Bioactivity characterization of Lactobacillus strains isolated from dairy products

Gamma Amino Butyric Acid (GABA) and Ferulic Acid Esterase (FAE) Producing Psychobiotic Bacteria Isolated from Cereal-Based Fermented Food

Gut microbiota plays an important role in regulating enteric, immune and neural pathways. Many neuropsychiatric disorders such as anxiety, depression, autism and cognitive behaviour are associated with gut dysbiosis. Gamma-aminobutyric acid (GABA) and short-chain fatty acids produced by gut bacteria influence gastrointestinal and neurological functions. Ferulic acid esterase (FAE) which releases ferulic acid (FA) from feruloylated sugar ester conjugates, naturally found in grains, fruits and vegetables, is also produced by some gut bacteria and helps prevent neurodegeneration. These properties provide bacteria with the ability to maintain intestinal barrier function and prevent neuropsychiatric disorders. Therefore, this study aims to isolate GABA and FAE-producing LAB and characterize their bioactive and probiotic properties. A total of twelve cultures were isolated, of which eight bacteria positive for GABA, FAE and SCFA production were selected for further investigation. All selected bacteria were positive for bile salt hydrolase (BSH) and showed acid tolerance, resistance to bile salt, stimulated gastric and pancreatic juice, and auto- and co-aggregation properties. Furthermore, selected LAB showed mucin adhesion efficiency greater than 80% and exhibited γ-hemolytic activity. 16S rRNA sequencing identified NS0969, B1, C1, C2, M1, M2, and R2 as Limosilactobacillus fermentum and R1 as Lactiplantibacillus pentosus. This study showed that selected bacteria and/or their postbiotic preparations can be used as potential psychobiotics.

Application of pre-adaptation strategies to improve the growth of probiotic lactobacilli under food-relevant stressful conditions

While formulating a probiotic food, it is mandatory to make sure that the viability of probiotics is adequate at the point of consumption, which can be strongly compromised by stressful conditions due to low pH and high osmolarity. In this study, three probiotic lactobacilli were subjected to different pre-adaptation conditions, and the turbidimetric growth kinetics in challenging conditions (pH 4.0-6.5, NaCl 1-7%, sucrose 0.1-0.7 M) were evaluated. Different effects were observed for Lactobacillus acidophilus, Lacticaseibacillus casei, and Lactiplantibacillus plantarum. Indeed, pre-exposition to sub-optimal conditions in terms of pH and % NaCl significantly improved the ability of L. acidophilus and L. casei to overcome the osmotic stress due to salt or sucrose, and similar effects were observed for acidic stress. L. plantarum showed to be more tolerant to the challenging conditions applied in this study. Anyway, the pre-adaptation at conditions SUB_1 (pH 4.5 and NaCl 4%) and SUB_2 (pH 5 and NaCl 2%) speeded-up its growth kinetics by reducing the length of the lag phase under sucrose stress and enhancing the maximum growth rate at the highest pH tested. Moreover, an improvement in biomass amount was observed under sucrose stress. The whole data evidenced that the application of the appropriate pre-adaptation condition could contribute to making probiotics more robust towards challenging conditions due to food matrix, processing, and storage as well as gastrointestinal transit. Further studies will be necessary to gain insight into the proteomics and metabolomics responsible for increased tolerance to stressful conditions.

Lactobacillus casei condition medium downregulates miR-21 relative expression in HT-29 colorectal cancer cell line

Previous research has demonstrated promising outcomes regarding the advantageous impact of probiotics in both cancer prevention and treatment. Nevertheless, the precise molecular mechanisms underpinning these effects remain elusive. Recent investigations have proposed a potential involvement of micro ribonucleic acids (miRNAs) in mediating the favorable influence of probiotics on cancerous cells. This study was designed to evaluate the effect of Lactobacillus casei condition medium on miR-21 relative expression in HT-29 colorectal cancer cells. Lactobacillus casei condition medium mixed with RPMI in different proportions (1:1, 1:3, and 1:7) and utilized to treat HT-29 cells for 24 and 48 h. Subsequently, percentage of early and late apoptotic cells were identified using a flow cytometry instrument. A real-time polymerase chain reaction was carried out to determine the relative expression of miR-21. Our findings revealed that L. casei condition medium induces apoptosis in a time- and dose-dependent manner in HT-29 cells. Furthermore, we found a significantly downregulated miR-21 after treatment with high doses of L. casei condition medium after 48 h. Overall, our results provide valuable insights into a potential mechanism through which L. casei condition medium mediates its apoptotic effect in colorectal cancer cells through downregulation of miR-21. However, further investigations are required to unravel its therapeutic, diagnostic, and treatment monitoring potential.

Identification of Novel Bile Salt-Tolerant Genes in Lactobacillus Using Comparative Genomics and Its Application in the Rapid Screening of Tolerant Strains

Under bile salt treatment, strains display significant differences in their tolerance ability, suggesting the existence of diverse resistance mechanisms in Lactobacillus; however, the genes involved in this protective process are not fully understood. In this study, novel target genes associated with bile salt tolerance in Lactobacillus were identified using comparative genomics for PCR detection and the rapid screening of tolerant strains. The bile salt tolerance of 107 lactobacilli isolated from different origins was assessed, and 26 strains with comparatively large differences were selected for further comparative genomic analysis. Tolerant strains had 112 specific genes that were enriched in the phosphotransferase system, the two-component system, carbohydrate metabolism, and the ATP-binding cassette transporter. Six genes from Lactobacillus were cloned into the inducible lactobacillal expression vector pSIP403. Overexpression in the host strain increased its tolerance ability by 11.86-18.08%. The novel genes identified here can be used as targets to design primers for the rapid screening of bile salt-tolerant lactobacilli. Altogether, these results deepen our understanding of bile salt tolerance mechanisms in Lactobacillus and provide a basis for further rapid assessments of tolerant strains.

Administration of microencapsulated Enterococcus faecium ABRIINW.N7 with fructo-oligosaccharides and fenugreek on the mortality of tilapia challenged with Streptococcus agalactiae

We investigated the probiotic potential of a microencapsulated Enterococcus faecium ABRIINW.N7 for control of Streptococcus agalactiae infection in hybrid (Oreochromis niloticus × Oreochromis mossambicus) red tilapia. A two-phase experiment approach was completed in which E. faecium bacteria were propagated, from which a culture was isolated, identified using molecular techniques, and microencapsulated to produce a stable commercial fructooligosaccharide (FOS) and fenugreek (Fk) product of optimal concentration. The FOS and Fk products were assessed in a 90-days in vivo challenge study, in which red hybrid tilapia were allocated to one of five treatments: (1) No Streptococcus agalactiae (Sa) challenge (CON); (2) Sa challenge only (CON+); (3) Sa challenge in a free cell (Free Cell); (4) Sa challenge with 0.8% (w/v) Alginate; (5) Microencapsulated FOS and Fk. In vitro results showed high encapsulation efficiency (≥98.6 ± 0.7%) and acceptable viability of probiotic bacteria within the simulated fish digestive system and high stability of viable cells in all gel formulations (34 < SR% <63). In vivo challenges demonstrated that the FOS and Fk products could be used to control S. agalactiae infection in tilapia fish and represented a novel investigation using microencapsulation E. faecium as a probiotic diet for tilapia fish to control S. agalactiae infection and to lower fish mortality. It is recommended that local herbal gums such as 0.2% Persian gum and 0.4% Fk in combination with 0.8% alginate (Formulation 7) can be used as a suitable scaffold and an ideal matrix for the encapsulation of probiotics. These herbal gums as prebiotics are capable of promoting the growth of probiotic cells in the food environment and digestive tract.

Anticancer Potential of Post-Fermentation Media and Cell Extracts of Probiotic Strains: An In Vitro Study

Simple Summary

Probiotics and their metabolites are very important for human health. The aim of this research was to determine probiotic strains with the strongest inhibitory properties against intestinal cancer cells. As a result of the screening, it was possible to find two strains, i.e., Lactiplantibacillus plantarum 0991 and Levilactobacillus brevis 0983, that could inhibit the proliferation of cancer cells by induction of oxidative stress and programmed cell death. Both strains exhibit interesting anticancer properties and potential as functional food ingredients; however, the results must be confirmed in further research.

Abstract

Background: Lactic acid bacteria (LAB), many of which are probiotics, can produce health-promoting metabolites (postbiotics). Purpose: To assess the mechanism of antiproliferative action of postbiotics, post-fermentation media (PFM) and cell extracts (CEs) of several strains of LAB were studied against colon (Caco-2), and cervix (HeLa) cancer cell lines, as well as normal intestine (IEC-6) cells, were used as a comparison. Methods: Postbiotics of various LAB (n = 39) were screened for their antiproliferative activity. The effect of PFM and CEs on reactive oxygen species (ROS), mitochondrial membrane potential (MMP), ATP production, phosphatidylserine (PS) externalisation, and apoptosis-related caspases 3/7 and 9 activation was assayed. Results: PFM and CEs showed strong dose-dependent antiproliferative activity against Caco-2 cells, up to 77.8 ± 0.8% and 58.4 ± 1.6% for PFM and CEs, respectively. Stronger inhibitory activity against cancerous (Caco-2 and HeLa) cells than against normal (IEC-6) cells was observed. PFM were more inhibitory than CEs, and both generated oxidative stress in Caco-2 cells. PFM of L. plantarum 0991 and L. brevis 0983 induced apoptosis in Caco-2 cells by the mitochondrial signalling pathway. Conclusions: Anticancer activity of PFM and CEs of LAB, as well as the ability of apoptosis induction, is strain-specific.

In vitro evaluation of probiotic properties of lactic acid bacteria isolated from the vagina of yak (Bos grunniens)

Bovine endometritis is an inflammatory disease of the uterus that occurs after parturition and can result in the destruction of uterine microecology, disruption of hormone secretion, and even infertility. Problems such as antibiotic residues, pathogen resistance, and microbiota dysbiosis caused by conventional antibiotic therapy cannot be ignored. According to the microecological balance theory, probiotics have the potential to prevent or cure endometritis in cattle. Probiotics can positively influence host physiology by regulating microecological imbalance, modulating immunity, and antagonizing pathogens. Since some probiotics contribute to host health only in their specific natural niches, lactic acid bacteria (LAB) from the vagina may have better potential to fight against vaginal and uterine infection. The yak (Bos grunniens) is an ancient and primitive livestock animal that is adapted to high altitude and harsh environments (cold, nutritional deficiencies, and hypoxia). However, to our knowledge, there have been no studies on yak vaginal LAB. Therefore, the purpose of this study was to isolate vaginal LAB from yak, evaluate and compare the probiotic potential and safety of the isolates, and help establish the probiotics library that can be used in the prevention and/or treatment of endometritis. Twenty-five vaginal swabs were collected from healthy yak and cultured in deMan, Rogosa, and Sharpe (MRS) broth. Tentative LAB strains were preliminarily determined through calcium dissolving zone and morphological identification, and the strains were then identified using 16S rRNA gene sequencing. The probiotics of the isolates were detected using cell aggregation, hydrophobicity, resistance to acid and bile salt, adhesion, and antibacterial activities. Additionally, antimicrobial susceptibility, hemolytic activity, and detection of potential virulence factors were determined in order to confirm the safety of these strains. Five isolates were identified: Leuconostoc mesenteroides, Lactobacillus plantarum, Enterococcus hirae, Lacticaseibacillus camelliae, and Lactobacillus mucosae. All isolates had certain growth resistance, aggregation ability, effective antimicrobial potency against Escherichia coli, Staphylococcus aureus, and Salmonella typhimurium, were sensitive to most antibiotics, and could effectively adhere to bovine endometrial epithelial cells (BEECs). None of the isolates showed hemolytic activity or harbored virulence factors. Our results indicated that the five isolates have considerable potential as probiotics that can be used to prevent and/or treat bovine endometritis. We speculate that a mixture of YD6, YD9, and YD25 may yield better results, although this would require extensive experiments to verify.

Metabolomics of acid whey derived from Greek yogurt

Acid whey, a byproduct of Greek yogurt production, has little commercial value due to its low protein content and is also environmentally harmful when disposed of as waste. However, as a product of microbial fermentation, acid whey could be a rich source of beneficial metabolites associated with fermented foods. This study increases understanding of acid whey composition by providing a complete metabolomic profile of acid whey. Commercial and laboratory-made Greek yogurts, prepared with 3 different bacterial culture combinations, were evaluated. Samples of uncultured milk and cultured whey from each batch were analyzed. Ultra-high-performance liquid chromatography-tandem mass spectrometry metabolomics were used to separate and identify 477 metabolites. Compared with uncultured controls, acid whey from fermented yogurt showed decreases in some metabolites and increases in others, presumably due to the effects of microbial metabolism. Additional metabolites appeared in yogurt whey but not in the uncultured control. Therefore, the effect of microbial fermentation is complex, leading to increases or decreases in potentially bioactive bovine metabolites while generating new microbial compounds that may be beneficial. Metabolite production was significantly affected by combinations of culturing organisms and production location. Differences between laboratory-made and commercial samples could be caused by different starting ingredients, environmental factors, or both.

Review of the bacterial composition of healthy milk, mastitis milk and colostrum in small ruminants

Bacterial infections are the cause of many reproductive disorders of economic importance, such as mastitis, in livestock. Unfortunately, very little is known about the microbiota and the changes occurring during an infection state in small ruminants. The sequencing of regions of the 16S rRNA gene, is the useful tool to describe the whole dairy microbiome. Using this technique, studies have identified various phyla such as Firmicutes, Actinobacteria, Proteobacteria, Bacteroidetes, Fusobacteria and Cyanobacteria; and also several genera from raw milk of small ruminants. Nevertheless, there does not seem to be a consensus on the predominant genera nor phyla, even within the same breed. There is a lack of information about the mammary microflora in meat-oriented breeds, and about the microflora of colostrum and mastitis milk. Further studies comparing the microbiota between artificial and natural lactations and between healthy and mastitis milk are necessary. Considering the concerns arising from the use overuse of antibiotic therapy in Veterinary Medicine, it would be interesting to develop alternative strategies for the control of mastitis. Probiotics, such as lactic acid bacteria (LAB), have proven to be an interesting antibiotic-free strategy. Therefore, their presence in the dairy microflora of small ruminants and their interactions with other bacteria, such as mastitis-causing pathogens, should be scrutinized, given that the efficacy of probiotics increase when the bacterial strains used are specific to their host.

Tarkhineh as a new microencapsulation matrix improves the quality and sensory characteristics of probiotic Lactococcus lactis KUMS-T18 enriched potato chips

In the present study, probiotic potato chips containing a newly isolated probiotic Lactococcus lactis KUMS-T18 strain were produced by using a simple spraying method and then enhancing the stability, survival rate, and sensory characteristics of product during storage at 4 °C and 25 °C was examined for four months. Based on the results, Lactococcus lactis KUMS-T18 isolated from traditional Tarkhineh as a safe strain had high tolerance to low pH and high bile salt, anti-pathogenic activity, hydrophobicity, adhesion to human epithelial cells, auto- and co-aggregation, cholesterol assimilation and antibiotic susceptibility. Meanwhile, by micro-coating the probiotic cells in Tarkhineh formulations, elliptical to spherical shape (460-740 µm) probiotic drops were produced. The results revealed that potato chips produced with turmeric and plain Tarkhineh during storage at 4 °C, had excellent protection abilities for probiotic cells with about 4.52 and 3.46 log decreases in CFU/g respectively. On the other hand, probiotic potato chips, compared to non-probiotic and commercial potato chips, showed the criteria of probiotic products such as excellent quality and superior sensory characteristics. In summary, this study proved that probiotic Lactococcus lactis KUMS-T18 strain covered by Tarkhineh formulations as protective matrix has high potential to be used in the production of probiotic potato chips.

Application of Tarkhineh Fermented Product to Produce Potato Chips With Strong Probiotic Properties, High Shelf-Life, and Desirable Sensory Characteristics

The application of Tarkhineh texture to protect probiotics in potato chips has been investigated as the main goal in this paper. In this study, the probiotic assessments, morphological characteristics, sensory evaluation, and survival rates of the covered probiotic cells with Tarkhineh in potato chips during storage time were assessed. Based on results, T34 isolated from traditional Tarkhineh as a safe strain had a high tolerance to low pH and bile salt conditions, displayed acceptable anti-pathogenic activities, and also showed desirable antibiotic susceptibility. Two types of Tarkhineh formulations (plain Tarkhineh and turmeric Tarkhineh) were applied using a simple spraying method for covering T34 cells in potato chips. All formulations showed elliptical to spherical (480-770 μm) shape probiotic drops. Storage stability results revealed that T34 cells mixed with turmeric and plain Tarkhineh during 4 months of storage at 4°C displayed excellent protection abilities with about 3.70 and 2.85 log decreases in CFU/g respectively. Additionally, probiotic potato chips compared to non-probiotic and commercial potato chips, exhibited probiotic product criteria such as excellent quality and superior sensory properties during storage time. In conclusion, Tarkhineh showed high potential as a protective matrix for probiotic cells in potato chips.

Ready to Use Therapeutical Beverages: Focus on Functional Beverages Containing Probiotics, Prebiotics and Synbiotics

The growing global interest in functional foods containing nutrients capable of adding possible beneficial health effects is rapidly increasing both interest and consumer demand. In particular, functionalized beverages for their potential positive effect on health e.g., decreasing cholesterol level, lowering sugar, high fiber content, ability to enhance the immune system, and help digestion, have recently received special attention. Among the different beverages available on the market, probiotic dairy and non-dairy products have attracted much attention because of their affordable cost and their numerous therapeutic activities. Fermented milk and yogurt are currently worth €46 billion, with 77% of the market reported in Europe, North America, and Asia. Consumption of dairy beverages has some limitations due for example to lactose intolerance and allergy to milk proteins, thereby leading consumers to use non-dairy beverages such as fruit, grains, and vegetable juices to add probiotics to diet as well as driving the manufacturers to food matrices-based beverages containing probiotic cultures. The purpose of this review article is to evaluate the therapeutic performance and properties of dairy and non-dairy beverages in terms of probiotic, prebiotic, and synbiotic activities.

Effect of milk types on the attributes of a glutinous rice wine-fermented yogurt-like product

This study was conducted to analyze the effect of milk types on the attributes of the glutinous rice wine-fermented yogurt-like product named Kouwan Lao (KWL). Four types of raw milks were used in this study, including high temperature, long time (HTLT: H milk), HTLT milk supplemented with 3% skim milk powder (S milk), pasteurized milk (P milk), and ultra-high temperature milk (U milk). Microbiological compositions of the fermented glutinous rice and KWL at different stages were analyzed using PCR-denaturing gradient gel electrophoresis and gene sequencing based on 16S rRNA and 26S rRNA. The physicochemical properties of KWL samples were determined, and textural properties of those were analyzed using a texture analyzer (Jiawei Innovation and Technology Co. Ltd., Zhejiang Province, China). The microstructure of KWL samples was observed using scanning electron microscopy. The results showed that the milk types had significant influences on the bacterial composition of KWL. In the curdling process, the predominant bacteria of H, S, P, and U KWL samples were Lactobacillus brevis, Janthinobacterium sp., Lactobacillus casei, and Streptococcus agalactiae, respectively. In the ripening process, the main strains in H KWL were Enterococcus faecium and Pediococcus pentosaceus. Lactobacillus casei and Lactobacillus paracasei were the dominant bacteria of U KWL. Lactobacillus casei was the main strain of P KWL, and no bacteria were detected in S KWL. Saccharomyces cerevisiae was the dominant fungus of KWL, and no significant effect of milk types on fungal composition of KWL was found. The results of physicochemical properties showed that significant differences in protein contents were found in the KWL samples, and P KWL had the highest protein content. The fat content of U KWL was significantly higher than that of samples from the other 3 groups. The U KWL and P KWL showed lower moisture than that of the other 2 KWL samples. In addition, no significant difference in pH value was found in all samples. The results of texture analysis and microstructure showed that compared with other 3 types of KWL samples, the related mass parameters of U KWL were more advantageous and improved significantly with the increase of the heat treatment temperature of raw milk and the addition of skim milk powder. Our findings revealed the effects of milk types on microbial composition, physicochemical properties, textural properties, and microstructure of KWL, and provided a basic theory for the optimization and industrial production of KWL.

Molecular Identification and Probiotic Potential Characterization of Lactic Acid Bacteria Isolated from Human Vaginal Microbiota

Purpose: The increased demand for probiotics because of their health purposes provides the context for this study, which involves the molecular identification of lactic acid bacteria (LAB) obtained from the vaginal microbiota of healthy fertile women. The isolates were subjected for examination to prove their probiotic potential. In particular, the isolates were subjected to various tests, including acid/bile tolerance, antimicrobial activity, antibiotic susceptibility, Gram staining, and catalase enzyme activity assessment. Methods: Several methods were utilized for the molecular identification of the isolates, including ARDRA, (GTG)5-PCR fingerprinting, and the PCR sequencing of 16S-rDNA amplified fragments. Disc diffusion and well diffusion methods were used to assess antibiotic susceptibility and antibacterial activity of isolates. Tolerance to acid and bile was performed at pH 2.5 and 0.3% bile oxgall. Results: A total of 45 isolates of 88 separate organisms was selected. All of the isolates demonstrated an antibacterial effect on the exploited indicator microorganisms. All selected strains also maintained their viability at low-pH and high-bile salt conditions and exhibited abroad variation in their survival. Only the Enterococcus avium strain showed resistance to all 9 tested antibiotics. Based on the molecular identification and clustering, the 45 isolated bacteria were classified into three major groups of LAB: Enterococcus, Lactobacillus and Lactococcus. Conclusion: LAB are microorganisms that have a particularly important function in maintaining the health of the vaginal and gastrointestinal tract and in protecting it from infection by other pathogenic organisms. The isolates found to be a promising probiotic candidate by showed desirable characteristics. Therefore, strain DL3 can be used as natural food preservative with some more potential investigations.

The Inhibition Effect of Lactobacilli Against Growth and Biofilm Formation of Pseudomonas aeruginosa

The emergence of antibiotic-resistant and food-spoilage microorganisms has renewed efforts to identify safe and natural alternative agents of antibiotics such as probiotics. The aim of this study was the isolation of lactobacilli as potential probiotics from local dairy products with broad antibacterial and anti-biofilm activities against antibiotic-resistant strains of Pseudomonas aeruginosa and determination of their inhibition mechanism. Antibiotic susceptibility and classification of acquired resistance profiles of 80 P. aeruginosa strains were determined based on Centers for Disease Control and Prevention (CDC) new definition as multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan-drug-resistant (PDR) followed by antibacterial assessment of lactobacilli against them by different methods. Among the 80 P. aeruginosa strains, 1 (1.3%), 50 (62.5%), and 78 (97.5%) were PDR, XDR, and MDR, respectively, and effective antibiotics against them were fosfomycin and polymyxins. Among 57 isolated lactobacillus strains, two strains which were identified as Lactobacillus fermentum using biochemical and 16S rDNA methods showed broad inhibition/killing and anti-biofilm effects against all P. aeruginosa strains. They formed strong biofilms and had bile salts and low pH tolerance. Although investigation of inhibition mechanism of these strains showed no bacteriocin production, results obtained by high-performance liquid chromatography (HPLC) analysis indicated that their inhibitory effect was the result of production of three main organic acids including lactic acid, acetic acid, and formic acid. Considering the broad activity of these two L. fermentum strains, they can potentially be used in bio-control of drug-resistant strains of P. aeruginosa.

Anti-proliferative, pro-apoptotic and anti-oxidative activity of Lactobacillus and Bifidobacterium strains: A review of mechanisms and therapeutic perspectives

Lactobacillus and Bifidobacterium strains, their isolated constituents and substances that they secrete exert various anti-cancer actions, resulting from their anti-proliferative, pro-apoptotic and anti-oxidant properties. They can express and secrete anti-oxidant enzymes, bind reactive oxygen species, release small molecular weight anti-oxidants and chelate transition metals, preventing detrimental actions of many carcinogens. Lactobacillus and Bifidobacterium can interact with proteins regulating the cell cycle inhibiting proliferation of cancer cells, which often are intrinsically resistant to apoptosis. Lactobacilli and bifidobacteria can break this resistance through activation of pro-caspases and downregulation of the anti-apoptotic Bcl-2 and upregulation of pro-apoptotic Bax proteins. Anti-cancer effects of these bacteria can be also associated with their multi-pathways action in the microbiota. However, exact mechanism of their anti-cancer action is poorly known and needs further studies, which are justified by the important role of these bacteria in cancer biology as well as their potential preventive and therapeutic use.

Evaluation of probiotic Lactobacillus plantarum against foodborne pathogens and its fermentation potential in improving Lolium multiflorum silage quality

The objective of this study was to isolate the lactic acid bacteria from fermented silage sample and analyze their antibacterial activities, probiotic properties, and fermentation potential in silage. Eleven lactic acid bacteria (LAB) were selected based on distinct morphologies and preliminary studies. Cell-free supernatant (CFS) was then prepared from the selected strains for antibacterial analysis. L-30 strain and its CFS showed highest inhibition (> 10 mm) against tested foodborne pathogens as compared to other strains. Hereafter, the strain L-30 was named as KCC-30 and used for further studies. KCC-30 can survive in the harsh conditions of GIT such as low pH ( 2) and bile salt environment (oxgal) than standard L. plantarum KACC-91016 (pH 2: 27.2% vs 20.5%; oxgal: 72.3% vs 57.7%, both p < 0.05). In addition, KCC-30 exhibited strong auto-aggregation (68.3% vs 51.5%) and co-aggregation (33% vs 23.9%) properties. For silage experiment, KCC-30 treatment did not alter the nutrient profiles of silage. At the same time, KCC-30 treatment increased the lactic acid content of silage as compared to untreated silage (5.55 DM% vs 3.11 DM%). An increase of lactic acid content in the silage is due to higher lactic acid bacteria population in KCC-30 treated silage (15.33 × 10⁷ CFU/g vs 7.66 × 10⁷ CFU/g) than untreated silage (p < 0.05). Overall data suggested that KCC-30 exhibited strong probiotic potential and improved the quality of Lolium multiflorum silage by increasing the lactic acid level. Therefore, KCC-30 could be considered as potential strain to improve the fermentation quality of L. multiflorum silage.

Probiotic potentials of Lactobacillus plantarum isolated from fermented durian (Tempoyak), a Malaysian traditional condiment

Lactic acid bacterium isolated from fermented durian (tempoyak) was investigated for its potentials as a probiotic strain. Bacterial tolerance toward gastrointestinal environment, adhesion, and cytotoxic activity in human colon adenocarcinoma cell line HT-29 was evaluated. 16S rRNA sequencing identified the lactic acid bacterium as Lactobacillus plantarum. The bacterium demonstrated good tolerance toward gastrointestinal pH 2.0 and 0.3% bile salts. It showed strong adhesive capacity in human intestinal cell line, HT-29, with an adhesion index of 159 ± 10. Cytotoxicity of L. plantarum was investigated using both live bacterial cells (BC) and cell-free supernatant (CFS). Findings showed that both BC and CFS of L. plantarum reduced proliferation of HT-29 colon adenocarcinoma cells using MTT assay. The results imply potential probiotic properties of L. plantarum isolated from tempoyak.

Proteinaceous Secretory Metabolites of Probiotic Human Commensal Enterococcus hirae 20c, E. faecium 12a and L12b as Antiproliferative Agents Against Cancer Cell Lines

Cancer is the second leading cause of death worldwide and its incidence is expected to grow by almost 70% in the coming 2 decades. Recent microbiome studies in cancer mice models have shown that certain commensal bacteria play protective roles against cancer. Thus, the use of commensal microflora having anticancer activities for the treatment of cancer appears to be an attractive alternative therapeutic strategy. Lactic acid bacteria (LAB) form an integral component of commensal microflora in healthy individuals. As the vaginal ecosystem is enriched in LAB genera, we screened the vaginal LAB microflora of healthy women for their anti-proliferative abilities against various human cancer cell lines. The secreted metabolites of three enterococcal strains, Enterococcus hirae 20c, Enterococcus faecium 12a and L12b, out of 92 LAB isolates selectively inhibited the in vitro proliferation of various human cancer cell lines in a dose-dependent manner but had no activity against normal human peripheral blood monocytes. Further, proteinase K-treatment of the cell-free supernatant (CS) of all the three enterococci abrogated their anti-proliferative abilities, thereby showing the proteinaceous nature of the secreted metabolites in the CS. The microscopic examination of the cell lines showed that CS-treatment induced apoptosis-like morphological changes in the cancer cells. Further, the probiotic characters of the strains were studied, which showed that all the three strains had broad spectrum antimicrobial activities against various Gram-positive and Gram-negative pathogens, including Mycobacterium smegmatis. All the strains tolerated the gastric acidity and bile juice treatments, and had strong adhesive abilities to the colonic epithelial cell line HCT-15. Furthermore, none of the strains had any known secreted virulence factors or harbored virulence genes. This preliminary study highlights an important functional role of the commensal probiotic enterococcal strains E. hirae and E. faecium for the first time by demonstrating their anticancer properties that should be further tested in the in vivo mammalian models.

Probiotics and Disease: A Comprehensive Summary-Part 9, Cancer

This article provides a literature review of the disease-specific probiotic strains associated with cancer. The literature review was restricted to research in both humans and animals. This is not an exhaustive review. The table design allows for quick access to supportive data and will be helpful as a guide for both researchers and clinicians. The goal of the probiotics and disease series is to provide clinically useful tools. The first article part 1 focused on mental health and neurological conditions; the second article part 2 explored cultured and fermented foods that are commonly available in the United States; part 3 explored the relationship between bacterial strains and 2 of the most prevalent diseases we have in modern society: cardiometabolic disease and fatigue syndromes; part 4 elucidated the role of the microbiome in infectious diseases; part 5 explored respiratory conditions of the ears, nose, and throat; part 6 explored the relationship between microbiota and skin disorders; part 7 reviewed allergy and autoimmune disease; and part 8 examined gastrointestinal and genitourinary conditions. This ninth article reviews the relationship between microbiota and cancer development and prognosis. This literature review is specific to disease condition, probiotic classification, and individual strain.

Isolation and characterization of probiotics from dairies

BACKGROUND AND OBJECTIVES

Probiotics are live microorganisms, which show beneficial health effects on hosts once consumed in sufficient amounts. LAB group can be isolated and characterized from traditional dairy sources. This study aimed at isolating, identifying, and in vitro characterizing (low pH/high bile salt tolerance, antibacterial activity, and antibiotic susceptibility) LAB strains from traditional Iranian dairy products.

MATERIALS AND METHODS

Isolated strains were identified by Gram staining, catalase assay, and 3 molecular identification methods; namely, (GTG) 5-PCR fingerprinting, ARDRA, and 16S rDNA gene sequencing.

RESULTS

A total of 19 LAB strains belonging to 4 genera (Lactococcus, Leuconostoc, Lactobacillus and Enterococcus) were identified.

CONCLUSION

The experiments revealed that L. plantarum 15HN, L. lactis subsp. cremoris 44L and E. mundtii 50H strains, which were isolated from shiraz, cheese and shiraz, respectively, displayed a desirable tolerance to low pH and high bile salts, favorable anti-pathogen activity, and acceptable antibiotic susceptibility; hence, they could be considered as novel probiotic candidates and applied in the food industry.

Capacity of lactic acid bacteria in immunity enhancement and cancer prevention

Lactic acid bacteria are associated with the human gastrointestinal tract. They are important for maintaining the balance of microflora in the human gut. An increasing number of published research reports in recent years have denoted the importance of producing interferon-gamma and IgA for treatment of disease. These agents can enhance the specific and nonspecific immune systems that are dependent on specific bacterial strains. The mechanisms of these effects were revealed in this investigation, where the cell walls of these bacteria were modulated by the cytokine pathways, while the whole bacterial cell mediated the host cell immune system and regulated the production of tumor necrosis factors and interleukins. A supplement of highly active lactic acid bacteria strains provided significant potential to enhance host's immunity, offering prevention from many diseases including some cancers. This review summarizes the current understanding of the function of lactic acid bacteria immunity enhancement and cancer prevention.

Probiotic Assessment of Lactobacillus plantarum 15HN and Enterococcus mundtii 50H Isolated from Traditional Dairies Microbiota

PURPOSE

Probiotics are microorganisms, which show beneficial health effects on hosts once consumed in sufficient amounts. Among probiotic bacteria, the bioactive compounds from lactic acid bacteria (LAB) group can be utilized as preservative agents. LAB group can be isolated and characterized from traditional dairy sources. This study aimed to isolate, identify, and biologically characterize probiotic LAB strains from Iranian traditional dairy products.

METHODS

A total of 19 LAB strains were identified by sequencing of their 16S rRNA genes. They were examined for adherence to human intestinal Caco-2 cells and tolerance to low pH/high bile salts and simulated in vitro digestion conditions. Moreover, they were evaluated further to assess their ability to prevent the adhesion of Escherichia coli 026 to the intestinal mucosa, inhibitory functions against pathogens, and sensitivity to conventional antibiotics.

RESULTS

L. plantarum 15HN and E. mundtii 50H strains displayed ≥ 71% survival rates at low pH/high bile salts and ≥ 40% survival rates in digestive conditions. Their adherences to Caco-2 cells were 3.2×105 and 2.6×105 CFU mL-1 respectively and high values of anti-adhesion capability were observed (≥36%). They inhibited the growth of 13 and 11 indicator pathogens respectively. Moreover, they were sensitive or semi-sensitive to seven and three out of eight antibiotics respectively.

CONCLUSION

L. plantarum 15HN and E. mundtii 50H, which were isolated from shiraz product, displayed above-average results for all of the criteria. Therefore, they can be introduced as novel candidate probiotics that could be used in the food industry.

Probiotic Assessment of Lactobacillus plantarum 15HN and Enterococcus mundtii 50H Isolated from Traditional Dairies Microbiota

PURPOSE

Probiotics are microorganisms, which show beneficial health effects on hosts once consumed in sufficient amounts. Among probiotic bacteria, the bioactive compounds from lactic acid bacteria (LAB) group can be utilized as preservative agents. LAB group can be isolated and characterized from traditional dairy sources. This study aimed to isolate, identify, and biologically characterize probiotic LAB strains from Iranian traditional dairy products.

METHODS

A total of 19 LAB strains were identified by sequencing of their 16S rRNA genes. They were examined for adherence to human intestinal Caco-2 cells and tolerance to low pH/high bile salts and simulated in vitro digestion conditions. Moreover, they were evaluated further to assess their ability to prevent the adhesion of Escherichia coli 026 to the intestinal mucosa, inhibitory functions against pathogens, and sensitivity to conventional antibiotics.

RESULTS

L. plantarum 15HN and E. mundtii 50H strains displayed ≥ 71% survival rates at low pH/high bile salts and ≥ 40% survival rates in digestive conditions. Their adherences to Caco-2 cells were 3.2×105 and 2.6×105 CFU mL-1 respectively and high values of anti-adhesion capability were observed (≥36%). They inhibited the growth of 13 and 11 indicator pathogens respectively. Moreover, they were sensitive or semi-sensitive to seven and three out of eight antibiotics respectively.

CONCLUSION

L. plantarum 15HN and E. mundtii 50H, which were isolated from shiraz product, displayed above-average results for all of the criteria. Therefore, they can be introduced as novel candidate probiotics that could be used in the food industry.