Mixed-species biofilm formation by lactic acid bacteria and rice wine yeasts

We found that species combinations such as Lactobacillus casei subsp. rhamnosus IFO3831 and Saccharomyces cerevisiae Kyokai-10 can form a mixed-species biofilm in coculture. Moreover, the Kyokai-10 yeast strain can form a biofilm in monoculture in the presence of conditioned medium (CM) from L. casei IFO3831. The active substance(s) in bacterial CM is heat sensitive and has a molecular mass of between 3 and 5 kDa. In biofilms from cocultures or CM monocultures, yeast cells had a distinct morphology, with many hill-like protrusions on the cell surface.     

Lactic Acid Production in a Mixed-Culture Biofilm Reactor

Novel solid supports, consisting of polypropylene blended with various agricultural materials (pp composite), were evaluated as supports for pure- and mixed-culture continuous lactic acid fermentations in biofilm reactors. Streptomyces viridosporus T7A (ATCC 39115) was used to form a biofilm, and Lactobacillus casei subsp. rhamnosus (ATCC 11443) was used for lactic acid production. For mixed-culture fermentations, a 15-day continuous fermentation of S. viridosporus was performed initially to establish the biofilm. The culture medium was then inoculated with L. casei subsp. rhamnosus. For pure-culture fermentation, L. casei subsp. rhamnosus was inoculated directly into the reactors containing sterile pp composite chips. The biofilm reactors containing various pp composite chips were compared with a biofilm reactor containing pure polypropylene chips and with a reactor containing a suspension culture. Continuous fermentation was started, and each flow rate (0.06 to 1.92 ml/min) was held constant for 24 h; steady state was achieved after 10 h. Lactic acid production was determined throughout the 24-h period by high-performance liquid chromatography. Production rates that were two to five times faster than those of the suspension culture (control) were observed for the pure- and mixed-culture bioreactors. Both lactic acid production rates and lactic acid concentrations in the culture medium were consistently higher in mixed-culture than in pure-culture fermentations. Biofilm formation on the chips was detected at harvest by chip clumping and Gram staining.     

Increase in antioxidant enzyme activity,stress tolerance and biocontrol efficacy of Pichia kudriavzevii with the transition from a yeast-like to biofilm morphology

Morphological change, such as from yeast-like to biofilm, has been recently considered to be involved in the mode of action of some antagonistic yeasts used as postharvest biocontrol agents. In the present study, the biocontrol yeast, Pichia kudriavzevii, reversibly shifted from a yeast-like morphology on yeast peptone dextrose (YPD) medium with 2% agar to a biofilm morphology on YPD with 0.3% agar. The tolerance of P. kudriavzevii to heat and oxidative stresses, as well as the biocontrol efficacy against postharvest diseases on pear fruit, increased significantly from the yeast-like form to the biofilm form. The activity of antioxidant enzymes, including catalase and superoxidase dismutase, in the biofilm form was also significantly higher. The elevated activity of antioxidant enzymes was associated with less protein and lipid oxidation in the biofilm form, compared to the yeast-like form, under heat and oxidative stresses. These results suggest that activation of antioxidant system with the morphology shift contributes to the enhancement of abiotic stress tolerance and biocontrol performance of P. kudriavzevii. These findings provide new information on the biology of yeast antagonists that is essential for their potential application and development.     

Solubilization of a novel isoflavone glycoside-hydrolyzing β-glucosidase from Lactobacillus casei subsp. rhamnosus

A novel isoflavone glycoside-hydrolyzing β-glucosidase produced by Lactobacillus casei subsp. rhamnosus IFO 3425 was solubilized by ultrasonic disruption of the cells in the presence of 2-mercaptoethanol and sorbitol as stabilizer. The β-glucosidase from L. casei subsp. rhamnosus specifically hydrolyzed soybean isoflavone glycosides, namely, daidzin and genistin, converting them to daidzein and genistein, respectively. By contrast, a commercial preparation of almond emulsin β-glucosidase could not hydrolyze these soybean isoflavone glycosides. The undesirably bitter and astringent isoflavone glycosides in soybean were decomposed for the first time with this novel β-glucosidase, an enzyme which has hitherto been considered difficult to solubilize, produced by a lactic acid bacterium.     

Development of a toxR-based loop-mediated isothermal amplification assay for detecting Vibrio parahaemolyticus

Background

Microbial cell-cell interactions in the oral flora are believed to play an integral role in the development of dental plaque and ultimately, its pathogenicity. The effects of other species of oral bacteria on biofilm formation and virulence gene expression by Streptococcus mutans, the primary etiologic agent of dental caries, were evaluated using a dual-species biofilm model and RealTime-PCR analysis.

Results

As compared to mono-species biofilms, biofilm formation by S. mutans was significantly decreased when grown with Streptococcus sanguinis, but was modestly increased when co-cultivated with Lactobacillus casei. Co-cultivation with S. mutans significantly enhanced biofilm formation by Streptococcus oralis and L. casei, as compared to the respective mono-species biofilms. RealTime-PCR analysis showed that expression of spaP (for multi-functional adhesin SpaP, a surface-associated protein that S. mutans uses to bind to the tooth surface in the absence of sucrose), gtfB (for glucosyltransferase B that synthesizes α1,6-linked glucan polymers from sucrose and starch carbohydrates) and gbpB (for surface-associated protein GbpB, which binds to the glucan polymers) was decreased significantly when S. mutans were co-cultivated with L. casei. Similar results were also found with expression of spaP and gbpB, but not gtfB, when S. mutans was grown in biofilms with S. oralis. Compared to mono-species biofilms, the expression of luxS in S. mutans co-cultivated with S. oralis or L. casei was also significantly decreased. No significant differences were observed in expression of the selected genes when S. mutans was co-cultivated with S. sanguinis.

Conclusions

These results suggest that the presence of specific oral bacteria differentially affects biofilm formation and virulence gene expression by S. mutans.     

Impact of Environmental and Genetic Factors on Biofilm Formation by the Probiotic Strain Lactobacillus rhamnosus GG

Lactobacillus rhamnosus GG (ATCC 53103) is one of the clinically best-studied probiotic organisms. Moreover, L. rhamnosus GG displays very good in vitro adherence to epithelial cells and mucus. Here, we report that L. rhamnosus GG is able to form biofilms on abiotic surfaces, in contrast to other strains of the Lactobacillus casei group tested under the same conditions. Microtiter plate biofilm assays indicated that in vitro biofilm formation by L. rhamnosus GG is strongly modulated by culture medium factors and conditions related to the gastrointestinal environment, including low pH; high osmolarity; and the presence of bile, mucins, and nondigestible polysaccharides. Additionally, phenotypic analysis of mutants affected in exopolysaccharides (wzb), lipoteichoic acid (dltD), and central metabolism (luxS) showed their relative importance in biofilm formation by L. rhamnosus GG.     

Genomic Adaptation of the Lactobacillus casei Group

Lactobacillus casei, L. paracasei, and L. rhamnosus form a closely related taxonomic group (Lactobacillus casei group) within the facultatively heterofermentative lactobacilli. Here, we report the complete genome sequences of L. paracasei JCM 8130 and L. casei ATCC 393, and the draft genome sequence of L. paracasei COM0101, all of which were isolated from daily products. Furthermore, we re-annotated the genome of L. rhamnosus ATCC 53103 (also known as L. rhamnosus GG), which we have previously reported. We confirmed that ATCC 393 is distinct from other strains previously described as L. paracasei. The core genome of 10 completely sequenced strains of the L. casei group comprised 1,682 protein-coding genes. Although extensive genome-wide synteny was found among the L. casei group, the genomes of ATCC 53103, JCM 8130, and ATCC 393 contained genomic islands compared with L. paracasei ATCC 334. Several genomic islands, including carbohydrate utilization gene clusters, were found at the same loci in the chromosomes of the L. casei group. The spaCBA pilus gene cluster, which was first identified in GG, was also found in other strains of the L. casei group, but several L. paracasei strains including COM0101 contained truncated spaC gene. ATCC 53103 encoded a higher number of proteins involved in carbohydrate utilization compared with intestinal lactobacilli, and extracellular adhesion proteins, several of which are absent in other strains of the L. casei group. In addition to previously fully sequenced L. rhamnosus and L. paracasei strains, the complete genome sequences of L. casei will provide valuable insights into the evolution of the L. casei group.     

Characterization of Mucosal Candida albicans Biofilms

C. albicans triggers recurrent infections of the alimentary tract mucosa that result from biofilm growth. Although the ability of C. albicans to form a biofilm on abiotic surfaces has been well documented in recent years, no information exists on biofilms that form directly on mucosal surfaces. The objectives of this study were to characterize the structure and composition of Candida biofilms forming on the oral mucosa. We found that oral Candida biofilms consist of yeast, hyphae, and commensal bacteria, with keratin dispersed in the intercellular spaces. Neutrophils migrate through the oral mucosa and form nests within the biofilm mass. The cell wall polysaccharide β-glucan is exposed during mucosal biofilm growth and is more uniformly present on the surface of biofilm organisms invading the oral mucosa. We conclude that C. albicans forms complex mucosal biofilms consisting of both commensal bacterial flora and host components. These discoveries are important since they can prompt a shift of focus for current research in investigating the role of Candida-bacterial interactions in the pathogenesis of mucosal infections as well as the role of β-glucan mediated signaling in the host response.     

Production of a Heterologous Nonheme Catalase by Lactobacillus casei: an Efficient Tool for Removal of H2O2 and Protection of Lactobacillus bulgaricus from Oxidative Stress in Milk

Lactic acid bacteria (LAB) are generally sensitive to H₂O₂, a compound that they can paradoxically produce themselves, as is the case for Lactobacillus bulgaricus. Lactobacillus plantarum ATCC 14431 is one of the very few LAB strains able to degrade H₂O₂ through the action of a nonheme, manganese-dependent catalase (hereafter called MnKat). The MnKat gene was expressed in three catalase-deficient LAB species: L. bulgaricus ATCC 11842, Lactobacillus casei BL23, and Lactococcus lactis MG1363. While the protein could be detected in all heterologous hosts, enzyme activity was observed only in L. casei. This is probably due to the differences in the Mn contents of the cells, which are reportedly similar in L. plantarum and L. casei but at least 10- and 100-fold lower in Lactococcus lactis and L. bulgaricus, respectively. The expression of the MnKat gene in L. casei conferred enhanced oxidative stress resistance, as measured by an increase in the survival rate after exposure to H₂O₂, and improved long-term survival in aerated cultures. In mixtures of L. casei producing MnKat and L. bulgaricus, L. casei can eliminate H₂O₂ from the culture medium, thereby protecting both L. casei and L. bulgaricus from its deleterious effects.     

Development of a stable shuttle vector and a conjugative transfer system for Gluconobacter oxydans

A shuttle vector pGE1 (11.9 kb) which can replicate both in Gluconobacter oxydans and Escherichia coli was constructed from the cryptic Gluconobacter plasmid pGO3293S (9.9 kb, relaxed type) and E. coli plasmid pSUP301 (5 kb, Km^r, Ap^r, relaxed type). The plasmid pGO3293S is one of the endogenous plasmids of G. oxydans IFO 3293 which converts l-sorbose to 2-keto-l-gulonic acid (2KGA), an intermediate of vitamin C synthesis. The other plasmid, pSUP301, is a conjugative plasmid which contains pACYC177 and the mob region from plasmid RP4. The plasmid pGE1 could be transferred into G. oxydans IFO 3293 with a high frequency (10⁻¹ transconjugants/recipient) by a conjugal transfer system, and maintained very stably without antibiotic selection. pGE1 can be introduced and maintained in other acetic acid bacteria including Gluconobacter and Acetobacter. The presence of pGE1 did not inhibit the growth or 2KGA productivity of 2KGA-producing strains derived from G. oxydans IFO 3293. The usefulness of pGE1 as a vector was confirmed by subcloning the membrane-bound l-sorbosone dehydrogenase gene of A. liquefaciens IFO 12258 in G. oxydans IFO 3293 derivatives; in this subcloning, pGE1 could be further shortened to the 9.8 kb plasmid, pGE2.     

Diphenyl diselenide (PhSe)2 inhibits biofilm formation by Candida albicans,increasing both ROS production and membrane permeability

ProjectThe opportunistic fungal Candida albicans can produce superficial and systemic infections in immunocompromised patients. An essential stage to both colonization and virulence by C. albicans is the transition from budding yeast form to filamentous form, producing biofilms.ProcedureIn this work, we studied the effect of the organochalcogenide compound (PhSe)₂ on both cell growth and biofilm formation by C. albicans.Results(PhSe)₂ inhibited both growth and biofilm formation by C. albicans. The inhibitory effects of (PhSe)₂ depended on the cell density and (PhSe)₂ concentration. We have also observed that (PhSe)₂ stimulated ROS production (67%) and increased cell membrane permeability (2.94-fold) in C. albicans. In addition, (PhSe)₂ caused a marked decrease in proteinase activity (6.8-fold) in relation to non-treated group.Conclusions(PhSe)₂ decreased both cell growth and biofilm development, decreasing the release of extracellular proteinases, which is an important facet of C. albicans pathogenicity. The toxicity of (PhSe)₂ towards C. albicans can be associated with an increase in ROS production, which can increase cell permeability. The permanent damage to the cell membranes can culminate in cell death.     

A comparative study of the effect of probiotics on cariogenic biofilm model for preventing dental caries

Dental caries is induced by oral biofilm containing Streptococcus mutans. Probiotic bacteria were mainly studied for effect on the gastrointestinal tract and have been known to promote human health. However, the information of probiotics for oral health has been lack yet. In this study, we investigated influence of various probiotics on oral bacteria or cariogenic biofilm and evaluated candidate probiotics for dental caries among them. The antimicrobial activity of the spent culture medium of probiotics for oral streptococci was performed. Probiotics were added during the biofilm formation with salivary bacteria including S. mutans. The oral biofilms were stained with a fluorescent dye and observed using the confocal laser scanning microscope. To count bacteria in the biofilm, the bacteria were plated on MSB and BHI agar plates after disrupting the biofilm and cultivated. Glucosyltransferases (gtfs) expression of S. mutans and integration of lactobacilli into the biofilm were evaluated by real-time RT-PCR. Among probiotics, Lactobacillus species strongly inhibited growth of oral streptococci. Moreover, Lactobacillus species strongly inhibited formation of cariogenic biofilm model. The expression of gtfs was significantly reduced by Lactobacillus rhamnosus. The integration of L. rhamnosus into the biofilm model did not exhibit. However, L. acidophilus and L casei integrated into the biofilm model. These results suggest that L. rhamnosus may inhibit oral biofilm formation by decreasing glucan production of S. mutans and antibacterial activity and did not integrate into oral biofilm, which can be a candidate for caries prevention strategy.     

Quantitative Detection of Corynebacterium casei in Cheese by Real-Time PCR

The flora on the surface of smear-ripened cheeses is composed of numerous species of bacteria and yeasts that contribute to the production of the desired organoleptic properties. Due to the absence of selective media, it is very difficult to quantify cheese surface bacteria, and, consequently, the ecology of the cheese surface microflora has not been extensively investigated. We developed a SYBR green I real-time PCR method to quantify Corynebacterium casei, a major species of smear-ripened cheeses, using primers designed to target the 16S rRNA gene. It was possible to recover C. casei genomic DNA from the cheese matrix with nearly the same yield that C. casei genomic DNA is recovered from cells recovered by centrifugation from liquid cultures. Quantification was linear over a range from 10⁵ to 10¹⁰ CFU per g of cheese. The specificity of the assay was demonstrated with DNA from species related to C. casei and from other bacteria and yeasts belonging to the cheese flora. Nine commercial cheeses were analyzed by real-time PCR, and six of them were found to contain more than 10⁵ CFU equivalents of C. casei per g. In two of them, the proportion of C. casei in the total bacterial flora was nearly 40%. The presence of C. casei in these samples was further confirmed by single-strand conformation polymorphism analysis and by a combined approach consisting of plate counting and 16S rRNA gene sequencing. We concluded that SYBR green I real-time PCR may be used as a reliable species-specific method for quantification of bacteria from the surface of cheeses.     

The mechanism of action of reactivating factor from <Emphasis Type="Italic">Luteococcus japonicus</Emphasis> subsp. <Emphasis Type="Italic">casei</Emphasis>

Reactivating factor (RF) from Luteococcus japonicus subsp. casei was shown to be constitutively synthesized and to act a by one-step mechanism, being activated independently from stress. Cell reactivation (reversion of a cell’s ability to form macrocolonies) might be ensured by the membrane mechanism of RF action, which is proved with the dependence of antistress activity from the condition of the cytoplasmic membrane and with the form of concentration dependence. The incubation of UV-treated L. casei suspension with RF increased the number of cells with intact barrier membrane (1.6–1.8-fold increase compared to RF-untreated cells) and the number of colony-forming cells. Cross defensive and reactivating RF effects on both L. casei and yeast Saccharomyces cerevisiae cells were described. Bacterial and yeast’s RF compete for membrane receptors. Matrix Assisted Laser Desorption/Ionization time-of-flight (MALDI-TOF) spectrometry revealed that RF of L. casei contained two major peptides of 5.8 and 7.6 kDa, while RF of S. cerevisiae was represented by a single peptide of 5.8 kDa. The presence of 5.8 kDa peptide in RF from bacteria and yeasts might ensure cross responses in these organisms.     

Complete Genome Sequence of Lactobacillus casei Zhang,a New Probiotic Strain Isolated from Traditional Homemade Koumiss in Inner Mongolia,China

Lactobacillus casei Zhang is a new probiotic bacterium isolated from koumiss collected in Inner Mongolia, China. Here, we report the main genome features of L. casei Zhang and the identification of several predicted proteins implicated in interactions with the host.Koumiss, a traditional drink made from mare''s milk by nomadic peoples in China and Mongolia, is believed to be beneficial in the cure of digestive diseases and a wide range of chronic diseases, including tuberculosis, bronchitis, and anemia (3). Lactobacillus casei Zhang is a novel probiotic strain identified by screening of lactic acid bacteria isolated from koumiss samples collected in Inner Mongolia, China, and exhibits high-level resistance to acid and bile stresses, as well as antibacterial, antioxidative, and immunomodulatory properties (6, 7, 11).A whole-genome shotgun strategy was used for sequencing of the genome of L. casei Zhang. pUC18 plasmid libraries with insertions of 1.5 to 2.5 kb and 4 to 6 kb were constructed (8). Gaps were closed by sequencing of PCR products. Base calling and sequence assembly were carried out using the Phred/Phrap/Consed software package (http://www.phrap.org/), and reads giving a total of 6.2-fold coverage were assembled with an error rate of <0.0001. Gene prediction and annotation were performed as described previously (10).The complete genome of L. casei Zhang consists of a 2,861,848-bp circular chromosome and a 36-kb plasmid. The average G+C content of the chromosome is 46.5%, while the plasmid has a lower G+C content (10). The L. casei Zhang genome contains 2,804 predicted coding sequences (CDSs), five rRNA operons, and 59 tRNAs. No functional prophages were identified, except for the previously described prophage remnant (9). Genes for 41 transposases were found in the genome, and this number was much lower than (only about 30%) those of transposase genes in L. casei ATCC 334 and BL23 (1, 4), suggesting that insertion element (IS)-mediated genome diversification was less frequent in L. casei Zhang.Comparative genome analysis revealed that the number of phosphotransferase system (PTS)-related proteins varied significantly in L. casei strains. Almost twice as many PTS components were found in L. casei Zhang and BL23 as in L. casei ATCC 334. In contrast to L. casei ATCC 334, L. casei Zhang was found to have 33 PTS components consisting of 11 complete substrate-specific enzyme II (EII) complexes encoded by six genomic islands. The G+C contents of the six islands ranged from 41 to 47%, similar to the average G+C content of the L. casei Zhang genome. In addition, most of the EII components in L. casei Zhang (81 of 96) were conserved in L. casei BL23, suggesting that a large-scale loss of PTSs occurred in L. casei ATCC 334 during its evolution. Conspicuous redundancy of chromosome-encoded PTSs in L. casei Zhang may offer benefits in the transport and use of a large panel of carbon sources.Genes encoding five putative mucus-binding proteins (LCAZH_0407, LCAZH_2292, LCAZH_2478, LCAZH_2398, and LCAZH_1427) and a cluster of genes encoding bacteriocin biosynthetic proteins (LCAZH_2341 to LCAZH_2348) nearly identical to those in L. casei ATCC 334 and BL23 were identified in L. casei Zhang and may provide this bacterium with some competitive advantages in the gastrointestinal environment (2, 5).In conclusion, the comparative analysis revealed the flexibility of L. casei Zhang in sugar utilization. In addition, some possible hints for its interactions with the host were identified. This genome sequence will be the basis for systematic studies into the mechanism for the probiotic properties of L. casei Zhang.     

Characterization of the Lactobacillus casei group based on the profiling of ribosomal proteins coded in S10-spc-alpha operons as observed by MALDI-TOF MS

The taxonomy of the members of the Lactobacillus casei group is complicated because of their phylogenetic similarity and controversial nomenclatural status. In this study, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) of ribosomal proteins coded in the S10-spc-alpha operon, termed S10-GERMS, was applied in order to classify 33 sample strains belonging to the L. casei group. A total of 14 types of ribosomal protein genes coded in the operon were first sequenced from four type strains of the L. casei group (L. casei JCM 1134^T, L. paracasei subsp. paracasei JCM 8130^T, L. paracasei subsp. tolerans JCM 1171^T, and L. rhamnosus JCM 1136^T) together with L. casei JCM 11302, which is the former type strain of ‘L. zeae’. The theoretical masses of the 14 types of ribosomal proteins used as biomarkers were classified into five types and compiled into a ribosomal protein database. The observed ribosomal proteins of each strain, identified by MALDI-TOF MS, were categorized into types based on their masses, summarized as ribosomal protein profiles, and they were used to construct a phylogenetic tree. The 33 sample strains, together with seven genome-sequenced strains, could be classified into four major clusters, which coincided precisely with the taxa of the (sub)species within the L. casei group. Three “ancient” strains, identified as L. acidophilus and L. casei, were correctly re-identified as L. paracasei subsp. paracasei by S10-GERMS. S10-GERMS would thus appear to be a powerful tool for phylogenetic characterization, with considerable potential for management of culture collections.     

Formation of In Vitro Mixed-Species Biofilms by Lactobacillus pentosus and Yeasts Isolated from Spanish-Style Green Table Olive Fermentations

The present work details the in vitro interactions between Lactobacillus pentosus and yeast strains isolated from table olive processing to form mixed biofilms. Among the different pairs assayed, the strongest biofilms were obtained from L. pentosus and Candida boidinii strain cocultures. However, biofilm formation was inhibited in the presence of d-(+)-mannose. In addition, biofilm formation by C. boidinii monoculture was stimulated in the absence of cell-cell contact with L. pentosus. Scanning electron microscopy revealed that a sort of “sticky” material formed by the yeasts contributed to substrate adherence. Hence, the data obtained in this work suggest that yeast-lactobacilli biofilms may be favored by the presence of a specific mate of yeast and L. pentosus, and that more than one mechanism might be implicated in the biofilm formation. This knowledge will help in the design of appropriate mixed starter cultures of L. pentosus-yeast species pairs that are able to improve the quality and safety of Spanish-style green table olive processing.     

Lactobacillus casei Exerts Anti-Proliferative Effects Accompanied by Apoptotic Cell Death and Up-Regulation of TRAIL in Colon Carcinoma Cells

Probiotic microorganisms such as lactic acid bacteria (LAB) exert a number of strain-specific health-promoting activities attributed to their immunomodulatory, anti-inflammatory and anti-carcinogenic properties. Despite recent attention, our understanding of the biological processes involved in the beneficial effects of LAB strains is still limited. To this end, the present study investigated the growth-inhibitory effects of Lactobacillus casei ATCC 393 against experimental colon cancer. Administration of live Lactobacillus casei (as well as bacterial components thereof) on murine (CT26) and human (HT29) colon carcinoma cell lines raised a significant concentration- and time-dependent anti-proliferative effect, determined by cell viability assays. Specifically, a dramatic decrease in viability of colon cancer cells co-incubated with 10⁹ CFU/mL L. casei for 24 hours was detected (78% for HT29 and 52% for CT26 cells). In addition, live L. casei induced apoptotic cell death in both cell lines as revealed by annexin V and propidium iodide staining. The significance of the in vitro anti-proliferative effects was further confirmed in an experimental tumor model. Oral daily administration of 10⁹ CFU live L. casei for 13 days significantly inhibited in vivo growth of colon carcinoma cells, resulting in approximately 80% reduction in tumor volume of treated mice. Tumor growth inhibition was accompanied by L. casei-driven up-regulation of the TNF-related apoptosis-inducing ligand TRAIL and down-regulation of Survivin. Taken together, these findings provide evidence for beneficial tumor-inhibitory, anti-proliferative and pro-apoptotic effects driven by this probiotic LAB strain.