicle dermal papilla cells (HFDPC), which are important contributors to hair growth. HY7015 stimulated HFDPC proliferation in vitro and increased their secretion of vascular endothelial growth factor and insulin-like growth factor-1. In mouse experiments, oral administration of HY7015 promoted hair growth and hair follicle maturation in the dorsal skin, as well as increasing growth factor levels in mouse serum. In summary, we demonstrate that L. paracasei HY7015 consumption can promote hair growth by stimulating HFDPC proliferation and growth factor secretion. Follow-up studies are warranted to determine the underlying mechanism, using various approaches, including investigation of changes in intestinal microbiota and alteration of gene and protein expression.

Genome and Pangenome Analysis of Lactobacillus hilgardii FLUB-A New Strain Isolated from Mead

The production of mead holds great value for the Polish liquor industry, which is why the bacterium that spoils mead has become an object of concern and scientific interest. This article describes, for the first time, Lactobacillus hilgardii FLUB newly isolated from mead, as a mead spoilage bacteria. Whole genome sequencing of L. hilgardii FLUB revealed a 3 Mbp chromosome and five plasmids, which is the largest reported genome of this species. An extensive phylogenetic analysis and digital DNA-DNA hybridization confirmed the membership of the strain in the L. hilgardii species. The genome of L. hilgardii FLUB encodes 3043 genes, 2871 of which are protein coding sequences, 79 code for RNA, and 93 are pseudogenes. L. hilgardii FLUB possesses three clustered regularly interspaced short palindromic repeats (CRISPR), eight genomic islands (44,155 bp to 6345 bp), and three (two intact and one incomplete) prophage regions. For the first time, the characteristics of the genome of this species were described and a pangenomic analysis was performed. The concept of the pangenome was used not only to establish the genetic repertoire of this species, but primarily to highlight the unique characteristics of L. hilgardii FLUB. The core of the genome of L. hilgardii is centered around genes related to the storage and processing of genetic information, as well as to carbohydrate and amino acid metabolism. Strains with such a genetic constitution can effectively adapt to environmental changes. L. hilgardii FLUB is distinguished by an extensive cluster of metabolic genes, arsenic detoxification genes, and unique surface layer proteins. Variants of MRS broth with ethanol (10-20%), glucose (2-25%), and fructose (2-24%) were prepared to test the strain's growth preferences using Bioscreen C and the PYTHON script. L. hilgardii FLUB was found to be more resistant than a reference strain to high concentrations of alcohol (18%) and sugars (25%). It exhibited greater preference for fructose than glucose, which suggests it has a fructophilic nature. Comparative genomic analysis supported by experimental research imitating the conditions of alcoholic beverages confirmed the niche specialization of L. hilgardii FLUB to the mead environment.

High-quality whole-genome sequence analysis of Lactobacillus paragasseri UBLG-36 reveals oxalate-degrading potential of the strain

Lactobacillus paragasseri was identified as a novel sister taxon of L. gasseri in 2018. Since the reclassification of L. paragasseri, there has been hardly any report describing the probiotic properties of this species. In this study, an L. paragasseri strain UBLG-36 was sequenced and analyzed to determine the molecular basis that may confer the bacteria with probiotic potential. UBLG-36 was previously documented as an L. gasseri strain. Average nucleotide identity and phylogenomic analysis allowed accurate taxonomic identification of UBLG-36 as an L. paragasseri strain. Analysis of the draft genome (~1.94 Mb) showed that UBLG-36 contains 5 contigs with an average G+C content of 34.85%. Genes essential for the biosynthesis of bacteriocins, adhesion to host epithelium, stress resistance, host immunomodulation, defense, and carbohydrate metabolism were identified in the genome. Interestingly, L. paragasseri UBLG-36 also harbored genes that code for enzymes involved in oxalate catabolism, such as formyl coenzyme A transferase (frc) and oxalyl coenzyme A decarboxylase (oxc). In vitro oxalate degradation assay showed that UBLG-36 is highly effective in degrading oxalate (averaging more than 45% degradation), a feature that has not been reported before. As a recently identified bacterium, there are limited genomic reports on L. paragasseri, and our draft genome sequence analysis is the first to describe and emphasize the probiotic potential and oxalate degrading ability of this species. With results supporting the probiotic functionalities and oxalate catabolism of UBLG-36, we propose that this strain is likely to have immense biotechnological applications upon appropriate characterization.

Complete Genome and Comparative Genome Analysis of Lactobacillus reuteri YSJL-12, a Potential Probiotics Strain Isolated From Healthy Sow Fresh Feces

Lactobacillus reuteri YSJL-12 was isolated from healthy sow fresh feces and used as probiotics additives previously. To investigate the genetic basis on probiotic potential and identify the genes in the strain, the complete genome of YSJL-12 was sequenced. Then comparative genome analysis on 9 strains of Lactobacillus reuteri was performed. The genome of YSJL-12 consisted of a circular 2,084,748 bp chromosome and 2 circular plasmids (51,906 and 15,134 bp). From among the 2065 protein-coding sequences (CDSs), the genes resistant to the environmental stress were identified. The function of COG (Clusters of Orthologous Group) protein genes was predicted, and the KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways were analyzed. The comparative genome analysis indicated that the pan-genome contained a core genome of 1257 orthologous gene clusters, an accessory genome of 1064 orthologous gene clusters, and 1148 strain-specific genes, and the antibacterial mechanism among Lactobacillus reuteri strains might be different. The phylogenetic analysis and genomic collinearity revealed that the phylogenetic relationship among 9 strains of Lactobacillus reuteri was connected with host species and showed host specificity. The research could help us to better predict genes function and understand genetic basis on adapting to host gut in Lactobacillus reuteri YSJL-12.

Selection of Exopolysaccharide-Producing Lactobacillus Plantarum (Lactiplantibacillus Plantarum) Isolated from Algerian Fermented Foods for the Manufacture of Skim-Milk Fermented Products

The exopolysaccharide (EPS)-producing Lactobacillus plantarum (renamed as Lactiplantibacillus plantarum) LBIO1, LBIO14 and LBIO28 strains, isolated from fermented dairy products typical from Algeria, were characterized to evaluate the impact of the polymers in milk fermentations. Their genomes revealed the presence of two complete eps clusters of the four described for the reference strain WCFS1. Besides, the three strains presented identical sequences of eps3 and eps4 clusters, but LBIO1 and LBIO28 harbour three genes belonging to eps2 which are absent in the LBIO14 genome. The EPS purified from fermented skim-milks manufactured with the strains showed identical nuclear magnetic resonance (1H-NMR) and size exclusion chromatography coupled with a multiangle laser light scattering detector (SEC-MALLS) profiles for polymers LBIO1 and LBIO28, whereas LBIO14 EPS was different due to the lack of the high-molecular weight (HMW)-EPS and the absence of specific monosaccharide's peaks in the anomeric region of its proton NMR spectrum. The presence of the HMW-EPS correlated with optimal sensorial-physical characteristics of the fermented skim-milks (ropy phenotype). Their microstructures, studied by confocal scanning laser microscopy (CSLM), also showed differences in the organization of the casein-network and the distribution of the bacteria inside this matrix. Therefore, the strain LBIO1 can be proposed for the manufacture of dairy products that require high whey retention capability, whereas LBIO28 could be applied to increase the viscosity.

Characterization of a potential probiotic bacterium Lactococcus raffinolactis WiKim0068 isolated from fermented vegetable using genomic and in vitro analyses

Background

Lactococcus members belonging to lactic acid bacteria are widely used as starter bacteria in the production of fermented dairy products. From kimchi, a Korean food made of fermented vegetables, Lactococcus raffinolactis WiKim0068 was isolated and its genome was analyzed.

Results

The complete genome of the strain WiKim0068 consists of one chromosome and two plasmids that comprises 2,292,235 bp, with a G + C content of 39.7 mol%. Analysis of orthoANI values among Lactococcus genome sequences showed that the strain WiKim0068 has > 67% sequence similarity to other species and subspecies. In addition, it displayed no antibiotic resistance and can metabolize nicotinate and nicotinamide (vitamin B3).

Conclusion

These results augments our understanding of the genus Lactococcus and suggest that this new strain has potential industrial applications.

Complete genome sequence analysis of a strain Lactobacillus pentosus ZFM94 and its probiotic characteristics

Lactic acid bacteria have been attracting increased attentions recent years because of harboring probiotic properties. In present study, a Lactobacillus pentosus strain ZFM94 was screened from healthy infant feces and its probiotic characteristics were investigated. We found that ZFM94 was resistant to environmental stresses (temperature, pH and NaCl), tolerant to gastrointestinal juice and bile salts, with inhibitory action against pathogens and capacity of folate production etc. Additionally, complete genome sequence of the strain was analyzed to highlight the probiotic features at genetic level. Genomic characteristics along with the experimental studies is critically important for building an appropriate probiotic profile of novel strains. Genes that correspond to phenotypes mentioned above were identified. Moreover, genes potentially related to its adaptation, such as carbon metabolism and carbohydrate transporter, carbohydrate-active enzymes, and a novel gene cluster RaS-RiPPs, were also revealed. Together, ZFM94 could be considered as a potential probiotic candidate.

Physiological function analysis of Lactobacillus plantarum Y44 based on genotypic and phenotypic characteristics

In our previous studies, Lactobacillus plantarum Y44 showed antioxidant activity and favorable gastric and intestinal transit tolerance. In the current study, we investigated the physiological function of L. plantarum Y44 based on an analysis of its genotype and phenotype. The complete genome of L. plantarum Y44 contained a single circular chromosome of 3,255,555 bp, with a GC content of 44.6%, and a single circular plasmid of 51,167 bp, with a GC content of 38.8%. The L. plantarum Y44 genome contained 3,293 genes including 3,112 protein coding sequences, 16 rRNAs, 66 tRNAs, 4 small (s)RNAs, and 95 pseudo genes. Lactobacillus plantarum Y44 could metabolize 24 different carbohydrate sources. Nineteen complete phosphoenolpyruvate-dependent sugar phosphotransferase system complex genes and intact Embden-Meyerhof-Parnas pathway and hexose monophosphate pathway enzyme genes, as well as abundant carbohydrate active enzyme genes, were identified in the L. plantarum Y44 genome. We also identified genes related to the biosynthesis of exopolysaccharide and surface proteins. Surface proteins played an important role in the L. plantarum Y44 adhesion to HT-29 cell monolayers, as evidenced by the removal of cell surface proteins leading to decreased adhesion capacity. The L. plantarum Y44 genome contained genes encoding chaperones, intracellular proteases, and 2-component systems, which were associated with the general stress response. Genes encoding bile salt hydrolase, F₀F₁-ATPase, Na⁺/H⁺-antiporter, H⁺/Cl^- exchange transporter, cyclopropane-fatty acyl-phospholipid synthase, and alkaline shock protein were identified in the L. plantarum Y44 genome, which might explain the strain's favorable gastric and intestinal transit tolerance. Some genes associated with encoding the NADH system, glutathione system, and thioredoxin system were predicted via in silico analysis and might account for the strain's ability to scavenge reactive oxygen species. Lactobacillus plantarum Y44 was susceptive to 7 antibiotics and did not produce biogenic amines, likely due to the absence of acquired antibiotic resistance genes and amino acid decarboxylase genes. The phenotype profile of L. plantarum Y44 was associated with its genetic characteristics, indicating that strains with certain physiological functions can be screened by analyzing their phenotypic and genotypic characteristics. Lactobacillus plantarum Y44 has the potential to be used as a starter culture in fermented dairy products.

Next-generation sequencing to elucidate adaptive stress response and plantaricin genes among Lactobacillus plantarum strains

Aim: The objective of this study was to identify the genes involved in plantaricin synthesis and adaptive stress response in four Lactobacillus plantarum strains (AS-6, AS-8, AS-9 and AS-10) and one Lactobacillus paraplantarum strain (AS-7) for their usage in medicine and industry. Materials & methods: Whole genomes of these strains were sequenced by a high-throughput sequencing technique known as next-generation sequencing via Ilumina MiSeq platform and the genes were identified by using various bioinformatics tools and software. Results: Plantaricin genes (plnD, plnE, plnF, plnG, plnI) and genes regulating response to temperature, pH, bile salt, osmotic and oxidative stress were identified in all strains. Conclusion: Lactobacilli could be an option to combat antimicrobial resistance and might replace harmful antibiotics in future.

Screening of Bacteriocinogenic Lactic Acid Bacteria and Their Characterization as Potential Probiotics

Probiotics are living microorganisms used as nutritional additives that confer health benefits on the host. Their use in food products is very attractive, especially if they could also inhibit important foodborne pathogens. In this study, antimicrobial activity against several foodborne pathogens was screened for 280 lactic acid bacteria (LAB) isolated from different food products and the probiotic characteristics of bacteriocinogenic isolates were evaluated. Seven out of 280 LAB isolates were selected due to their bacteriocinogenic properties and identified by 16S rRNA gene sequence analysis as Pediococcus pentosaceus (n = 6) and Lactobacillus plantarum (n = 1). Virulence factors and antibiotic resistances were not detected for any of the isolates. Except for L. plantarum R23, all the isolates were able to survive through the simulated gastrointestinal tract conditions. Only P. pentosaceus CFF4 was able to adhere to Caco-2 cells after the simulated gastrointestinal tract passage. In conclusion, even though in vivo studies should be performed, P. pentosaceus CFF4, which was also able to inhibit the growth of foodborne pathogens in vitro, seems to be a potential probiotic to be used in the food industry.

Genomic Insights Into Five Strains of Lactobacillus plantarum With Biotechnological Potential Isolated From chicha, a Traditional Maize-Based Fermented Beverage From Northwestern Argentina

Lactic acid bacteria (LAB) are indigenous microorganisms that have been involved in food fermentations throughout history to preserve food and also to give special characteristics to them. The traditional fermented foods that are still being elaborated in indigenous populations around the world are a potential source of LAB with important biotechnological properties and/or beneficial to health. In a previous work, LAB biodiversity associated with chicha, a traditional maize-based fermented beverage from Northwestern Argentina, was studied, both by culture dependent and independent methods. From that study, 392 isolates were recovered, mostly members of Lactobacillus and Leuconostoc. Biotechnological characterization of representative isolates led to the selection of five strains belonging to the species Lactobacillus plantarum for their ability to produce vitamin B2 (riboflavin) and vitamin B9 (folates), their antimicrobial properties and antibiotics susceptibility. In this work, we present the Whole Genome Sequences (WGS) of these five strains that have been deposited in the Spanish Type Culture Collection: M5MA1 (= CECT 8962), M9MM1 (= CECT 8963), M9MM4 (= CECT 8964), M9MG6 (= CECT 8965), and M9Y2 (= CECT 8966), and a detailed description of their characterization, through a genomic approach, analyzing the genes responsible for these biotechnological properties, making a comparative study of the five genomes and reporting the aspects related to food safety, in accordance with the recommendations of the European Food Safety Authority (EFSA FEEDAP Panel, 2018) aiming at their use in the design of functional foods. The analysis unveiled, for the five strains, the complete set of genes for folate and riboflavin biosynthesis, the absence of pathogenic factors, the presence of CRISPR and cas genes, phage sequences, insertion elements and an aminoglycosides resistance gene, aadA, whose resistance could not be proved phenotypically in any strain. Genomic comparisons showed that strain CECT 8962 was significantly different in terms of genetic content and allowed the identification of carbohydrates metabolism and membrane transport related genes as the main components of the unique and accessory genome.

Complete Genome Sequencing and Comparative Genome Characterization of Lactobacillus johnsonii ZLJ010, a Potential Probiotic With Health-Promoting Properties

Lactobacillus johnsonii ZLJ010 is a probiotic strain isolated from the feces of a healthy sow and has putative health-promoting properties. To determine the molecular basis underlying the probiotic potential of ZLJ010 and the genes involved in the same, complete genome sequencing and comparative genome analysis with L. johnsonii ZLJ010 were performed. The ZLJ010 genome was found to contain a single circular chromosome of 1,999,879 bp with a guanine-cytosine (GC) content of 34.91% and encoded 18 ribosomal RNA (rRNA) genes and 77 transfer RNA (tRNA) genes. From among the 1,959 protein coding sequences (CDSs), genes known to confer probiotic properties were identified, including genes related to stress adaptation, biosynthesis, metabolism, transport of amino acid, secretion, and the defense machinery. ZLJ010 lacked complete or partial biosynthetic pathways for amino acids but was predicted to compensate for this with an enhanced transport system and some unique amino acid permeases and peptidases that allow it to acquire amino acids and other precursors exogenously. The comparative genomic analysis of L. johnsonii ZLP001 and seven other available L. johnsonii strains, including L. johnsonii NCC533, FI9785, DPC6026, N6.2, BS15, UMNLJ22, and PF01, revealed 2,732 pan-genome orthologous gene clusters and 1,324 core-genome orthologous gene clusters. Phylogenomic analysis based on 1,288 single copy genes showed that ZLJ010 had a closer relationship with the BS15 from yogurt and DPC6026 from the porcine intestinal tract but was located on a relatively standalone branch. The number of clusters of unique, strain-specific genes ranged from 42 to 185. A total of 219 unique genes present in the genome of L. johnsonii ZLJ010 primarily encoded proteins that are putatively involved in replication, recombination and repair, defense mechanisms, transcription, amino acid transport and metabolism, and carbohydrate transport and metabolism. Two unique prophages were predicted in the ZLJ010 genome. The present study helps us understand the ability of L. johnsonii ZLJ010 to better adapt to the gut environment and also its probiotic functionalities.

Assessment of the Antimicrobial Potentiality and Functionality of Lactobacillus plantarum Strains Isolated from the Conventional Inner Mongolian Fermented Cheese Against Foodborne Pathogens

Lactobacillus plantarum are amongst the diversified lactic acid bacteria (LAB) species which are being utilized abundantly in the food industry. Numerous L. plantarum strains have been reported to produce several antimicrobial compounds. Diacetyl, hydrogen peroxide, organic acids, as well as bacteriocins can also be exemplified by a variable spectrum of actions. The current study was intended to conduct the screening and characterization of antimicrobial prospective of L. plantarum from traditional Inner Mongolian fermented hard cheese. Foodborne pathogens, Salmonella typhimurium, Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus, were examined by using the Oxford cup technique and the mixed culture inhibition assays. The resulting analyses disclosed that L. plantarum KLDS1.0344 indicated broad antimicrobial spectrum against all selected pathogens as compared to other LAB used in this study. Additionally, the decrement of the pathogen population was observed up to 3.47 logs in mixed culture inhibition assays. L. plantarum KLDS 1.0344 acid production was recorded up to 71.8 ± 3.59 °D in mixed culture while antimicrobial particles released in cell free supernatants demonstrated bacteriocin-like characteristics showing substantial pH stability (2.0–6.0), proteolytic enzyme reduced the antibacterial activity (15.2 ± 0.6 mm–20.4 ± 0.8 mm), heat stability (20 min at 120 °C) against selected pathogens. Moreover, the spectrum range of antimicrobial peptides after the partial purification was decreased as compared to the crude bacteriocin-like compound. The SDS-PAGE analysis showed the molecular weight range of partially purified bacteriocin from 12 to 45 kDa. After analyzing the obtained data from the current experimentation showed that the capability of L. plantarum KLDS 1.0344 to oppose the pathogen growth in vitro relies on the occurrence of organic acids along with bacteriocin-like compounds proving L. plantarum KLDS 1.0344 as a potentially appropriate candidate as an alternative bio-control agent against foodborne pathogens.

Genomic analysis of Lactobacillus reuteri WHH1689 reveals its probiotic properties and stress resistance

Lactobacillus reuteri (L. reuteri) WHH1689, which was isolated from Chinese traditional highland barley wine, exhibited high survival period at room temperature in drinkable probiotic yogurt. This article aimed to indicate the genes involved in probiotic function of WHH1689 and reveal potential stress resistance based on genomic analysis. Analysis of comparative genome with closely related L. reuteri strains identified special stress adaptation. MUMmer and ACT softwares were applied for collinear analysis, and OrthoMCL program was used for sequence alignment involved in distribution of protein cluster. We identified genes coding for carbohydrate transport and enzymes, carbon metabolism pathway, gastrointestinal tract resistance, adhesive ability, and folic acid biosynthesis, etc. Genome sequence and comparative genome analysis of L. reuteri WHH1689 demonstrated specific genes for genetic adaptation and stress resistance. Tolerance, adhesion, and folate test indicated the strain had multiple probiotics. L. reuteri WHH1689 has the potential to be a probiotic candidate in dairy foods.

Dietary Nutrients, Proteomes, and Adhesion of Probiotic Lactobacilli to Mucin and Host Epithelial Cells

The key role of diet and environment in human health receives increasing attention. Thus functional foods, probiotics, prebiotics, and synbiotics with beneficial effects on health and ability to prevent diseases are in focus. The efficacy of probiotic bacteria has been connected with their adherence to the host epithelium and residence in the gut. Several in vitro techniques are available for analyzing bacterial interactions with mucin and intestinal cells, simulating adhesion to the host in vivo. Proteomics has monitored and identified proteins of probiotic bacteria showing differential abundance elicited in vitro by exposure to food components, including potential prebiotics (e.g., certain carbohydrates, and plant polyphenols). While adhesion of probiotic bacteria influenced by various environmental factors relevant to the gastrointestinal tract has been measured previously, this was rarely correlated with changes in the bacterial proteome induced by dietary nutrients. The present mini-review deals with effects of selected emerging prebiotics, food components and ingredients on the adhesion of probiotic lactobacilli to mucin and gut epithelial cells and concomitant abundancy changes of specific bacterial proteins. Applying this in vitro synbiotics-like approach enabled identification of moonlighting and other surface-located proteins of Lactobacillus acidophilus NCFM that are possibly associated with the adhesive mechanism.

Lactobacillus plantarum with Functional Properties: An Approach to Increase Safety and Shelf-Life of Fermented Foods

Lactobacillus plantarum (widespread member of the genus Lactobacillus) is one of the most studied species extensively used in food industry as probiotic microorganism and/or microbial starter. The exploitation of Lb. plantarum strains with their long history in food fermentation forms an emerging field and design of added-value foods. Lb. plantarum strains were also used to produce new functional (traditional/novel) foods and beverages with improved nutritional and technological features. Lb. plantarum strains were identified from many traditional foods and characterized for their systematics and molecular taxonomy, enzyme systems (α-amylase, esterase, lipase, α-glucosidase, β-glucosidase, enolase, phosphoketolase, lactase dehydrogenase, etc.), and bioactive compounds (bacteriocin, dipeptides, and other preservative compounds). This review emphasizes that the Lb. plantarum strains with their probiotic properties can have great effects against harmful microflora (foodborne pathogens) to increase safety and shelf-life of fermented foods.