In vitroevaluation ofPediococcus acidilacticiNCDC 252 for its probiotic attributes

Effect of Pediococcus acidilactici and mango seed polyphenols on the fermentative profile of the indigestible fraction of yam bean

Yam bean is an important source of dietary fiber and other components that comprise the total indigestible fraction (TIF), which can be fermented by the colonic microbiota and produce metabolites with beneficial health effects. Therefore, the objective of this study was to evaluate the in vitro colonic fermentation of yam bean TIF and the changes caused by the addition of a polyphenolic extract of mango seed and the lactic acid bacteria Pediococcus acidilactici. The mango seed extract was obtained by ultrasound-assisted extraction, and the microbial growth rate and viability of P. acidilactici were determined using a Neubauer chamber. Yam bean TIF was isolated by triple enzymatic hydrolysis and subjected to in vitro colonic fermentation in combination with treatments with mango seed extract and P. acidilactici suspensions. Changes in pH, total soluble phenols (TSP), and antioxidant capacity (AOX) were evaluated. Furthermore, the production of metabolites was quantified by HPLC-DAD-MS and GC-MS. The Growth rate of P. acidilactici was 0.1097 h-1 with 97.5 % viability at 7 h of incubation. All TIF treatments showed a high capacity of fermentation, and the addition of mango seed extract increased the TSP content and AOX in DPPH and FRAP assays. A total of Forty-six volatile metabolites were detected, with highlighting the presence of esters, benzenes, aldehydes, and short-chain fatty acids. Five phenolic compounds associated with mango by-products were quantified during all fermentation process, despite the concentration of the extract. P. acidilactici did not substantially modify the fermentative profile of TIF. However, further studies such as the evaluation of the abundance of microbial communities may be necessary to observe whether it can generate changes during colonic fermentation.

Probiotic Pediococcus acidilactici strain from tomato pickle displays anti-cancer activity and alleviates gut inflammation in-vitro

The present study characterized the potential probiotic properties of Pediococcus acidilactici TMAB26 strain isolated from traditional Indian tomato pickle, and evaluated its possible therapeutic applications as an anti-cancer and anti-inflammatory agent in vitro. The 16S rRNA sequencing and primary screening demarcated TMAB26 strain as an ideal probiotic candidate, with distinctive properties of acid tolerance (58.02% at pH 2.5), bile tolerance (55.53% at 0.5%), and efficient adherence to the mucosal surface of the human intestinal cells in vitro, along with antagonistic, anti-inflammatory, and anti-cancer properties. The strain exhibited antagonism against standard intestinal pathogenic strains Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, E. coli, Klebsiella pneumonia, and Salmonella typhi with zones of inhibition in the range of 6-18 mm. The cytotoxicity evaluation of the probiotic isolate TMAB26 culture supernatant (1:1 dilution) showed significant cytotoxicity on HT-29 (94.91% ± 1.27) and Caco-2 (92.63% ± 0.63) cancer cells when compared to that of the peripheral blood mononuclear cells (PBMCs) alone. Furthermore, the strain culture supernatant reduced the mRNA levels of the proinflammatory cytokine tumor necrosis factor-alpha (TNF-α) by threefold, Interleukin-6 (IL-6) by eightfold and increased the mRNA levels of the anti-inflammatory cytokine Interleukin-10 (IL-10) in lipopolysaccharide (LPS) pretreated HT-29 and peripheral blood mononuclear cells (PBMCs), suggesting the potential role of TMAB26 isolate, i.e., Pediococcus acidilactici MTCC 13014 in alleviating gut inflammation.

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The online version contains supplementary material available at 10.1007/s13205-020-02570-1.

Next generation sequencing, biochemical characterization, metabolic pathway analysis of novel probiotic Pediococcus acidilactici NCDC 252 and it's evolutionary relationship with other lactic acid bacteria

Pediococcus acidilactici NCDC 252 is a facultative anaerobe of dairy origin that possessed all studied in vitro probiotic attributes and several useful enzyme activities. Its whole genome was sequenced and analysed for its evolutionary relationship with other lactic acid bacteria (LAB). This is a novel sequence and first report of genome sequence of P. acidilactici of dairy origin. Its genome is relatively larger than other studied genomes of P. acidilactici and is comprised of 40 scaffolds that totals to 3,243,337 bases and 44.5% GC content. A total of 3054 coding sequences (CDS) were identified by RAST and DIAMOND servers. The genome also encoded different enzyme activities required for utilization of various carbohydrates. This was also confirmed by carbohydrate utilization studies. The genome also encoded genes for probiotics properties. The phylogenetic analysis of P. acidilactici NCDC 252 genome was done using Maximum Parsimony and Maximum Likelihood methods to study its evolution and relatedness to other LABs based upon their 16S rDNA sequences. The strain exhibited highest resemblance to Lactobacillus plantarum WCFS1 and is also much close to P. acidilactici based on similarity of ribosomal protein. The strain seems to have acquired some genes for its adaptation in dairy/environmental niche. This genome sequence is novel with genome more similar to L. plantarum and biochemical and phenotypic characteristics of P. acidilactici.

Purification, kinetic and functional characterization of membrane bound dipeptidyl peptidase-III from NCDC 252: a probiotic lactic acid bacteria

Pediococcus acidilactici is a probiotic lactic acid bacteria possessing studied in-vitro probiotic properties. Study of membrane proteins is crucial in developing technological and health applications of probiotic bacteria. Genome analysis of Pediococcus acidilactici revealed about more than 60 proteases/peptidases which need characterization. Dipeptidyl peptidase-III (DPP-III) is studied for first time in prokaryotes and it is a membrane protein in P. acidilactici that has been purified to apparent homogeneity. The enzyme was purified 81.66 fold with 36.75% yield. The specific activity of purified DPP-III was 202.67 U/mg. The protein moved as single band on native PAGE. The purity was also confirmed by in-situ gel assay. However SDS-PAGE analysis revealed it as high molecular weight heterotetramer with molecular weight of 108 kDa. The enzyme was maximally active at pH 8.5 and at 37 C. Purified DPP-III specifically hydrolyzed Arg-Arg-4-βNA with micromolar affinity (K_m = 9.0 µM) and none of studied endopeptidase and monopeptidase substrate was hydrolyzed. Inhibition study revealed purified DPP-III to be a serine protease with involvement of metal ion at active site. The significance of this enzyme as membrane protein is yet to be studied.

Effect of sodium selenite on the bacteria growth, selenium accumulation, and selenium biotransformation in Pediococcus acidilactici

In this study, the effect of low selenium concentrations on bacteria growth, selenium bioaccumulation, and selenium speciation in Pediococcus acidilactici was investigated. Six different sodium selenite (Na₂SeO₃) solutions with concentrations of 0, 0.5, 1, 2, 3, and 4 mg/L were added in MRS broth for 24 h. Then, the obtained bacterial pellets were weighed. The contents of total selenium and selenium species in the bacterial pellets were measured via optimized enzymatic hydrolysis and HPLC-ICP-MS. The maximum dried P. acidilactici biomass of 1.44 g/L was achieved by utilizing 1 mg/L Na₂SeO₃. By increasing sodium selenite concentrations, total selenium contents were significantly increased from 0.14 to 1.45 mg/g dry weight (p < 0.05). The findings indicated that selenium was favorably incorporated into the bacteria protein fraction and mainly formed selenocysteine. Therefore, selenium-enriched lactic acid bacterium P. acidilactici can deliver a less-toxic, more bioavailable selenium source for human and animal nutrition.

Mechanistic Insight of Probiotics Derived Anticancer Pharmaceuticals: A Road Forward for Cancer Therapeutics

Probiotics are living organisms that confer health benefits when administered in adequate amounts. Probiotics are continuously being explored for their different health beneficiary activities. Anticancer activity is one of the most important benefits both from a preventive and therapeutic point of view. Though not many studies have been conducted to date in this area, a number suggest using laboratory animal models and different cell lines that there may be a mechanistic basis for the anticancer effects of probiotics and require more scientific justification and clinical trials. Most studies of probiotics are conducted for colon cancer associated with inflammatory bowel disease. Studies are also being extended to other types of cancer in different cell lines. This review summarizes studied probiotics considered for treatment of colon cancer and some other cancers (in cancer cell lines) and also proposed mechanism how probiotics are inhibiting cancer growth along with some challenges and future perspectives.

Dipeptidyl peptidase-II from probiotic Pediococcus acidilactici: Purification and functional characterization

Dipeptidylpeptidase-II (DPP-II, E.C. 3.4.14.2), an exopeptidase was purified 15.4 fold with specific activity and yield of 15.4U/mg/mL and 14.68% respectively by a simple two step procedure from a probiotic Pediococcus acidilactici. DPP-II is 38.7KDa homodimeric serine peptidase with involvement of His and subunit mass of 18.9KDa. The enzyme exhibited optimal activity at pH 7.0 and 37°C with activation energy of 24.97kJ/mol. The enzyme retained more than 90% activity upto 50°C thus adding industrial importance. DPP-II hydrolysed Lys-Ala-4mβNA with K_M of 50μM and V_max of 30.8nmol/mL/min. In-silico characterization studies of DPP-II on the basis of peptide fragments obtained by MALDI-TOF revealed an evolutionary relationship between DPP-II of prokaryotes and phosphate binding proteins. Secondary and three-dimensional structure of enzyme was also deduced by in-silico approach. Functional studies of DPP-II by TLC and HPLC-analysis of collagen degraded products revealed that enzyme action released free amino acids and other metabolites. Microscopic and SDS-PAGE analysis of enzyme treated analysis of chicken's chest muscle (meat) hydrolysis revealed change and hydrolysis of myofibrils. This may affect the flavor and texture of meat thereby suggesting its role in meat tenderization. Being a protein of LAB (Lactic acid bacteria), it is also expected to be safe.