Lactobacillus delbrueckii subsp. lactis (strain CIDCA 133) stimulates murine macrophages infected with Citrobacter rodentium

Synergistic synbiotic containing fructooligosaccharides and Lactobacillus delbrueckii CIDCA 133 alleviates chemotherapy-induced intestinal mucositis in mice

Intestinal mucositis is a commonly reported side effect in oncology patients undergoing chemotherapy and radiotherapy. Probiotics, prebiotics, and synbiotics have been investigated as alternative therapeutic approaches against intestinal mucositis due to their well-known anti-inflammatory properties and health benefits to the host. Previous studies showed that the potential probiotic Lactobacillus delbrueckii CIDCA 133 and the prebiotic Fructooligosaccharides (FOS) alleviated the 5-Fluorouracil (5-FU) chemotherapy-induced intestinal mucosa damage. Based on these previous beneficial effects, this work evaluated the anti-inflammatory property of the synbiotic formulation containing L. delbrueckii CIDCA 133 and FOS in mice intestinal mucosa inflammation induced by 5-FU. This work showed that the synbiotic formulation was able to modulate inflammatory parameters, including reduction of cellular inflammatory infiltration, gene expression downregulation of Tlr2, Nfkb1, and Tnf, and upregulation of the immunoregulatory Il10 cytokine, thus protecting the intestinal mucosa from epithelial damage caused by the 5-FU. The synbiotic also improved the epithelial barrier function by upregulating mRNA transcript levels of the short chain fatty acid (SCFA)-associated GPR43 receptor and the occludin tight junction protein, with the subsequent reduction of paracellular intestinal permeability. The data obtained showed that this synbiotic formulation could be a promising adjuvant treatment to be explored against inflammatory damage caused by 5-FU chemotherapy.

Genomic Characterization of Lactobacillus delbrueckii Strains with Probiotics Properties

Probiotics are health-beneficial microorganisms with mainly immunomodulatory and anti-inflammatory properties. Lactobacillus delbrueckii species is a common bacteria used in the dairy industry, and their benefits to hosting health have been reported. This study analyzed the core genome of nine strains of L. delbrueckii species with documented probiotic properties, focusing on genes related to their host health benefits. For this, a combined methodology including several software and databases (BPGA, SPAAN, BAGEL4, BioCyc, KEEG, and InterSPPI) was used to predict the most important characteristics related to L. delbrueckii strains probiose. Comparative genomics analyses revealed that L. delbrueckii probiotic strains shared essential genes related to acid and bile stress response and antimicrobial activity. Other standard features shared by these strains are surface layer proteins and extracellular proteins-encoding genes, with high adhesion profiles that interacted with human proteins of the inflammatory signaling pathways (TLR2/4-MAPK, TLR2/4-NF-κB, and NOD-like receptors). Among these, the PrtB serine protease appears to be a strong candidate responsible for the anti-inflammatory properties reported for these strains. Furthermore, genes with high proteolytic and metabolic activity able to produce beneficial metabolites, such as acetate, bioactive peptides, and B-complex vitamins were also identified. These findings suggest that these proteins can be essential in biological mechanisms related to probiotics’ beneficial effects of these strains in the host.

Lactobacillus delbrueckii CIDCA 133 Ameliorates Chemotherapy-Induced Mucositis by Modulating Epithelial Barrier and TLR2/4/Myd88/NF-κB Signaling Pathway

Intestinal mucositis promoted by the use of anticancer drugs is characterized by ulcerative inflammation of the intestinal mucosa, a debilitating side effect in cancer patients undergoing treatment. Probiotics are a potential therapeutic option to alleviate intestinal mucositis due to their effects on epithelial barrier integrity and anti-inflammatory modulation. This study investigated the health-promoting impact of Lactobacillus delbrueckii CIDCA 133 in modulating inflammatory and epithelial barrier markers to protect the intestinal mucosa from 5-fluorouracil-induced epithelial damage. L. delbrueckii CIDCA 133 consumption ameliorated small intestine shortening, inflammatory cell infiltration, intestinal permeability, villus atrophy, and goblet cell count, improving the intestinal mucosa architecture and its function in treated mice. Upregulation of Muc2, Cldn1, Hp, F11r, and Il10, and downregulation of markers involved in NF-κB signaling pathway activation (Tlr2, Tlr4, Nfkb1, Il6, and Il1b) were observed at the mRNA level. This work suggests a beneficial role of L. delbrueckii strain CIDCA 133 on intestinal damage induced by 5-FU chemotherapy through modulation of inflammatory pathways and improvement of epithelial barrier function.

Safety Evaluation of Lactobacillus delbrueckii subsp. lactis CIDCA 133: a Health-Promoting Bacteria

Lactobacillus delbrueckii subsp. lactis CIDCA is a new potential probiotic strain whose molecular basis attributed to the host's benefit has been reported. This study investigated the safety aspects of Lactobacillus delbrueckii subsp. lactis CIDCA 133 based on whole-genome sequence and phenotypic analysis to avoid future questions about the harmful effects of this strain consumption. Genomic analysis showed that L. delbrueckii subsp. lactis CIDCA 133 harbors virulence, harmful metabolites, and antimicrobial resistance-associated genes. However, none of these genetic elements is flanked or located within prophage regions and plasmid sequence. At a phenotypic level, it was observed L. delbrueckii subsp. lactis CIDCA 133 antimicrobial resistance to aminoglycosides streptomycin and gentamicin antibiotics, but no hemolytic and mucin degradation activity was exhibited by strain. Furthermore, no adverse effects were observed regarding mice clinical and histopathological analysis after the strain consumption (5 × 10⁷ CFU/mL). Overall, these findings reveal the safety of Lactobacillus delbrueckii subsp. lactis CIDCA 133 for consumption and future probiotic applications.

Probiogenomics of Lactobacillus delbrueckii subsp. lactis CIDCA 133: In Silico, In Vitro, and In Vivo Approaches

Lactobacillus delbrueckii subsp. lactis CIDCA 133 (CIDCA 133) has been reported as a potential probiotic strain, presenting immunomodulatory properties. This study investigated the possible genes and molecular mechanism involved with a probiotic profile of CIDCA 133 through a genomic approach associated with in vitro and in vivo analysis. Genomic analysis corroborates the species identification carried out by the classical microbiological method. Phenotypic assays demonstrated that the CIDCA 133 strain could survive acidic, osmotic, and thermic stresses. In addition, this strain shows antibacterial activity against Salmonella Typhimurium and presents immunostimulatory properties capable of upregulating anti-inflammatory cytokines Il10 and Tgfb1 gene expression through inhibition of Nfkb1 gene expression. These reported effects can be associated with secreted, membrane/exposed to the surface and cytoplasmic proteins, and bacteriocins-encoding genes predicted in silico. Furthermore, our results showed the genes and the possible mechanisms used by CIDCA 133 to produce their beneficial host effects and highlight its use as a probiotic microorganism.

Intake of Lactobacillus delbrueckii (pExu:hsp65) Prevents the Inflammation and the Disorganization of the Intestinal Mucosa in a Mouse Model of Mucositis

5-Fluorouracil (5-FU) is an antineoplastic drug that causes, as a side effect, intestinal mucositis, acute inflammation in the small bowel. The Heat Shock Protein (Hsp) are highly expressed in inflammatory conditions, developing an important role in immune modulation. Thus, they are potential candidates for the treatment of inflammatory diseases. In the mucositis mouse model, the present study aimed to evaluate the beneficial effect of oral administration of milk fermented by Lactobacillus delbrueckii CIDCA 133 (pExu:hsp65), a recombinant strain. This approach showed increased levels of sIgA in the intestinal fluid, reducing inflammatory infiltrate and intestinal permeability. Additionally, the histological score was improved. Protection was associated with a reduction in the gene expression of pro-inflammatory cytokines such as Tnf, Il6, Il12, and Il1b, and an increase in Il10, Muc2, and claudin 1 (Cldn1) and 2 (Cldn2) gene expression in ileum tissue. These findings are corroborated with the increased number of goblet cells, the electronic microscopy images, and the reduction of intestinal permeability. The administration of milk fermented by this recombinant probiotic strain was also able to reverse the high levels of gene expression of Tlrs caused by the 5-FU. Thus, the rCIDCA 133:Hsp65 strain was revealed to be a promising preventive strategy for small bowel inflammation.

Isolation, expression, and biochemical characterization: nitrite reductase from Bacillus cereus LJ01

Biological remediation of toxic oxygen-containing anions such as nitrate that are common in the environment is of great significance. Therefore, it is necessary to understand the specific role of nitrate and nitrite reductase in the bioremediation process. Bacillus cereus LJ01, which was isolated from traditional Chinese soybean paste, effectively degraded nitrite (such as NaNO₂) at 0–15 mmol L⁻¹ in LB medium. Moreover, the nitrite-degrading active substance (ASDN) was isolated and purified from B. cereus LJ01. The nitrite-degrading activity of nitrite reductase (named LJ01-NiR) was 4004.89 U mg⁻¹. The gene encoding the assimilation of nitrite reductase in B. cereus LJ01 was cloned and overexpressed in E. coli. The purified recombinant LJ01-NiR has a wide range of activities under temperature (20–60 °C), pH (6.5–8.0) and metal ions (Fe³⁺, Fe²⁺, Cu²⁺, Mn²⁺, and Al³⁺). Kinetic parameters of LJ01-NiR, including the values of K_m and V_max were 1.38 mM and 2.00 μmol g⁻¹ min⁻¹, respectively. The results showed that LJ01-NiR could degrade nitrite with or without an electron donor. In addition, sequence analysis revealed that LJ01-NiR was a ferredoxin-dependent nitrite reductase given the presence of conserved [Fe4–S4] cluster and heme-binding domain. The nitrite ion binds to the LJ01-NiR active site by forming three hydrogen bonds with the residues ASN72, ALA133 and ASN140. Due to its high nitrite-degrading activity, LJ01-NiR could potentially be used for environmental pollution treatment.

Biological remediation of toxic oxygen-containing anions such as nitrite in the environment is of great significance. Bacillus cereus LJ01 showed the activity of degradation for nitrite. the enzyme NiR from LJ01 can degrade the nitrite in vitro.

Differential Stability of Aurein 1.2 Pores in Model Membranes of Two Probiotic Strains

Aurein 1.2 is an antimicrobial peptide from the skin secretion of an Australian frog. In the previous experimental work, we reported a differential action of aurein 1.2 on two probiotic strains Lactobacillus delbrueckii subsp. bulgaricus (CIDCA 331) and Lactobacillus delbrueckii subsp. lactis (CIDCA 133). The differences found were attributed to the bilayer compositions. Cell cultures and CIDCA 331-derived liposomes showed higher susceptibility than the ones derived from the CIDCA 133 strain, leading to content leakage and structural disruption. Here, we used molecular dynamics simulations to explore these systems at the atomistic level. We hypothesize that if the antimicrobial peptides organized themselves to form a pore, it will be more stable in membranes that emulate the CIDCA 331 strain than in those of the CIDCA 133 strain. To test this hypothesis, we simulated preassembled aurein 1.2 pores embedded into bilayer models that emulate the two probiotic strains. It was found that the general behavior of the systems depends on the composition of the membrane rather than the preassemble system characteristics. Overall, it was observed that aurein 1.2 pores are more stable in the CIDCA 331 model membranes. This fact coincides with the high susceptibility of this strain against antimicrobial peptide. In contrast, in the case of the CIDCA 133 model membranes, peptides migrate to the water-lipid interphase, the pore shrinks, and the transport of water through the pore is reduced. The tendency of glycolipids to make hydrogen bonds with peptides destabilizes the pore structures. This feature is observed to a lesser extent in CIDCA 331 due to the presence of anionic lipids. Glycolipid transverse diffusion (flip-flop) between monolayers occurs in the pore surface region in all the cases considered. These findings expand our understanding of the antimicrobial peptide resistance properties of probiotic strains.

Differential activity of lytic α-helical peptides on lactobacilli and lactobacilli-derived liposomes

Eukaryotic antimicrobial peptides (AMPs) interact with plasma membrane of bacteria, fungi and eukaryotic parasites. Noteworthy, Lactobacillus delbrueckii subsp. lactis (CIDCA 133) and L. delbrueckii subsp. bulgaricus (CIDCA 331) show different susceptibility to human beta-defensins (β-sheet peptides). In the present work we extended the study to α-helical peptides from anuran amphibian (Aurein 1.2, Citropin 1.1 and Maculatin 1.1). We studied the effect on whole bacteria and liposomes formulated with bacterial lipids through growth kinetics, flow cytometry, leakage of liposome content and studies of peptide insertion in lipid monolayers. Growth of strain CIDCA 331 was dramatically inhibited in the presence of all three peptides and minimal inhibitory concentrations were lower than those for strain CIDCA 133. Flow cytometry revealed that AMPs lead to the permeabilization of bacteria. In addition, CIDCA 331-derived liposomes showed high susceptibility, leading to content leakage and structural disruption. Accordingly, peptide insertion in lipid monolayers demonstrated spontaneous interaction of AMPs with CIDCA 331 lipids. In contrast, lipids monolayers from strain CIDCA 133 were less susceptible. Summarizing we demonstrate that the high resistance of the probiotic strain CIDCA 133 to AMPs extends to α helix peptides Aurein, Citropin and Maculatin. This behavior could be ascribed in part to differences in membrane composition. These findings, along with the previously demonstrated resistance to β defensins from human origin, suggest that strain CIDCA 133 is well adapted to host innate immune effectors from both mammals and amphibians thus indicating conserved mechanisms of interaction with key components of the innate immune system.