Exopolysaccharide from Lacticaseibacillus rhamnosus induces IgA production in airways and alleviates allergic airway inflammation in mouse model.

The currently observed high prevalence of allergic diseases has been associated with changes in microbial exposure in industrialized countries. Defined bacterial components represent a new strategy for modulating the allergic immune response. We show that intranasal administration of exopolysaccharide (EPS) isolated from Lacticaseibacillus (L.) rhamnosus LOCK900 induces TGF-ß1, IgA, and regulatory FoxP3+ T-cells in the lungs of naïve mice. Using the ovalbumin mouse model, we demonstrate that intranasal administration of EPS downregulates the development of allergic airway inflammation and the Th2 cytokine response in sensitized individuals. At the same time, EPS treatment of sensitized mice, similar to EPS-induced responses in naïve mice, significantly increased the level of total, OVA-specific, and also bacteria-specific IgA in bronchoalveolar lavage and the number of IgA-producing B-cells in the lung tissue of these mice. Thus, EPS derived from L. rhamnosus LOCK900 can be considered a safe candidate for preventing the development of allergic symptoms in the lungs of sensitized individuals upon exposure to an allergen.

Lacticaseibacillus parahuelsenbergensis sp. nov., Lacticaseibacillus styriensis sp. nov. and Lacticaseibacillus zeae subsp. silagei subsp. nov., isolated from different grass and corn silage.

Four rod-shaped, non-motile, non-spore-forming, facultative anaerobic, Gram-stain-positive lactic acid bacteria, designated as EB0058T, SCR0080, LD0937T and SCR0063T, were isolated from different corn and grass silage samples. The isolated strains were characterized using a polyphasic approach and EB0058T and SCR0080 were identified as Lacticaseibacillus zeae by 16S rRNA gene sequence analysis. Based on whole-genome sequence-based characterization, EB0058T and SCR0080 were separated into a distinct clade from Lacticaseibacillus zeae DSM 20178T, together with CECT9104 and UD2202, whose genomic sequences are available from NCBI GenBank. The average nucleotide identity (ANI) values within the new subgroup are 99.9 % and the digital DNA-DNA hybridization (dDDH) values are 99.3-99.9 %, respectively. In contrast, comparison of the new subgroup with publicly available genomic sequences of L. zeae strains, including the type strain DSM 20178T, revealed dDDH values of 70.2-72.5 % and ANI values of 96.2-96.6 %. Based on their chemotaxonomic, phenotypic and phylogenetic characteristics, EB0058T and SCR0080 represent a new subspecies of L. zeae. The name Lacticaseibacillus zeae subsp. silagei subsp. nov. is proposed with the type strain EB0058T (=DSM 116376T=NCIMB 15474T). According to the results of 16S rRNA gene sequencing, LD0937T and SCR0063T are members of the Lacticaseibacillus group. The dDDH value between the isolates LD0937T and SCR0063T was 67.6 %, which is below the species threshold of 70 %, clearly showing that these two isolates belong to different species. For both strains, whole genome-sequencing revealed that the closest relatives within the Lacticaseibacillus group were Lacticaseibacillus huelsenbergensis DSM 115425 (dDDH 66.5 and 65.9 %) and Lacticaseibacillus casei DSM 20011T (dDDH 64.1 and 64.9 %). Based on the genomic, chemotaxonomic and morphological data obtained in this study, two novel species, Lacticaseibacillus parahuelsenbergensis sp. nov. and Lacticaseibacillus styriensis sp. nov. are proposed and the type strains are LD0937T (=DSM 116105T=NCIMB 15471T) and SCR0063T (=DSM 116297T=NCIMB 15473T), respectively.

Lacticaseibacillus pabuli sp. nov., isolated from fermented cattle feed.

Strain BSF-3MT is a Gram-stain-positive, non-flagellated, facultative anaerobic and rod-shaped bacterium that was isolated from fermented feed collected at a cattle farm in the Daejeon region of the Republic of Korea. It was studied using polyphasic taxonomic methods. Using 16S rRNA gene sequences and the resulting phylogenetic tree, the strain was primarily identified as a member of the genus Lacticaseibacillus. Strain BSF-3MT contained a chromosome of 2.5 Mbp and a plasmid of 33.4 kbp. The G+C content of genomic DNA was 51.3 mol%. Strain BSF-3MT had the highest ortho-average nucleotide identity value of 73.7 % with Lacticaseibacillus songhuajiangensis 7-19T, its closest relative in the phylogenetic tree based on the 16S rRNA gene sequences and the phylogenomic tree based on up-to-date bacterial core genes. Based on the results of a polyphasic taxonomic study, strain BSF-3MT represents a novel species in the genus Lacticaseibacillus, for which the name Lacticaseibacillus pabuli sp. nov. is proposed. The type strain is BSF-3MT (=KACC 23028T=NBRC 116014T).

Lacticaseibacillus salsurivasis sp. nov. and Companilactobacillus muriivasis sp. nov., Isolated from Traditional Chinese Pickle.

Three Gram-stain-positive bacterial strains were isolated from traditional Chinese pickle and characterized using a polyphasic taxonomic approach. Results of 16S rRNA gene sequence analysis indicated that strain 74-4T was most closely related to the type strains of Lacticaseibacillus suibinensis and Lacticaseibacillus suilingensis, having 99.9% and 100% 16S rRNA gene sequence similarities, respectively, and that strains 419-1.2T and 262-4 were most closely related to the type strains of Companilactobacillus heilongjiangensis, Companilactobacillus nantensis, Companilactobacillus huachuanensis, and Companilactobacillus nuruki, having 98.5-99.7% 16S rRNA gene sequence similarities. The phylogenomic trees indicated that strain 74-4T was related to the type strains of L. suibinensis and L. suilingensis, and that strains 419-1.2T and 262-4 were related to the type strains of C. heilongjiangensis, C. nantensis, C. huachuanensis, and Companilactobacillus zhachilii. The ANI and dDDH values between strain 74-4T and type strains of phylogenetically related species were less than 92.7% and 49.9%, respectively. The ANI and dDDH values between strains 419-1.2T and 262-4 and type strains of phylogenetically related species were less than 93.4% and 51.7%, respectively. Based upon the data of polyphasic characterization obtained in the present study, two novel species, Lacticaseibacillus salsurivasis sp. nov. and Companilactobacillus muriivasis sp. nov., are proposed and the type strains are 74-4T (= JCM 35890T = CCTCC AB 2022414T) and 419-1.2T (= JCM 35891T = CCTCC AB 2022413T), respectively.

Lacticaseibacillus jixiensis sp. nov., Isolated from Traditional Chinese Pickle.

A novel lactic acid bacterial strain (designated N163-3-2T), isolated from traditional Chinese pickle ('Suan cai'), was characterized using a polyphasic approach. Strain N163-3-2T was most closely related to the type strains of Lacticaseibacillus baoqingensis, Lacticaseibacillus manihotivorans, and Lacticaseibacillus porcinae, having 97.9-98.4% 16S rRNA gene, 82.0-85.1% pheS, 87.5-87.8% rpoA, and 85.8-86.7% concatenated pheS and rpoA sequence similarities. Strain N163-3-2T had 74.4-81.7% ANI, 22.6-23.9% dDDH, and 74.0-75.1% AAI values with L. baoqingensis 47-3T, L. manihotivorans DSM 13343T and L. porcinae JCM 19617T, less than the threshold for species demarcation (95-96%, 70% and 95-96%, respectively), indicating that strain N163-3-2T represented a novel species of the genus Lacticaseibacillus. Based upon the data obtained in the present study, a novel species, Lacticaseibacillus jixiensis sp. nov., is proposed, and the type strain is N163-3-2T (= CCTCC AB 2024125T = JCM 36999T).

Lacticaseibacillus paracsei HY7207 Alleviates Hepatic Steatosis, Inflammation, and Liver Fibrosis in Mice with Non-Alcoholic Fatty Liver Disease.

Non-alcoholic fatty acid disease (NAFLD) is caused by a build-up of fat in the liver, inducing local inflammation and fibrosis. We evaluated the effects of probiotic lactic acid-generating bacteria (LAB) derived from a traditional fermented beverage in a mouse model of NAFLD. The LAB isolated from this traditional Korean beverage were screened using the human hepatic cell line HepG2, and Lactocaseibacillus paracasei HY7207 (HY7207), which was the most effective inhibitor of fat accumulation, was selected for further study. HY7207 showed stable productivity in industrial-scale culture. Whole-genome sequencing of HY7207 revealed that the genome was 2.88 Mbp long, with 46.43% GC contents and 2778 predicted protein-coding DNA sequences (CDSs). HY7207 reduced the expression of lipogenesis and hepatic apoptosis-related genes in HepG2 cells treated with palmitic acid. Furthermore, the administration of 109 CFU/kg/day of HY7207 for 8 weeks to mice fed an NAFLD-inducing diet improved their physiologic and serum biochemical parameters and ameliorated their hepatic steatosis. In addition, HY7207 reduced the hepatic expression of genes important for lipogenesis (Srebp1c, Fasn, C/ebpa, Pparg, and Acaca), inflammation (Tnf, Il1b, and Ccl2), and fibrosis (Col1a1, Tgfb1, and Timp1). Finally, HY7207 affected the expression of the apoptosis-related genes Bax (encoding Bcl2 associated X, an apoptosis regulator) and Bcl2 (encoding B-cell lymphoma protein 2) in the liver. These data suggest that HY7207 consumption ameliorates NAFLD in mice through effects on liver steatosis, inflammation, fibrosis, and hepatic apoptosis. Thus, L. paracasei HY7207 may be suitable for use as a functional food supplement for patients with NAFLD.

An underlying mechanism for MleR activating the malolactic enzyme pathway to enhance acid tolerance in Lacticaseibacillus paracasei L9.

Tolerance to acid stress is a crucial property of probiotics against gastric acids. The malolactic enzyme pathway is one of the most important acid resistance systems in lactic acid bacteria. It has been reported that the malolactic enzyme pathway was regulated by the transcriptional regulator, MleR. However, regulatory mechanisms underlying malolactic enzyme pathway to cope with acid stress remain unknown. In this study, the acid tolerance ability of the ΔmleR deletion strain was significantly lower than that of the wild-type strain, and the complementation of the mleR gene into the ΔmleR strain restored the acid tolerance of the ΔmleR strain, indicating that MleR was involved in acid tolerance response of Lacticaseibacillus paracasei L9. Real-time quantitative PCR and transcriptional fusion experiments confirmed MleR-activated transcription of the mleST gene cluster. Furthermore, MleR was confirmed to directly bind to the promoter region of the mleST operon using ChIP assays and EMSAs. The transcription start site G of the mleST operon was located at position -198 relative to the start codon of the mleS gene. The region from -80 to -61 upstream of the transcription start site was determined to be essential for MleR binding. Moreover, L-malic acid acted as an effector for MleR to activate the transcription of the mleST operon in a dose-dependent manner. These results revealed the regulatory mechanism behind MleR-mediated activation of the malolactic enzyme pathway to enhance acid tolerance in Lc. paracasei L9. IMPORTANCE Lacticaseibacillus paracasei is extensively used as probiotics in human health and fermented dairy production. Following consumption, Lc. paracasei is exposed to a variety of physico-chemical stresses, such as low pH in the stomach and bile salts in the intestines. The high acidity of the stomach severely inhibits bacterial metabolism and growth. Therefore, the acid tolerance response is critical for Lc. paracasei to survive. It has been reported that the malolactic enzyme (MLE) pathway plays an important role for LAB to resist acid stress. However, the regulatory mechanism has not yet been investigated. In this study, we determined that the LysR-type regulator MleR positively regulated the MLE pathway to enhance acid tolerance by binding -80 to -61 upstream of the transcription start site of the mleST operon. Further, L-malic acid acts as a co-inducer for MleR transcriptional regulation. Our study provides novel insights into acid tolerance mechanisms in LAB.

Detection of Glycolytically Active Lacticaseibacillus paracasei Strain Shirota by Flow Cytometry Targeting the Efflux Activity of Fluorescent Dye: a Potential Tool for Quality Assessment of Probiotic Cells in Milk Products.

The rapid and accurate detection of viable probiotic cells in dairy products is important for assessing product quality in manufacturing. Flow cytometry is widely used for the rapid analysis of bacterial cells. However, further investigation is needed into the optimum property to use it for assessing cell viability. Here, we proposed using the efflux activity of a fluorescent dye, carboxyfluorescein (CF), as an indicator of cell viability. CF is generated from 5(6)-carboxyfluorescein diacetate as a result of cleavage by intracellular esterase. It generally accumulates in the cell, but certain bacterial species are known to extrude it. We found here that the probiotic strain Lacticaseibacillus paracasei strain Shirota (LcS) also extruded CF in the presence of energy sources, such as glucose. To investigate the mechanism of its CF-efflux activity, we screened CF-efflux-negative mutants from a random mutagenesis LcS library and examined the whole genome for genes responsible for CF efflux. We identified a base substitution in the pfkA gene in the glycolytic pathway, and we demonstrated that intact pfkA was essential for CF efflux, indicating that CF-efflux-positive cells must have uncompromised glycolytic activity. We also confirmed that there was a good correlation between the rate of CF-efflux-positive cells and that of colony-forming cells of LcS in a fermented milk product, whereas other properties, such as esterase activity and cell membrane integrity, lost their correlation with the colony-forming activity after long storage. We propose that CF-efflux activity could be an appropriate indicator of cell viability in certain probiotic strains. IMPORTANCE To our knowledge, this is the first report to demonstrate that CF efflux requires uncompromised glycolytic activity in certain lactic acid bacteria. Compared with the cell properties currently widely used for cell viability assessment, such as intracellular esterase activity and membrane integrity, CF-efflux activity enables the accurate detection of culturable cells, especially in products stored for long periods at cold temperatures. These results indicate strongly that CF-efflux activity can be an adequate cell-viability indicator and that flow cytometric quantification could be an alternative to conventional CFU counting. Our findings should be especially informative for dairy/probiotic product manufacturing.

Heat-killed Lacticaseibacillus paracasei GMNL-653 ameliorates human scalp health by regulating scalp microbiome.

BACKGROUND: The equilibrium of the scalp microbiome is important for maintaining healthy scalp conditions, including sebum secretion, dandruff, and hair growth. Many different strategies to improve scalp health have been reported; however, the effect of postbiotics, such as heat-killed probiotics, on scalp health remains unclear. We examined the beneficial effects of heat-killed probiotics consisting of Lacticaseibacillus paracasei, GMNL-653, on scalp health. RESULTS: Heat-killed GMNL-653 could co-aggregate with scalp commensal fungi, Malassezia furfur, in vitro, and the GMNL-653-derived lipoteichoic acid inhibited the biofilm formation of M. furfur on Hs68 fibroblast cells. The mRNA of hair follicle growth factors, including insulin-like growth factor-1 receptor (IGF-1R), vascular endothelial growth factor, IGF-1, and keratinocyte growth factor was up-regulated in skin-related human cell lines Hs68 and HaCaT after treatment with heat-killed GMNL-653. For clinical observations, we recruited 22 volunteer participants to use the shampoo containing the heat-killed GMNL-653 for 5 months and subsequently measured their scalp conditions, including sebum secretion, dandruff formation, and hair growth. We applied polymerase chain reaction (PCR) to detect the scalp microbiota of M. restricta, M. globosa, Cutibacterium acnes, and Staphylococcus epidermidis. A decrease in dandruff and oil secretion and an increase in hair growth in the human scalp were observed after the use of heat-killed GMNL-653-containing shampoo. The increased abundance of M. globosa and the decreased abundance of M. restricta and C. acnes were also observed. We further found that accumulated L. paracasei abundance was positively correlated with M. globosa abundance and negatively correlated with C. acnes abundance. S. epidermidis and C. acnes abundance was negatively correlated with M. globosa abundance and positively correlated with M. restricta. Meanwhile, M. globosa and M. restricta abundances were negatively associated with each other. C. acnes and S. epidermidis abundances were statistically positively correlated with sebum secretion and dandruff, respectively, in our shampoo clinical trial. CONCLUSION: Our study provides a new strategy for human scalp health care using the heat-killed probiotics GMNL-653-containing shampoo. The mechanism may be correlated with the microbiota shift.

Antibacterial and antibiofilm potential of Lacticaseibacillus rhamnosus YT and its cell-surface extract.

BACKGROUND: Foodborne pathogens and spoilage bacteria survived in the biofilm pose a serious threat to food safety and human health. It is urgent to find safe and effective methods to control the planktonic bacteria as well as the biofilm formation. Substances with antibacterial and antibiofilm activity found in lactic acid bacteria were mainly metabolites secreted in the cell-free supernatant. Previously, Lacticaseibacillus rhamnosus YT was isolated because its cell pellets displayed distinguished antibacterial activity under neutral conditions. This study aimed to investigate the antibacterial and antibiofilm properties of the L. rhamnosus YT cells and its crude cell-surface extract. RESULTS: The antibacterial activity of the L. rhamnosus YT cells constantly increased with cells growth and reached the peak value after the cells grew into stationary phase. After cocultivation with the L. rhamnosus YT cells, the biofilm formation of B. subtilis and S. enterica was reduced. The antibacterial activity of the L. rhamnosus YT cells was varied along with various culture conditions (carbon sources, nitrogen sources, medium pH and cultural temperatures) and the antibacterial intensity (antibacterial activity per cell) was disproportional to the biomass. Furthermore, the cell-surface extract was isolated and displayed broad antimicrobial spectrum with a bacteriostatic mode of action. The antibiofilm activity of the extract was concentration-dependent. In addition, the extract was stable to physicochemical treatments (heat, pH and protease). The extract performed favorable emulsifying property which could reduce the water surface tension from 72.708 mN/m to 51.011 mN/m and the critical micelle concentration (CMC) value was 6.88 mg/mL. Besides, the extract was also able to emulsify hydrocarbon substrates with the emulsification, index (E24) ranged from 38.55% (for n-hexane) to 53.78% (for xylene). The E24 for xylene/extract emulsion was merely decreased by 5.77% after standing for 120 h. The main components of the extract were polysaccharide (684.63 µg/mL) and protein (120.79 µg/mL). CONCLUSION: The properties of the extract indicated that it might be a kind of biosurfactant. These data suggested that L. rhamnosus YT and the cell-surface extract could be used as an alternative antimicrobial and antibiofilm agent against foodborne pathogens and spoilage bacteria in food industry.

Lacticaseibacillus casei T1 attenuates Helicobacter pylori-induced inflammation and gut microbiota disorders in mice.

Probiotics are defined as live microbial food elements that are beneficial to human health. Lacticaseibacillus casei T1 was considered to have potential as a bioactive ingredient in functional foods, which was isolated from kurut. Previous research by our group proved that L. casei T1 could prevent inflammatory responses caused by Helicobacter pylori. This study aimed to investigate whether treatment with L. casei T1 resulted in a suppressive effect on H. pylori-induced oxidative stress and inflammatory responses. The results showed that treatment with L. casei T1 could relieve H. pylori-induced overexpression of inflammatory cytokines in GES-1 cells. Experiments in animals suggested that taking long-term L. casei T1 could reduce oxidative stress and inflammatory cytokines and improve H. pylori-induced gastric mucosal damage. Furthermore, taking L. casei T1 could increase the relative abundance of beneficial intestinal bacterium (Lachnospiraceae and Odoribacter) of H. pylori-infected mice and help in maintaining the balance of intestinal microflora.Collectively, L. casei T1 had certain degrees of therapeutic effect against H. pylori. In the future, it combined with antibiotics for H. pylori eradication deserves further study.

Assessing the protection mechanisms on Enterobacter aerogenes ATCC 13048 by potentially probiotic strain Lacticaseibacillus casei XN18: An experimental and modeling study.

In this study, Lacticaseibacillus casei XN18 had a remarkable resistant to simulated gastrointestinal conditions, hydrophobicity (38.60%), auto-aggregation (29.80%), co-aggregation (21.10%), adhesion (9.50%), anti-adhesion (24.40-36.90%), antioxidant activity (46.47%), cholesterol assimilation (41.10%), and antimicrobial effect on some pathogenic microorganisms. The modified double layer method, and Enterobacter aerogenes (inhibition zone (IZ) = 9.10 mm) and Listeria monocytogenes (IZ = 14.60 mm) were the most sensitive and resistant pathogens to the probiotic strain. The Lb. casei was sensitive to ciprofloxacin (IZ = 23 mm) and nitrofurantoin (IZ = 25.10 mm), semi-sensitive to imipenem (IZ = 18.80 mm), erythromycin (IZ = 16.90 mm), and chloramphenicol (IZ = 17.90 mm), and resistant to ampicillin (IZ = 9.60 mm) and nalidixic acid (IZ = 9.90 mm). The Lb. casei showed no haemolytic and DNase properties, and it could therefore be used for health-promoting purposes. In the next section, multilayer perceptron (MLP) neural network (NN) and gaussian process regression (GPR) models with k-fold cross validation method were used for predicting the rate of probiotic viability based on three levels of pH and time. The results showed that GPR has the lowest error. The mean absolute percentage error (MAPE), root mean absolute error (RMSE) and coefficient of determination (R2) for GPR and MLP models were 1.49 ± 0.40, 0.21 ± 0.03, 0.98 ± 0.05 and 6.66 ± 0.98, 0.83 ± 0.23 0.82 ± 0.09, respectively. So, the GPR model can be reliably used as a useful method to predict the probiotic viability in similar cases.

Lacticaseibacillus paracasei fermentation broth identified peptide, Y2Fr, and its antibacterial activity on Vibrio parahaemolyticus.

Although Vibrio parahaemolyticus infections cause severe diseases of large yellow croaker (Larimichthys crocea), using antibiotics and other chemical agents to treat these infections could result in antimicrobial resistance, environmental pollution, and other associated problems. This study identified seven peptides from Lacticaseibacillus paracasei fermentation broth using ultra-high-performance liquid chromatography-mass spectrometry and screened antimicrobial peptide Y2Fr (VEIKNGLLKLNGKPLLIR) through its net charge, hydrophobicity and predicted secondary structure. Antibacterial activity analysis revealed that Y2Fr had a minimum inhibitory concentration (MIC) of 125 µg/mL, minimum bactericidal concentration (MBC) of 250 µg/mL against V. parahaemolyticus and a time-kill of 3 h. In a bacterial membrane environment, the secondary structure of peptide Y2Fr changed from a random coil to a ß-sheet to enhance its membrane permeability and binding to bacteria DNA to exert its antibacterial effect. Further molecular docking analysis revealed that peptide Y2Fr could bind to the membrane protein KKI11460.1 and DNA polymerase A0A0L8TVA4 of V. parahaemolyticus through hydrogen bonds. Meanwhile, treatment of Y2Fr with mammalian red blood cells and plasma revealed that it was noncytotoxic, nonhemolytic, and stable under physiological conditions. Thus, peptide Y2Fr has great potential use in treating and preventing infections caused by V. parahaemolyticus or similar bacteria in aquatic animals.

Roles of luxS in regulation of probiotic characteristics and inhibition of pathogens in Lacticaseibacillus paracasei S-NB.

Lactic acid bacteria (LAB) have excellent tolerance to the gastrointestinal environment and high adhesion ability to intestinal epithelial cells, which could be closely related to the LuxS/AI-2 Quorum sensing (QS) system. Here, the crucial enzymes involved in the synthesis of AI-2 was analyzed in Lacticaseibacillus paracasei S-NB, and the luxS deletion mutant was constructed by homologous recombination based on the Cre-lox system. Afterwards, the effect of luxS gene on the probiotic activities in L. paracasei S-NB was investigated. Notably, the tolerance of simulated gastrointestinal digestion, AI-2 production, ability of auto-aggregation and biofilm formation significantly decreased (p < 0.05 for all) in the S-NB△luxS mutant. Compared to the wild-type S-NB, the degree of reduction in the relative transcriptional level of the biofilm -related genes in Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923 was diminished when co-cultured with S-NB△luxS. Furthermore, the inhibitory effect of S-NB△luxS on the adhesion (competition, exclusion and displacement) of E. coli ATCC 25922 and S. aureus ATCC 25923 to Caco-2 cells markedly decreased. Therefore, comprehensive analysis of the role by luxS provides an insight into the LuxS/AI-2 QS system of L. paracasei S-NB in the regulation of strain characteristics and inhibition of pathogens.

Lacticaseibacillus parakribbianus sp. nov., isolated from a pig farm faeces dump.

A lactic acid bacterium isolated from pig faeces was characterized using a polyphasic approach. The strain was Gram-stain-positive, rod-shaped, and facultative anaerobic. Phylogenetic analysis of the 16S rRNA gene sequence indicated that the isolate belonged to the genus Lacticaseibacillus. The multi-locus sequence tree revealed that the strain formed a sub-cluster adjacent to Lacticaseibacillus kribbianus. The main fatty acids were C16 : 0 and C18 : 1ω9c. The average nucleotide identity value, average amino acid identity, and genome-to-genome distance for YH-lacS6T and its most closely related strain, L. kribbianus, were 85.4, 85.2 and 29.2 %, respectively. The G+C content of the genomic DNA was 61.6 mol%. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, aminophospholipids and phospholipids. The cell-wall peptidoglycan did not contain meso-diaminopimelic acid. Thus, YH-lacS6T (=KCTC 21186T=JCM 34954T) represents a novel species. The name Lacticaseibacillus parakribbianus sp. nov. is proposed.

The extracellular polysaccharide inhibit porcine epidemic diarrhea virus with extract and gene editing Lacticaseibacillus.

Lacticaseibacillus is one of the predominant microorganisms in gut from human and animal, and the lacticaseibacillus have effective applications against the viral diarrhea of piglets in the farm. However, the function and the concrete cell single pathways of the active ingredient from lacticaseibacillus was not clear within anti-infection in the postbiotics research. Here, we compared the biological function of extracellular polysaccharides (EPS) purified from lacticaseibacillus casei (L. casei) and gene editing lacticaseibacillus casei with the CRISPER-Cas9 technology, which were with the ability of antioxidation and anti-inflammation, and the EPS could also inhibit the ROS production within the Porcine Small Intestinal Epithelial Cells-J2 (IPEC-J2). Interestingly, we found that both of EPS and genome editing lacticaseibacillus casei could specifically target the IFN-λ expression in the IPEC-J2, which was beneficial against the PEDV infection in the virus replication and production with the qRT-PCR and indirect immunofluorescence methods. Finally, the STAT3 cell single pathway was stimulated to transcribe IFN-λ with the EPS to elucidate the detailed mechanism of activating type III IFN signals receptor of IL-10R2, which play the function between anti-inflammation and anti-virus in the PEDV infection. Taken together, our research linked a postbiotics of EPS with the antiviral infection of PEDV, which suggest that the lacticaseibacillus itself still have displayed the potential immunomodulatory activities, and highlight the immunomodulatory potential of EPS-producing microbes.

Lacticaseibacillus rhamnosus GG enhances fin regeneration under oxytetracycline exposure via activating Wnt signaling and modulating gut microbiota.

Zebrafish possesses robust caudal fin regeneration which depends on multiple factors to maintain body integrity. However, it is uncertain whether the caudal fin regeneration is related to gut microbiota. Here, we investigated the effect of Lacticaseibacillus rhamnosus GG (LGG) on the regeneration of caudal fin under oxytetracycline (OTC) exposure. The results demonstrated that 1000 µg/L OTC exposure for 4 days decreased reactive oxygen species (ROS) production at 1 and 3 h post amputation (hpa), increased neutrophil recruitment at 6 hpa, enhanced the number of apoptotic cells at 1, 3, 6 and 12 hpa and inhibited Wnt signaling pathway at 48 hpa in wound site. Furthermore, OTC exposure caused dysbacteriosis by elevating level of Proteobacteria and decreasing the abundance of Firmicutes, particularly Lacticaseibacillus, thereby negatively impacting wound healing and repair. Additionally, the administration of 106 CFU/mL of LGG for 48 h could improve intestinal environment through increasing the colonization rate of LGG in OTC-treated larvae intestines. The regenerative process restored by LGG was accompanied with increased ROS production at 1, 3 and 6 hpa, inhibited neutrophil recruitment at 6 hpa, decreased the number of apoptotic cells at 1 hpa, and activated Wnt signaling pathway at 48 hpa in OTC-treated fish. LGG is a promising bacterium for restoring fin regeneration and provides new insights regarding the correlation among the gut microbiota and fin regeneration.

Lacticaseibacillus casei CNRZ1874 supplementation promotes M1 alveolar macrophage activation and attenuates Mycoplasma pneumoniae pneumonia.

AIMS: To evaluate the protective effect of intestinal supplementation with Lacticaseibacillus casei CNRZ1874 on the inflammatory response induced by Mycoplasma pneumoniae in C57BL/6 J mice, and provide a potential strategy for alleviating M. pneumoniae pneumonia. METHODS AND RESULTS: C57BL/6 J mice were gavaged with L. casei CNRZ1874 or PBS for 7 consecutive days, and then infected with M. pneumoniae on day 8. Treatment with L. casei CNRZ1874 significantly reduced M. pneumoniae loads in the lungs and alleviated the lung inflammation on day 3 and 10 after pathogen infection. Importantly, oral administration with L. casei CNRZ1874 promoted M1 alveolar macrophages activation as evidenced by increased expression of iNOS, TNF-α, and CXCL1, while inhibited M2 alveolar macrophages activation as the expression of Arg1 and Chi3l3 were significantly decreased. In consistent with the M1 alveolar macrophages activation and enhanced mycoplasma clearance, the level of TNF-α was increased while the level of IL-4 was decreased in lung tissue from the L. casei CNRZ1874 group compared with the control group. However, oral administration with L. casei CNRZ1874 may not influence adaptive immunity induced by M. pneumoniae as evaluated by M. pneumoniae specific antibodies and T cells responses in spleen. CONCLUSIONS: Intestinal supplementation with L. casei CNRZ1874 can promote M1 alveolar macrophages activation, which contributes to the clearance of M. pneumoniae and attenuation of M.pneumoniae pneumonia.

Protective effects of Lacticaseibacillus rhamnosus on isoprenaline-induced myocardial infarction in rats.

AIMS: Myocardial infarction (MI) is among the main public health problems in the world. This atherosclerotic cardiovascular disease (ASCVD), which seriously endangers human health, progresses to cause heart failure and myocardial fibrosis with a poor prognosis. The gut microbiota plays an important role in health and disease, including obesity and ASCVD. In this study, the protective effect of Lacticaseibacillus rhamnosus GG, known for its anti-inflammatory and antioxidant effects, on isoprenaline (ISO)-induced MI in rats was investigated. METHODS AND RESULTS: Rats were divided into four groups of seven rats in each group as control, ISO, L. rhamnosus, and ISO + L. rhamnosus.The ISO application was made by subcutaneous injection to the rats on the last two days (days 27th and 28th) of the 28-day substance administration. The rats were anesthetized 24 hours after the application of ISO, and blood samples were collected after electrocardiogram (ECG) recordings. To determine myocardial damage and protective effects of L. rhamnosus, serum creatine kinase-MB, cardiac troponin-I, tumor necrosis factor-alpha, interleukin-10, and C-reactive protein (CRP) levels were examined. In addition, ECG recordings were evaluated. While L. rhamnosus had a decreasing effect on cardiac troponin-I, creatine kinase-MB, CRP, and tumor necrosis factor-alpha levels, which increased due to ISO, it had an increasing effect on interleukin-10 levels. Similarly, it decreased the ST-segment elevation caused by ISO while increasing the reduced R wave amplitude.

Lacticaseibacillus rhamnosus HA-114 improves eating behaviors and mood-related factors in adults with overweight during weight loss: a randomized controlled trial.

Background: Gut microbiota has emerged as a modifiable factor influencing obesity and metabolic diseases. Interventions targeting this microbial community could attenuate biological and psychological comorbidities of excess weight. Objective: Our aim was to determine if Lacticaseibacillus rhamnosus HA-114 supplementation accentuated beneficial impact of weight loss on metabolic and cognitive health. Methods: This 12-week randomized, double-blind, placebo-controlled trial assessed biological markers of energy metabolism, eating behaviors and mood-related factors in 152 adults with overweight receiving L. rhamnosus HA-114 supplementation or placebo, that were also on a dietary intervention inducing a controlled weight loss. Results: Although probiotic supplementation did not potentiate the reduction in body weight or fat mass, a significant decrease in plasma insulin, HOMA-IR, LDL-cholesterol and triglycerides was observed in the probiotic-supplemented group only. With respect to eating behaviors and mood-related factors, beneficial effects were either observed only in the group receiving probiotic supplementation or were significantly greater in this group, including decrease in binge eating tendencies, disinhibition and food-cravings. Conclusion: This study demonstrates the clinical relevance of probiotic supplementation to induce beneficial metabolic and psychological outcomes in individuals with overweight undergoing weight loss.Trial registration: ClinicalTrials.gov identifier: NCT02962583.