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•Strains from LAB can accumulate and biotransform sodium selenite from growth medium.•First description of Se produced by Lactococcus lactis subsp. cremoris.•LAB transforms Se into ...selenocysteine and nanoparticles.•Se-enriched LAB can be used to develop new functional foods for humans.
In the present study, we evaluated the ability of inorganic Se to accumulate and biotransform into different selenium species and Se nanoparticles (SeNPs) in seven bacteria from the Lactococcus, Streptococcus, and Enterococcus genera. The cytotoxicity of selenized strains to human adenocarcinoma Caco-2 and HT29 cells, the effect of selenium enrichment on antioxidant activity, and cell surface hydrophobicity of the tested strains were determined. When compared to that of lactococci and enterococci, increasing concentrations of sodium selenite in the cultivation media inhibited the growth of Streptococcus thermophilus strains. Thirty milligrams per liter Na2SeO3 and its higher concentrations (50 and 100 mg/L) significantly reduced the viability of Caco-2 and HT29 cells by 40–75%. Bacteria mainly produced SeNPs and selenocysteine in Se form. Our results indicate that the tested strains can accumulate and transform inorganic selenium, which makes them promising candidates for selenization and possible application in functional foods.
The unicellular green microalga
is a potential source of a wide range of nutritionally important compounds applicable to the food industry. The aim of this study was to assess the effect of
dried ...biomass on the growth and adherence of 10 strains of
,
and
. The immunomodulatory, antioxidant, and cytotoxic effects of
on human peripheral mononuclear cells and simulated intestinal epithelial cell lines Caco-2 and HT-29 were evaluated. Furthermore, the hypocholesterolemic effects of the microalgae on lipid metabolism in rats fed a high-fat diet were analyzed. The addition of
biomass had a positive effect on the growth of nine out of 10 probiotics and promoted the adherence of three bifidobacteria strains to human cell lines. The antioxidant and immunomodulatory properties of
were concentration-dependent. The inflammatory cytokines (TNF-α and IL-6) were significantly increased following
stimulation at the lowest concentration (0.5%
). Eight week supplementation of
to the diet of hypercholesteromic rats significantly decreased the serum concentrations of LDL-C, VLDL, IDL-B, and IDL-C.
is not cytotoxic in intestinal cell models; it promotes adherence of selected bifidobacteria, it affords immunomodulatory and antioxidant effects, and its addition to diets may help decrease atherosclerosis risk factors.
Selenized lactic acid bacteria (LAB) represent potentially safe and effective sources of selenium (Se), essential for human health, as lactic acid fermentation improves Se bioavailability and reduces ...its toxicity. LAB are generally recognized as safe (GRAS) and widely used in fermented dairy products. To facilitate selenized LAB implementation as a functional food, we developed and characterized new Se-enriched strains based on the food industry commercial strains Streptococcus thermophilus CCDM 144 and Enterococcus faecium CCDM 922A as representatives of two LAB genera. We evaluated Se bioaccumulation capacity, Se biotransformation and growth ability in the presence of different sodium selenite concentrations (0–50 mg/L), and antioxidant properties (2, 2-diphenyl-1-picrylhydrazyl (DPPH) method) and cell surface hydrophobicity between Se-enriched and parental strains in vitro. Sodium selenite addition did not negatively influence growth of either strain; thus, 50 mg/L was chosen as the optimal concentration based on strain accumulation capacity. Selenization improved the antioxidant properties of both strains and significantly increased their cell surface hydrophobicity (p < 0.05). To our knowledge, this represents the first report of Se-enriched strain hydrophobicity as well as the first on Se speciation in families Enterococcaceae and Streptococcaceae. Moreover, both tested strains demonstrated good potential for Se-enrichment, providing a foundation for further in vitro and in vivo studies to confirm the suitability of these Se-enriched strains for industrial applications.
The selenium (Se) enrichment of yeasts and lactic acid bacteria (LAB) has recently emerged as a novel concept; the individual health effects of these beneficial microorganisms are combined by ...supplying the essential micronutrient Se in a more bioavailable and less toxic form. This study investigated the bioavailability of Se in the strains
CCDM 922A (EF) and
CCDM 144 (ST) and their respective Se-enriched forms, SeEF and SeST, in a CD (SD-Sprague Dawley) IGS rat model. Se-enriched LAB administration resulted in higher Se concentrations in the liver and kidneys of rats, where selenocystine was the prevalent Se species. The administration of both Se-enriched strains improved the antioxidant status of the animals. The effect of the diet was more pronounced in the heart tissue, where a lower glutathione reductase content was observed, irrespective of the Se fortification in LAB. Interestingly, rats fed diets with EF and SeEF had higher glutathione reductase activity. Reduced concentrations of serum malondialdehyde were noted following Se supplementation. Diets containing Se-enriched strains showed no macroscopic effects on the liver, kidneys, heart, and brain and had no apparent influence on the basic parameters of the lipid metabolism. Both the strains tested herein showed potential for further applications as promising sources of organically bound Se and Se nanoparticles.
Infant feces and breast milk are sources of lactic acid bacteria with interesting functional and technological properties. Therefore, we focused on the isolation and characterization of new potential ...probiotic strains from infant feces and breast milk. Nine strains were identified based on 16S rRNA sequences of Lacticaseibacillus rhamnosus, Limosilactobacillus reuteri, and Lactobacillus gasseri. Subsequently, these isolates were evaluated for their safety (antibiotic resistance, hemolytic, and enzymatic activity) and functional properties (gastrointestinal condition tolerance, hydrophobicity, auto-aggregation, adhesion to Caco-2/HT-29 cell lines, antimicrobial and antioxidant properties, and the production of exopolysaccharides). All the isolates were non-hemolytic and resistant to streptomycin, kanamycin, and vancomycin. They also demonstrated antimicrobial activity against five selected pathogens (Staphylococcus aureus, Bacillus cereus, Escherichia coli, Salmonella sp., and Enterococcus faecalis) and the production of exopolysaccharides. Isolates Lacticaseibacillus rhamnosus S1F and S6C together with Lactobacillus gasseri M8C showed the highest ability to survive 3.0 g/L of bile salts and a good adhesion property, which is important for gastrointestinal tract (GIT) colonization or the inhibition of pathogens. Following in vivo characterization, three strains S1F and S6C from infant feces, and M6C from breast milk, showed probiotic properties with potential applications in the food industry.
Current studies indicate a link between the intake of exclusive enteral nutrition (EEN) and the induction of complex changes in the intestinal microbiota, as well as the clinical improvement of ...Crohn's disease (CD). The first aim of this study was to test the ability of various commensal bacterial strains (
= 19) such as bifidobacteria, lactobacilli, and
to grow on three different polymeric EN
. Tested EN formulas were found to be suitable growth media for tested commensals. Furthermore, the counts of these bacteria and total counts of anaerobic bacteria in the fecal samples of children with CD (
= 15) before and after 6 weeks of EEN diet administration were determined using cultivation on selective media. The counts of cultivable commensal bacteria in the fecal samples of CD children were not significantly affected by EEN. However, tested bacteria showed some individual shifts in counts before and after EEN therapy. Moreover, cultured bifidobacteria were found to be in reduced counts in CD children. Therefore, the application of bifidogenic prebiotic compounds to EN for CD patients might be considered.
In this study, we tested the ability of lactobacilli and bifidobacteria strains to accumulate and biotransform sodium selenite into various selenium species, including selenium nanoparticles (SeNPs). ...Selenium tolerance and cytotoxicity of selenized strains towards human adenocarcinoma Caco-2 and HT29 cells were determined for all tested strains. Furthermore, the influence of selenium enrichment on the antioxidant activity of selenized strains and hydrophobicity of the bacterial cell surfaces were evaluated. Both hydrophobicity and antioxidant activity increased significantly in the selenized
L. paracasei
strain and decreased significantly in the selenized
L. helveticus
strain. The concentrations of 5 and 10 mg/L Na
2
SeO
3
in the growth media were safer for Caco-2 and HT29 cell growth than higher concentrations. At higher concentrations (30, 50, and 100 mg/L), the cell viability was reduced. All the tested strains showed differences in antioxidant potential and hydrophobicity after selenium enrichment. In addition to selenocystine and selenomethionine, the tested bacterial strains produced significant amounts of SeNPs. Our results show that the tested bacterial strains can accumulate and biotransform inorganic selenium, which allows them to become a potential source of selenium.
The unicellular green microalga Dunaliella is a potential source of a wide range of nutritionally important compounds applicable to the food industry. The aim of this study was to assess the effect ...of Dunaliella salina dried biomass on the growth and adherence of 10 strains of Lactobacillus, Lacticaseibacillus, and Bifidobacterium. The immunomodulatory, antioxidant, and cytotoxic effects of D. salina on human peripheral mononuclear cells and simulated intestinal epithelial cell lines Caco-2 and HT-29 were evaluated. Furthermore, the hypocholesterolemic effects of the microalgae on lipid metabolism in rats fed a high-fat diet were analyzed. The addition of D. salina biomass had a positive effect on the growth of nine out of 10 probiotics and promoted the adherence of three bifidobacteria strains to human cell lines. The antioxidant and immunomodulatory properties of D. salina were concentration-dependent. The inflammatory cytokines (TNF-α and IL-6) were significantly increased following Dunaliella stimulation at the lowest concentration (0.5% w/v). Eight week supplementation of D. salina to the diet of hypercholesteromic rats significantly decreased the serum concentrations of LDL-C, VLDL, IDL-B, and IDL-C. D. salina is not cytotoxic in intestinal cell models; it promotes adherence of selected bifidobacteria, it affords immunomodulatory and antioxidant effects, and its addition to diets may help decrease atherosclerosis risk factors.
Yeasts have the remarkable capability to transform and integrate inorganic selenium into their cellular structures, thereby enhancing its bioavailability and reducing its toxicity. In recent years, ...yeasts have attracted attention as potential alternative sources of protein.
This study explores the selenium accumulation potential of two less explored yeast strains, namely the probiotic Saccharomyces boulardii CCDM 2020 and Pichia fermentas CCDM 2012, in comparison to the extensively studied Saccharomyces cerevisiae CCDM 272. Our investigation encompassed diverse stress conditions. Subsequently, the selenized yeasts were subjected to an INFOGEST gastrointestinal model. The adherence and hydrophobicity were determined with undigested cells
Stress conditions had an important role in influencing the quantity and size of selenium nanoparticles (SeNPs) generated by the tested yeasts. Remarkably, SeMet synthesis was limited to Pichia fermentas CCDM 2012 and S. boulardii CCDM 2020, with S. cerevisiae CCDM 272 not displaying SeMet production at all. Throughout the simulated gastrointestinal digestion, the most substantial release of SeCys2, SeMet, and SeNPs from the selenized yeasts occurred during the intestinal phase. Notably, exception was found in strain CCDM 272, where the majority of particles were released during the oral phase.
The utilization of both traditional and non-traditional selenized yeast types, harnessed for their noted functional attributes, holds potential for expanding the range of products available while enhancing their nutritional value and health benefits.
•Comprehensive characterization of non-traditional selenized yeasts: Saccharomyces boulardii CCDM 2020 and Pichia fermentas CCDM 2012.•Stress conditions inhibited SeMet production in S. cerevisiae CCDM 272.•Selenized yeasts displayed antimicrobial activity against Staphylococcus aureus and Escherichia coli.•Novel insight into the adherence of selenized yeasts to CaCo-2/HT29 cells and exposure to the INFOGEST gastrointestinal model presented for the first time in this study.
The ability of bacteria to adhere to the intestinal mucosa is a critical property necessary for the long-term colonization of the intestinal tract. This ability can be highly sensitive to the ...presence of prebiotics. However, limited data are available in this respect for beneficial bacteria such as probiotics or resident gut microbiota. We previously demonstrated that the presence of prebiotics may decrease adherence in several pre- and probiotic combinations. Thus, characterizing the interactions between numerous combinations involving different classes of pre- and probiotics can be crucial in identifying new synbiotics. Accordingly, here, we extend our prior analyses to evaluate the adhesion of five lactobacilli, six bifidobacteria, and one probiotic Escherichia coli strains, as commercial probiotics or promising probiotic candidates, together with the cariogenic Bifidobacterium dentium strain. As an in vitro intestinal mucosa model, Caco-2 and mucin-secreting HT29-MTX cells were co-cultured at 9:1 in the presence or absence of prebiotics. Commercial inulin-type fructooligosaccharide prebiotics Orafti® GR, Orafti® P95, and galactooligosaccharide-based prebiotic formula Vivinal®, including purified human milk oligosaccharides (HMOs) were added into the cultivation media as the sole sugar source (2.5% each). Adherence was tested using microtiter plates and was evaluated as the percentage of fluorescently labeled bacteria present in the wells after three washes. Consistent prebiotics-mediated enhanced adherence was observed only for the commercial probiotic strain E. coli O83. For the remaining strains, the presence of HMO or prebiotics Orafti® P95 or Orafti® GR decreased adherence, reaching statistical significance (p < 0.05) for three of out of eight (HMO) or five of out of 11 strains tested, respectively. Conversely, Vivinal® enhanced adhesion in six out of the 12 strains tested, and notably, it significantly attenuated the adherence of the cariogenic Bifidobacterium dentium Culture Collection of Dairy Microorganisms (CCDM) 318. To our knowledge, this represents the first report on the influence of commercial prebiotics and HMOs on the adhesion of the cariogenic Bifidobacterium sp. Vivinal® seems to be a promising prebiotic to be used in the formulation of synbiotics, supporting the adhesion of a wide range of probiotics, especially the strains B. bifidum BBV and BBM and the probiotic Escherichia coli O83.
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