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BMC Microbiology Jun 2022Probiotic starters can improve the flavor profile, texture, and health-promoting properties of fermented foods. Tetragenococcus halophilus is a halophilic lactic acid...
BACKGROUND
Probiotic starters can improve the flavor profile, texture, and health-promoting properties of fermented foods. Tetragenococcus halophilus is a halophilic lactic acid bacterium that is a candidate starter for high-salt fermented foods. However, the species is known to produce biogenic amines, which are associated with neurotoxicity. Here, we report a probiotic starter strain of T. halophilus, EFEL7002, that is suitable for use in high-salt fermentation.
RESULTS
EFEL7002 was isolated from Korean meju (fermented soybean) and identified as T. halophilus, with 99.85% similarity. The strain is safe for use in food as it is a non-hemolytic and non-biogenic amine producer. EFEL7002 is tolerant to gastrointestinal conditions and can adhere to Caco-2 cells. This strain showed antioxidant, anti-inflammatory, and protective effects against the human gut epithelial barrier. EFEL7002 grew well in media containing 0-18% NaCl showing maximum cell densities in 6% or 12% NaCl.
CONCLUSIONS
T. halophilus EFEL7002 can be used as a health-promoting probiotic starter culture for various salty fermented foods.
Topics: Biogenic Amines; Caco-2 Cells; Enterococcaceae; Fermentation; Food Microbiology; Humans; Probiotics; Republic of Korea; Sodium Chloride; Glycine max
PubMed: 35668352
DOI: 10.1186/s12866-022-02561-7 -
Applied and Environmental Microbiology Dec 2023is a halophilic lactic acid bacterium generally used as a starter culture in fermenting soy and fish sauces. Aggregating strains can be useful in fermenting and...
is a halophilic lactic acid bacterium generally used as a starter culture in fermenting soy and fish sauces. Aggregating strains can be useful in fermenting and obtaining clear soy sauce because cell clumps are trapped by the filter cake when the soy sauce mash is pressed. However, the genetic mechanisms of aggregation in are unknown. In this study, we identified genes encoding aggregation factor and its regulator. These findings may provide a foundation for developing improved starter cultures for soy sauce fermentation, leading to more efficient and consistent clear soy sauce production.
Topics: Animals; Enterococcaceae; Lactobacillales; Operon; Fermentation
PubMed: 38014957
DOI: 10.1128/aem.01458-23 -
Current Opinion in Microbiology Aug 2020Once overlooked as passive bystanders of the human intestinal microbiota, new evidence is shedding light on the importance of enterococci and their bacteriophages... (Review)
Review
Once overlooked as passive bystanders of the human intestinal microbiota, new evidence is shedding light on the importance of enterococci and their bacteriophages (phages) in shaping human health. Natural predators of enterococci, phages represent a narrow spectrum, precision targeting modality for the eradication of problematic enterococci within the microbiota or infected tissue. The identification of enterococcal phage receptors, absorption factors, and transcriptional responses following phage infection reveals a complex predator-prey relationship that modulates enterococcal cell surface architecture, susceptibility to antibiotics, and adaptation to host associated environments. Considering the dry up of contemporary antibiotic discovery pipelines in the pharmaceutical industry and a continued emergence of multidrug-resistant enterococci, enterococcal phages may serve as bonafide therapeutics. We highlight current advances in enterococcal phage biology with emphasis on recent breakthroughs in potential therapeutic applications that place enterococcal phages at the forefront of next-generation biologics.
Topics: Animals; Anti-Bacterial Agents; Bacteriophages; Drug Resistance, Bacterial; Enterococcus; Gram-Positive Bacterial Infections; Host-Pathogen Interactions; Humans; Phage Therapy
PubMed: 32652484
DOI: 10.1016/j.mib.2020.06.003 -
Infection and Immunity Oct 2021Second messenger nucleotides are produced by bacteria in response to environmental stimuli and play a major role in the regulation of processes associated with bacterial...
Second messenger nucleotides are produced by bacteria in response to environmental stimuli and play a major role in the regulation of processes associated with bacterial fitness, including but not limited to osmoregulation, envelope homeostasis, central metabolism, and biofilm formation. In this study, we uncovered the biological significance of c-di-AMP in the opportunistic pathogen Enterococcus faecalis by isolating and characterizing strains lacking genes responsible for c-di-AMP synthesis () and degradation ( and ). Using complementary approaches, we demonstrated that either complete loss of c-di-AMP (Δ strain) or c-di-AMP accumulation (Δ, Δ, and Δ Δ strains) drastically impaired general cell fitness and virulence of E. faecalis. In particular, the Δ strain was highly sensitive to envelope-targeting antibiotics, was unable to multiply and quickly lost viability in human serum or urine , and was virtually avirulent in an invertebrate (Galleria mellonella) and in two catheter-associated mouse infection models that recapitulate key aspects of enterococcal infections in humans. In addition to evidence linking these phenotypes to altered activity of metabolite and peptide transporters and inability to maintain osmobalance, we found that the attenuated virulence of the Δ strain also could be attributed to a defect in Ebp pilus production and activity that severely impaired biofilm formation under both and conditions. Collectively, these results demonstrate that c-di-AMP signaling is essential for E. faecalis pathogenesis and a desirable target for drug development.
Topics: Animals; Biofilms; Dinucleoside Phosphates; Enterococcus faecalis; Fimbriae, Bacterial; Gene Expression Regulation, Bacterial; Gram-Positive Bacterial Infections; Humans; Virulence
PubMed: 34424750
DOI: 10.1128/IAI.00365-21 -
Polish Journal of Microbiology 2010Pheromone-responsive plasmids constitute a unique group of approximately 20 plasmids identified, as yet, only among enterococcal species. Several of their... (Review)
Review
Pheromone-responsive plasmids constitute a unique group of approximately 20 plasmids identified, as yet, only among enterococcal species. Several of their representatives, e.g. pAD1, pCF10, pPD1 and pAM373 have been extensively studied. These plasmids possess a sophisticated conjugation mechanism based on response to sex pheromones--small peptides produced by plasmid-free recipient cells. Detailed analysis of regulation and function of the pheromone response process revealed its great complexity and dual role--in plasmid conjugation and modulation of enterococcal virulence. Among other functional modules identified in pheromone plasmids, the stabilization/partition systems play a crucial role in stable maintenance of the plasmid molecule in host bacteria. Among them, the par locus of pAD1 is one of the exceptional RNA addiction systems. Pheromone-responsive plasmids contribute also to enterococcal phenotype being an important vehicle of antibiotic resistance in this genus. Both types of acquired vancomycin resistance determinants, vanA and vanB, as well many other resistant phenotypes, were found to be located on these plasmids. They also encode two basic agents of enterococcal virulence, i.e. aggregation substance (AS) and cytolysin. AS participates in mating-pair formation during conjugation but can also facilitate the adherence ofenterococci to human tissues during infection. The second protein, cytolysin, displays hemolytic activity and helps to invade eukaryotic cells. There are still many aspects of the nature of pheromone plasmids that remain unclear and more detailed studies are needed to understand their uniqueness and complexity.
Topics: Conjugation, Genetic; Enterococcus; Gene Expression Regulation, Bacterial; Gram-Positive Bacterial Infections; Humans; Pheromones; Plasmids; Virulence
PubMed: 20734751
DOI: No ID Found -
Scientific Reports Jan 2022Intestinal gluconeogenesis (IGN), gastric bypass (GBP) and gut microbiota positively regulate glucose homeostasis and diet-induced dysmetabolism. GBP modulates gut...
Intestinal gluconeogenesis (IGN), gastric bypass (GBP) and gut microbiota positively regulate glucose homeostasis and diet-induced dysmetabolism. GBP modulates gut microbiota, whether IGN could shape it has not been investigated. We studied gut microbiota and microbiome in wild type and IGN-deficient mice, undergoing GBP or not, and fed on either a normal chow (NC) or a high-fat/high-sucrose (HFHS) diet. We also studied fecal and urine metabolome in NC-fed mice. IGN and GBP had a different effect on the gut microbiota of mice fed with NC and HFHS diet. IGN inactivation increased abundance of Deltaproteobacteria on NC and of Proteobacteria such as Helicobacter on HFHS diet. GBP increased abundance of Firmicutes and Proteobacteria on NC-fed WT mice and of Firmicutes, Bacteroidetes and Proteobacteria on HFHS-fed WT mice. The combined effect of IGN inactivation and GBP increased abundance of Actinobacteria on NC and the abundance of Enterococcaceae and Enterobacteriaceae on HFHS diet. A reduction was observed in the amounf of short-chain fatty acids in fecal (by GBP) and in both fecal and urine (by IGN inactivation) metabolome. IGN and GBP, separately or combined, shape gut microbiota and microbiome on NC- and HFHS-fed mice, and modify fecal and urine metabolome.
Topics: Actinobacteria; Animals; DNA, Bacterial; Enterobacteriaceae; Enterococcaceae; Fatty Acids, Volatile; Firmicutes; Gastric Bypass; Gastrointestinal Microbiome; Gluconeogenesis; Intestines; Male; Metabolome; Mice; Mice, Inbred C57BL; Phylogeny; Proteobacteria; Stomach
PubMed: 35082330
DOI: 10.1038/s41598-022-04902-y -
Indian Journal of Medical Microbiology 2011
Topics: Adult; Aged; Anti-Bacterial Agents; Enterococcus; Gram-Positive Bacterial Infections; Humans; Male; Microbial Sensitivity Tests; Vancomycin; Vancomycin Resistance
PubMed: 21304202
DOI: 10.4103/0255-0857.76531 -
Food Research International (Ottawa,... Oct 2023Fermented fish and fermented fish-based products are part of the diet of many countries all over the world. Their popularity is not only due to the unique flavor, the... (Review)
Review
Fermented fish and fermented fish-based products are part of the diet of many countries all over the world. Their popularity is not only due to the unique flavor, the distinct texture, and the good nutritional quality, but also to the easiness of the production process, that is commonly based on empirical traditional methods. Fish fermentation techniques ususally rely on the combination of some key steps, including salting, addition of spices or additives, and maintenance of anaerobic conditions, thus selecting for the multiplication of some pro-technological microorganisms. The objective of the present review was to provide an overview of the current knowledge of the microbial communities occurring in fermented fish and fish-based products. Specific information was collected from scientific publications published from 2000 to 2022 with the aim of generating a comprehensive database. The production of fermented fish and fish-based foods was mostly localized in West African countries, Northern European countries, and Southeast Asian countries. Based on the available literature, the microbial composition of fermented fish and fish-based products was delineated by using viable counting combined with identification of isolates, and culture-independent techniques. The data obtained from viable counting highlighted the occurrence of microbial groups usually associated with food fermentation, namely lactic acid bacteria, staphylococci, Bacillus spp., and yeasts. The identification of isolates combined with culture-independent methods showed that the fermentative process of fish-based products was generally guided by lactobacilli (Lactiplantibacillus plantarum, Latilactobacillus sakei, and Latilactobacillus curvatus) or Tetragenococcus spp. depending on the salt concentration. Among lactic acid bacteria populations, Lactococcus spp., Pediococcus spp., Leuconostoc spp., Weissella spp., Enterococcus spp., Streptococcus spp., and Vagococcus spp. were frequently identified. Staphylococcus spp. and Bacillus spp. confirmed a great adaptation to fermented fish-based products. Other noteworthy bacterial taxa included Micrococcus spp., Pseudomonas spp., Psychrobacter spp., Halanaerobium spp., and Halomonas spp. Among human pathogenic bacteria, the occurrence of Clostridium spp. and Vibrio spp. was documented. As for yeast populations, the predominance of Candida spp., Debaryomyces spp., and Saccharomyces spp. was evidenced. The present literature review could serve as comprehensive database for the scientific community, and as a reference for the food industry in order to formulate tailored starter or adjunctive cultures for product improvement.
Topics: Animals; Humans; Acclimatization; Africa, Western; Bacillus; Candida; Databases, Factual; Enterococcaceae; Fishes
PubMed: 37689879
DOI: 10.1016/j.foodres.2023.113112 -
Journal of Microbiology and... Mar 2023In this study, a gene encoding glutamyl (aspartyl)-specific aminopeptidase (PepA; E.C. 3.4.11.7) was cloned from CY54. The translated PepA from CY54 showed very low...
In this study, a gene encoding glutamyl (aspartyl)-specific aminopeptidase (PepA; E.C. 3.4.11.7) was cloned from CY54. The translated PepA from CY54 showed very low similarities with PepAs from and genera. The from CY54 was overexpressed in BL21(DE3) using pET26b(+). The recombinant PepA was purified by using an Ni- NTA column. The size of the recombinant PepA was 39.13 kDa as determined by SDS-PAGE, while its optimum pH and temperature were pH 5.0 and 60°C, respectively. In addition, the PepA was completely inactivated by 1 mM EDTA, indicating its metallopeptidase nature. The m and max of the PepA were 0.98 ± 0.006 mM and 0.1 ± 0.002 mM/min, respectively, when Glu-NA was used as the substrate. This is the first report on PepA from species.
Topics: Glutamyl Aminopeptidase; Fermented Foods; Fishes; Enterococcaceae; Recombinant Proteins; Escherichia coli; Animals
PubMed: 36597589
DOI: 10.4014/jmb.2210.10003 -
The Journal of Infectious Diseases Jun 2016
Topics: Anti-Bacterial Agents; Enterococcus faecalis; Enterococcus faecium; Feces; Gram-Positive Bacterial Infections; Humans; Microbial Sensitivity Tests; Vancomycin
PubMed: 26671888
DOI: 10.1093/infdis/jiv598